锅炉毕设文献翻译
自动化专业毕业论文外文文献翻译
目录Part 1 PID type fuzzy controller and parameters adaptive method (1)Part 2 Application of self adaptation fuzzy-PID control for main steam temperature control system in power station (7)Part 3 Neuro-fuzzy generalized predictive control of boiler steam temperature ..................................................................... (13)Part 4 为Part3译文：锅炉蒸汽温度模糊神经网络的广义预测控制21Part 1 PID type fuzzy controller and Parametersadaptive methodWu zhi QIAO, Masaharu MizumotoAbstract: The authors of this paper try to analyze the dynamic behavior of the product-sum crisp type fuzzy controller, revealing that this type of fuzzy controller behaves approximately like a PD controller that may yield steady-state error for the control system. By relating to the conventional PID control theory, we propose a new fuzzy controller structure, namely PID type fuzzy controller which retains the characteristics similar to the conventional PID controller. In order to improve further the performance of the fuzzy controller, we work out a method to tune the parameters of the PID type fuzzy controller on line, producing a parameter adaptive fuzzy controller. Simulation experiments are made to demonstrate the fine performance of these novel fuzzy controller structures.Keywords: Fuzzy controller; PID control; Adaptive control1. IntroductionAmong various inference methods used in the fuzzy controller found in literatures , the most widely used ones in practice are the Mamdani method proposed by Mamdani and his associates who adopted the Min-max compositional rule of inference based on an interpretation of a control rule as a conjunction of the antecedent and consequent, and the product-sum method proposed by Mizumoto who suggested to introduce the product and arithmetic mean aggregation operators to replace the logical AND (minimum) and OR (maximum) calculations in the Min-max compositional rule of inference.In the algorithm of a fuzzy controller, the fuzzy function calculation is also a complicated and time consuming task. Tagagi and Sugeno proposed a crisp type model in which the consequent parts of the fuzzy control rules are crisp functional representation or crisp real numbers in the simplified case instead of fuzzy sets . With this model of crisp real number output, the fuzzy set of the inference consequence willbe a discrete fuzzy set with a finite number of points, this can greatly simplify the fuzzy function algorithm.Both the Min-max method and the product-sum method are often applied with the crisp output model in a mixed manner. Especially the mixed product-sum crisp model has a fine performance and the simplest algorithm that is very easy to be implemented in hardware system and converted into a fuzzy neural network model. In this paper, we will take account of the product-sum crisp type fuzzy controller.2. PID type fuzzy controller structureAs illustrated in previous sections, the PD function approximately behaves like a parameter time-varying PD controller. Since the mathematical models of most industrial process systems are of type, obviously there would exist an steady-state error if they are controlled by this kind of fuzzy controller. This characteristic has been stated in the brief review of the PID controller in the previous section.If we want to eliminate the steady-state error of the control system, we can imagine to substitute the input (the change rate of error or the derivative of error) of the fuzzy controller with the integration of error. This will result the fuzzy controller behaving like a parameter time-varying PI controller, thus the steady-state error is expelled by the integration action. However, a PI type fuzzy controller will have a slow rise time if the P parameters are chosen small, and have a large overshoot if the P or I parameters are chosen large. So there may be the time when one wants to introduce not only the integration control but the derivative control to the fuzzy control system, because the derivative control can reduce the overshoot of the system's response so as to improve the control performance. Of course this can be realized by designing a fuzzy controller with three inputs, error, the change rate of error and the integration of error. However, these methods will be hard to implement in practice because of the difficulty in constructing fuzzy control rules. Usually fuzzy control rules are constructed by summarizing the manual control experience of an operator who has been controlling the industrial process skillfully and successfully. The operator intuitively regulates the executor to control the process by watching theerror and the change rate of the error between the system's output and the set-point value. It is not the practice for the operator to observe the integration of error. Moreover, adding one input variable will greatly increase the number of control rules, the constructing of fuzzy control rules are even more difficult task and it needs more computation efforts. Hence we may want to design a fuzzy controller that possesses the fine characteristics of the PID controller by using only the error and the change rate of error as its inputs.One way is to have an integrator serially connected to the output of the fuzzy controller as shown in Fig. 1. In Fig. 1,1K and 2K are scaling factors for e and ~ respectively, and fl is the integral constant. In the proceeding text, for convenience, we did not consider the scaling factors. Here in Fig. 2, when we look at the neighborhood of NODE point in the e - ~ plane, it follows from (1) that the control input to the plant can be approximated by(1)Hence the fuzzy controller becomes a parameter time-varying PI controller, itsequivalent proportional control and integral control components are BK2D and ilK1 P respectively. We call this fuzzy controller as the PI type fuzzy controller (PI fc). We can hope that in a PI type fuzzy control system, the steady-state error becomes zero.To verify the property of the PI type fuzzy controller, we carry out some simulation experiments. Before presenting the simulation, we give a description of the simulation model. In the fuzzy control system shown in Fig. 3, the plant model is a second-order and type system with the following transfer function:)1)(1()(21++=s T s T K s G (2) Where K = 16, 1T = 1, and 2T = 0.5. In our simulation experiments, we use thediscrete simulation method, the results would be slightly different from that of a continuous system, the sampling time of the system is set to be 0.1 s. For the fuzzy controller, the fuzzy subsets of e and d are defined as shown in Fig. 4. Their coresThe fuzzy control rules are represented as Table 1. Fig. 5 demonstrates the simulation result of step response of the fuzzy control system with a Pl fc. We can see that the steady-state error of the control system becomes zero, but when the integration factor fl is small, the system's response is slow, and when it is too large, there is a high overshoot and serious oscillation. Therefore, we may want to introduce the derivative control law into the fuzzy controller to overcome the overshoot and instability. We propose a controller structure that simply connects the PD type and the PI type fuzzy controller together in parallel. We have the equivalent structure of that by connecting a PI device with the basic fuzzy controller serially as shown in Fig.6. Where ~ is the weight on PD type fuzzy controller and fi is that on PI type fuzzy controller, the larger a/fi means more emphasis on the derivative control and less emphasis on the integration control, and vice versa. It follows from (7) that the output of the fuzzy controller is(3)3. The parameter adaptive methodThus the fuzzy controller behaves like a time-varying PID controller, its equivalent proportional control, integral control and derivative control components are respectively. We call this new controller structure a PID type fuzzy controller (PID fc). Figs. 7 and 8 are the simulation results of the system's step response of such control system. The influence of ~ and fl to the system performance is illustrated. When ~ > 0 and/3 = 0, meaning that the fuzzy controller behaves like PD fc, there exist a steady-state error. When ~ = 0 and fl > 0, meaning that the fuzzy controller behaves like a PI fc, the steady-state error of the system is eliminated but there is a large overshoot and serious oscillation.When ~ > 0 and 13 > 0 the fuzzy controller becomes a PID fc, the overshoot is substantially reduced. It is possible to get a comparatively good performance by carefully choosing the value of αandβ.4. ConclusionsWe have studied the input-output behavior of the product-sum crisp type fuzzy controller, revealing that this type of fuzzy controller behaves approximately like a parameter time-varying PD controller. Therefore, the analysis and designing of a fuzzy control system can take advantage of the conventional PID control theory. According to the coventional PID control theory, we have been able to propose some improvement methods for the crisp type fuzzy controller.It has been illustrated that the PD type fuzzy controller yields a steady-state error for the type system, the PI type fuzzy controller can eliminate the steady-state error. We proposed a controller structure, that combines the features of both PD type and PI type fuzzy controller, obtaining a PID type fuzzy controller which allows the control system to have a fast rise and a small overshoot as well as a short settling time.To improve further the performance of the proposed PID type fuzzy controller, the authors designed a parameter adaptive fuzzy controller. The PID type fuzzy controller can be decomposed into the equivalent proportional control, integral control and the derivative control components. The proposed parameter adaptive fuzzy controller decreases the equivalent integral control component of the fuzzy controller gradually with the system response process time, so as to increase the damping of the system when the system is about to settle down, meanwhile keeps the proportional control component unchanged so as to guarantee quick reaction against the system's error. With the parameter adaptive fuzzy controller, the oscillation of the system is strongly restrained and the settling time is shortened considerably.We have presented the simulation results to demonstrate the fine performance of the proposed PID type fuzzy controller and the parameter adaptive fuzzy controller structure.Part 2 Application of self adaptation fuzzy-PID control for main steam temperature control system inpower stationZHI-BIN LIAbstract: In light of the large delay, strong inertia, and uncertainty characteristics of main steam temperature process, a self adaptation fuzzy-PID serial control system is presented, which not only contains the anti-disturbance performance of serial control, but also combines the good dynamic performance of fuzzy control. The simulation results show that this control system has more quickly response, better precision and stronger anti-disturbance ability．Keywords：Main steam temperature；Self adaptation；Fuzzy control；Serial control1. IntroductionThe boiler superheaters of modem thermal power station run under the condition of high temperature and high pressure, and the superheater’s temperature is highest in the steam channels．so it has important effect to the running of the whole thermal power station．If the temperature is too high, it will be probably burnt out. If the temperature is too low ,the efficiency will be reduced So the main steam temperature mast be strictly controlled near the given value．Fig l shows the boiler main steam temperature system structure.Fig.1 boiler main steam temperature systemIt can be concluded from Fig l that a good main steam temperature controlsystem not only has adequately quickly response to flue disturbance and load fluctuation, but also has strong control ability to desuperheating water disturbance. The general control scheme is serial PID control or double loop control system with derivative. But when the work condition and external disturbance change large, the performance will become instable. This paper presents a self adaptation fuzzy-PID serial control system. which not only contains the anti-disturbance performance of serial control, but also combines the good dynamic character and quickly response of fuzzy control ．1. Design of Control SystemThe general regulation adopts serial PID control system with load feed forward ．which assures that the main steam temperature is near the given value 540℃in most condition ．If parameter of PID control changeless and the work condition and external disturbance change large, the performance will become in stable ．The fuzzy control is fit for controlling non-linear and uncertain process. The general fuzzy controller takes error E and error change ratio EC as input variables ．actually it is a non-linear PD controller, so it has the good dynamic performance ．But the steady error is still in existence. In linear system theory, integral can eliminate the steady error. So if fuzzy control is combined with PI control, not only contains the anti-disturbance performance of serial control, but also has the good dynamic performance and quickly response.In order to improve fuzzy control self adaptation ability, Prof ．Long Sheng-Zhao and Wang Pei-zhuang take the located in bringing forward a new idea which can modify the control regulation online ．This regulation is:]1,0[,)1(∈-+=αααEC E UThis control regulation depends on only one parameter α.Once αis fixed ．the weight of E and EC will be fixed and the self adaptation ability will be very small ．It was improved by Prof. Li Dong-hui and the new regulation is as follow;]1,0[,,,3,)1(2,)1(1,)1(0,)1({321033221100∈±=-+±=-+±=-+=-+=ααααααααααααE EC E E EC E E EC E E EC E UBecause it is very difficult to find a self of optimum parameter, a new method is presented by Prof ．Zhou Xian-Lan, the regulation is as follow:)0(),ex p(12>--=k ke αBut this algorithm still can not eliminate the steady error ．This paper combines this algorithm with PI control ，the performance is improved ．2. Simulation of Control System3.1 Dynamic character of controlled objectPapers should be limited to 6 pages Papers longer than 6 pages will be subject to extra fees based on their length ．Fig .2 main steam temperature control system structureFig 2 shows the main steam temperature control system structure ，)(),(21s W s W δδare main controller and auxiliary controller,)(),(21s W s W o o are characters of the leading and inertia sections,)(),(21s W s W H H are measure unit.3.2 Simulation of the general serial PID control systemThe simulation of the general serial PID control system is operated by MATLAB, the simulation modal is as Fig.3.Setp1 and Setp2 are the given value disturbance and superheating water disturb & rice .PID Controller1 and PID Controller2 are main controller and auxiliary controller ．The parameter value which comes from references is as follow ：667.37,074.0,33.31)(25)(111111122===++===D I p D I p p k k k s k sk k s W k s W δδFig.3. the general PID control system simulation modal3.3 Simulation of self adaptation fuzzy-PID control system SpacingThe simulation modal is as Fig 4.Auxiliary controller is:25)(22==p k s W δ.Main controller is Fuzzy-PI structure, and the PI controller is:074.0,33.31)(11111==+=I p I p k k s k k s W δFuzzy controller is realized by S-function, and the code is as fig.5.Fig.4. the fuzzy PID control system simulation modalFig 5 the S-function code of fuzzy control3.4 Comparison of the simulationGiven the same given value disturbance and the superheating water disturbance，we compare the response of fuzzy-PID control system with PID serial control system. The simulation results are as fig.6-7.From Fig6-7,we can conclude that the self adaptation fuzzy-PID control system has the more quickly response, smaller excess and stronger anti-disturbance．4. Conclusion(1)Because it combines the advantage of PID controller and fuzzy controller, theself adaptation fuzzy-PID control system has better performance than the general PID serial control system.(2)The parameter can self adjust according to the error E value. so this kind of controller can harmonize quickly response with system stability．Part 3 Neuro-fuzzy generalized predictive controlof boiler steam temperatureXiangjie LIU, Jizhen LIU, Ping GUANAbstract: Power plants are nonlinear and uncertain complex systems. Reliable control of superheated steam temperature is necessary to ensure high efficiency and high load-following capability in the operation of modern power plant. A nonlinear generalized predictive controller based on neuro-fuzzy network (NFGPC) is proposed in this paper. The proposed nonlinear controller is applied to control the superheated steam temperature of a 200MW power plant. From the experiments on the plant and the simulation of the plant, much better performance than the traditional controller is obtained.Keywords: Neuro-fuzzy networks; Generalized predictive control; Superheated steam temperature1. IntroductionContinuous process in power plant and power station are complex systems characterized by nonlinearity, uncertainty and load disturbance. The superheater is an important part of the steam generation process in the boiler-turbine system, where steam is superheated before entering the turbine that drives the generator. Controlling superheated steam temperature is not only technically challenging, but also economically important.From Fig.1,the steam generated from the boiler drum passes through the low-temperature superheater before it enters the radiant-type platen superheater. Water is sprayed onto the steam to control the superheated steam temperature in both the low and high temperature superheaters. Proper control of the superheated steam temperature is extremely important to ensure the overall efficiency and safety of the power plant. It is undesirable that the steam temperature is too high, as it can damage the superheater and the high pressure turbine, or too low, as it will lower the efficiency of the power plant. It is also important to reduce the temperaturefluctuations inside the superheater, as it helps to minimize mechanical stress that causes micro-cracks in the unit, in order to prolong the life of the unit and to reduce maintenance costs. As the GPC is derived by minimizing these fluctuations, it is amongst the controllers that are most suitable for achieving this goal.The multivariable multi-step adaptive regulator has been applied to control the superheated steam temperature in a 150 t/h boiler, and generalized predictive control was proposed to control the steam temperature. A nonlinear long-range predictive controller based on neural networks is developed into control the main steam temperature and pressure, and the reheated steam temperature at several operating levels. The control of the main steam pressure and temperature based on a nonlinear model that consists of nonlinear static constants and linear dynamics is presented in that.Fig.1 The boiler and superheater steam generation process Fuzzy logic is capable of incorporating human experiences via the fuzzy rules. Nevertheless, the design of fuzzy logic controllers is somehow time consuming, as the fuzzy rules are often obtained by trials and errors. In contrast, neural networks not only have the ability to approximate non-linear functions with arbitrary accuracy, they can also be trained from experimental data. The neuro-fuzzy networks developed recently have the advantages of model transparency of fuzzy logic and learning capability of neural networks. The NFN is have been used to develop self-tuning control, and is therefore a useful tool for developing nonlinear predictive control. Since NFN is can be considered as a network that consists of several local re-gions, each of which contains a local linear model, nonlinear predictive control based onNFN can be devised with the network incorporating all the local generalized predictive controllers (GPC) designed using the respective local linear models. Following this approach, the nonlinear generalized predictive controllers based on the NFN, or simply, the neuro-fuzzy generalized predictive controllers (NFG-PCs)are derived here. The proposed controller is then applied to control the superheated steam temperature of the 200MW power unit. Experimental data obtained from the plant are used to train the NFN model, and from which local GPC that form part of the NFGPC is then designed. The proposed controller is tested first on the simulation of the process, before applying it to control the power plant.2. Neuro-fuzzy network modellingConsider the following general single-input single-output nonlinear dynamic system:),1(),...,(),(),...,1([)(''+-----=uy n d t u d t u n t y t y f t y ∆+--/)()](),...,1('t e n t e t e e (1)where f[.]is a smooth nonlinear function such that a Taylor series expansion exists, e(t)is a zero mean white noise and Δis the differencing operator,''',,e u y n n n and d are respectively the known orders and time delay of the system. Let the local linear model of the nonlinear system (1) at the operating point )(t o be given by the following Controlled Auto-Regressive Integrated Moving Average (CARIMA) model:)()()()()()(111t e z C t u z B z t y z A d ----+∆= (2) Where )()(),()(1111----∆=z andC z B z A z A are polynomials in 1-z , the backward shift operator. Note that the coefficients of these polynomials are a function of the operating point )(t o .The nonlinear system (1) is partitioned into several operating regions, such that each region can be approximated by a local linear model. Since NFN is a class of associative memory networks with knowledge stored locally, they can be applied to model this class of nonlinear systems. A schematic diagram of the NFN is shown in Fig.2.B-spline functions are used as the membership functions in theNFN for the following reasons. First, B-spline functions can be readily specified by the order of the basis function and the number of inner knots. Second, they are defined on a bounded support, and the output of the basis function is always positive, i.e.,],[,0)(j k j j k x x λλμ-∉=and ],[,0)(j k j j k x x λλμ-∈>.Third, the basis functions form a partition of unity, i.e.,.][,1)(min,∑∈≡j mam j k x x x x μ(3)And fourth, the output of the basis functions can be obtained by a recurrence equation.Fig. 2 neuro-fuzzy network The membership functions of the fuzzy variables derived from the fuzzy rules can be obtained by the tensor product of the univariate basis functions. As an example, consider the NFN shown in Fig.2, which consists of the following fuzzy rules: IF operating condition i (1x is positive small, ... , and n x is negative large),THEN the output is given by the local CARIMA model i:...)()(ˆ...)1(ˆ)(ˆ01+-∆+-++-=d t u b n t y a t y a t yi i a i in i i i a )(...)()(c i in i b i in n t e c t e n d t u b c b -+++--∆+ (4)or )()()()()(ˆ)(111t e z C t u z B z t yz A i i i i d i i ----+∆= (5) Where )()(),(111---z andC z B z A i i i are polynomials in the backward shift operator 1-z , and d is the dead time of the plant,)(t u i is the control, and )(t e i is a zero mean independent random variable with a variance of 2δ. The multivariate basis function )(k i x a is obtained by the tensor products of the univariate basis functions,p i x A a nk k i k i ,...,2,1,)(1==∏=μ (6)where n is the dimension of the input vector x , and p , the total number of weights in the NFN, is given by,∏=+=nk i i k R p 1)( (7)Where i k and i R are the order of the basis function and the number of inner knots respectively. The properties of the univariate B-spline basis functions described previously also apply to the multivariate basis function, which is defined on the hyper-rectangles. The output of the NFN is,∑∑∑=====p i i i p i ip i i i a y aa yy 111ˆˆˆ (8) 3. Neuro-fuzzy modelling and predictive control of superheatedsteam temperatureLet θbe the superheated steam temperature, and θμ, the flow of spray water to the high temperature superheater. The response of θcan be approximated by a second order model:The linear models, however, only a local model for the selected operating point. Since load is the unique antecedent variable, it is used to select the division between the local regions in the NFN. Based on this approach, the load is divided into five regions as shown in Fig.3,using also the experience of the operators, who regard a load of 200MW as high,180MW as medium high,160MW as medium,140MW as medium low and 120MW as low. For a sampling interval of 30s , the estimated linear local models )(1-z A used in the NFN are shown in Table 1.Fig. 3 Membership function for local modelsTable 1 Local CARIMA models in neuro-fuzzy modelCascade control scheme is widely used to control the superheated steam temperature. Feed forward control, with the steam flow and the gas temperature as inputs, can be applied to provide a faster response to large variations in these two variables. In practice, the feed forward paths are activated only when there are significant changes in these variables. The control scheme also prevents the faster dynamics of the plant, i.e., the spray water valve and the water/steam mixing, from affecting the slower dynamics of the plant, i.e., the high temperature superheater. With the global nonlinear NFN model in Table 1, the proposed NFGPC scheme is shown in Fig.4.Fig. 4 NFGPC control of superheated steam temperature with feed-for-ward control.As a further illustration, the power plant is simulated using the NFN model given in Table 1,and is controlled respectively by the NFGPC, the conventional linear GPC controller, and the cascaded PI controller while the load changes from 160MW to 200MW.The conventional linear GPC controller is the local controller designed for the“medium”operating region. The results are shown in Fig.5,showing that, as expected, the best performance is obtained from the NFGPC as it is designed based on a more accurate process model. This is followed by the conventional linear GPC controller. The performance of the conventional cascade PI controller is the worst, indicating that it is unable to control satisfactory the superheated steam temperature under large load changes. This may be the reason for controlling the power plant manually when there are large load changes.Fig.5 comparison of the NFGPC, conventional linear GPC, and cascade PI controller.4. ConclusionsThe modeling and control of a 200 MW power plant using the neuro-fuzzy approach is presented in this paper. The NFN consists of five local CARIMA models.The out-put of the network is the interpolation of the local models using memberships given by the B-spline basis functions. The proposed NFGPC is similarly constructed, which is designed from the CARIMA models in the NFN. The NFGPC is most suitable for processes with smooth nonlinearity, such that its full operating range can be partitioned into several local linear operating regions. The proposed NFGPC therefore provides a useful alternative for controlling this class of nonlinear power plants, which are formerly difficult to be controlled using traditional methods.Part 4 为Part3译文：锅炉蒸汽温度模糊神经网络的广义预测控制Xiangjie LIU, Jizhen LIU, Ping GUAN摘要：发电厂是非线性和不确定性的复杂系统。
济南大学毕业设计外文资料翻译参考格式(理工科类)2014
Powder Technology ,2007,178:114–118)Regulating characteristics of loop seal in a 65 t/h oil shale-fired circulating fluidized bed boilerXiangxin Han, Zhigang Cui, Xiumin Jiang⁎, Jianguo LiuInstitute of Thermal Energy Engineering, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, PR China摘要本文对65t/h油页岩燃烧流化床锅炉的环封调节特性的研究是为了引导一个工业冷却试验。
环封的起始特性、空气供给度的影响和密闭液态空气是需要调查的。
与其他的校正模型比，保持流化空气速率恒定和调节供应空气流量的联合监控模式可使环封获得更好的调节质量，也为循环流化床锅炉稳定运行提供更可靠的保证。
为了防止循环材料在循环底部的沉积和结渣,流化空气流量和空气供应度最好为分别为循环材料的最小流化速度的2-3倍和1.2-1.5倍。
这些实验结果可以为调节65t/h循环流化床锅炉的热条件和设计一个新的环封作为一个参考。
关键词油页岩，循环流化床，环封，调节特性曲线1.引言油页岩的燃烧技术主要包括粉燃料炉、气泡流化床和循环流化床。
因为它非常低的污染排放量和对低级的化石燃料的良好适应性,油页岩循环流化床技术已经被广泛认为是在所有油页岩的利用率模式中最干净、最经济的途径。
作为一个循环流化床锅炉循环回路的重要组成部分,固体循环回收系统控制固体循环率。
一般来说,有两种类型的阀门可用于固体循环系统:一类是是机械阀,另一类是是非机械阀。
典型机械阀门有旋转形，螺丝形,蝶形,和滑动形阀门,机械的移动部件驱动并控制燃料的流动率。
锅炉的计算机控制外文翻译外文文献英文文献
英文翻译Boiler computer controlBoiler computer control：The boiler micro computer control, is a new technology which the recent years developed, it was the microcomputer soft, the hardware, the automatic control, the boiler energy conservation and soon several technical in close integration with product, our country existing center, small boiler more than 300,000, the coal consumption accounted for our country raw coal output every year 1/3, at present the majority industry boiler still was at the energy consumption to be high, to waste, the environmental pollution in a big way and so on the serious production condition. Enhances the thermal efficiency, reduces the coal consumption, carries on the control with the microcomputer is has the profound significance the work. As the boiler control device, its primary mission is guaranteed the boiler the security, is stable, the economical movement, reduces operator's labor intensity. Uses the micro computer control, can carry on the process to the boiler the automatic detection, the automatic control and so on many functions. The boiler microcomputer control system, generally is composed by the below several parts, namely by the boiler main body, a measuring appliance, the microcomputer, the hand automatic cut over operation, the implementing agency and the valve, the slippery difference electrical machinery and so on partially is composed, a measuring appliance the boiler temperature, the pressure, the current capacity, the oxygen quantity, the rotational speed isometric transforms the voltage, the electric current and so on sends in the microcomputer, the hand automatic cut over operation part, manual when by the operator hand control, controls the slippery difference electrical machinery and the valve with themanipulator and so on, is automatic when sends out the control signal to the microcomputer partially to carry on the automatic operation after the execution. The microcomputer carries on the monitor to the entire boiler movement, reports to the police, the control guaranteed the boiler is normal, reliably moves, except for this for guaranteed the boiler movement these curity, when carries on the microcomputer system design, to the boiler water level, the boiler dome pressure and so on the important parameter should establish the conventional measuring appliance and the alarm device, guaranteed the water level and the dome pressure have the dual even tertiary alarm device, this is essential, in order to avoid the boiler has the significant accident.Control system:The boiler is a more complex controlled member, it not only adjustment quantity many, moreover between various types and quantities mutually relates, mutually affects, mutually restricts, boiler interior energy conversion mechanism quite complex, therefore must establish a more ideal mathematical model to the boiler quite to be difficult. Therefore, has made the boiler system simplification processing, decomposes is three relatively independent governing systems. Certainly also may subdivide other system like amount of wind control loops in certain systems, but it mainly is following three parts: (1) the chamber negative pressure (2) the boiler combustion process has three duties for the main tuning quantity special burning regulator system: To coal control, to wind control, chamber negative pressure control. The maintenance coal gas and the air proportion cause the air too much coefficient about 1.08, the combustion process efficiency, the maintenance chamber negative pressure, therefore the boiler combustion process automatic control is a complex question. As for 3×6.5t/h the boiler burning diffuses the blast furnace coal gas, the request is the blast furnace coal gas which maximum limit uses diffuses, therefore may most greatly strive according to the boiler to move, does not make the strict request to the steam pressure; The burning efficiency does not make a higher request. Such boiler combustion process automatic control simplifies as the chamber negativepressure primarily parameter decides the coal gas flow control. (3) the chamber negative pressure Pf size is directed the amount of wind, the drum amount of wind and the coal spirit (pressure)three influences. The chamber negative pressure too is small, the chamber and outside divulges the blast furnace coal gas to the outside to riching, endangers the equipment and the movement personnel's security. The negative pressure too is big, the chamber leaks the amount of wind to increase, discharges fume the loss to increase, drawing fan electricity consumes the increase. Tried to find out according to the many years man-power manual regulation that, 6.5t/hboiler Pf=100Pa carries on the design. The adjustment method is the original state first by the manual regulation air and the coal gas proportion, achieved the ideal burning condition, all opens when the drawing fan achieved chamber negative pressure 100Pa, after the investment is automatic, only adjusts the coal gas reed valve, enable under the fluctuation of pressure the blast furnace coal gas current capacity to tend to the original state coal gas current capacity, maintains in burning the blast furnace coal gas and the air proportion achieves the optimum condition.Boiler water-level control unit ：The steam drum water level is affects the boiler safe operation the important parameter, the water level excessively high, can destroy the soft drink disengaging gear the normal work, is serious when can cause the steam including water to increase, increases on the pipe wall the scaling and the influence steam quality. Water level excessively low, then can destroy the water cycle, causes Water Wall bursting, is serious when can create does the pot, damages the steam drum. Therefore its value has outdone lowly all possibly creates the significant accident. It is adjusted the quantity is the steam drum water level, but adjusts the quantity is for the water current capacity, through to gives the water current capacity the adjustment, enables the steam drum interior the material to achieve the dynamical equilibrium, changes in the permission scope, because the boiler steam drum water level assumes the positive character isticto the vapor current capacity and for the fluent quantity changer But when load (vapor current capacity) sharp growth, the performance actually is "Counter response characteristic "Namely so-called " False water level " Creates this reason is because time load increase, causes the dome pressure to drop, causes the steam drum boiling temperature to drop, the water ebullition suddenly intensifies, forms the massive steam bubbles, but makes the water level to raise. The steam drum water monitor system, in the essence is maintains the boiler turnover water volume balance the system. It is by the water level took the water volume balance or not control target, through adjusts the water volume how many to achieve the turnover balance, maintains the steam drum water level in the soft drink separation contact surface biggest steam drum nearby the position line, enhances the boiler the vaporization efficiency, the guarantee production safety. Because the boiler water level system is equipped with Since the balance the ability to control the object, in the movement has the false water level phenomenon, in the practical application may use the water level single impulse, the water level steam quantity double weight and the water level, the steam quantity according to the situation, gives the water volume three impulses the control systems. Eliminates the oxygen pressure and the water-level control: Partially eliminates the oxygen to use the single impulse control plan, single return route PID adjustment.Monitoring management system management system:Above the control system generally completes the control by PLC or other hardware systems below, but must complete the function in on position computer: Real-time accurately examines the boiler the movement parameter: For comprehensively grasps the overall system the movement operating mode, the supervisory system the real-time monitor and the gathering boiler related craft parameter, the electrical parameter, as well as the equipment running status and so on. The system has the rich graph storehouse, through the configuration may the boiler equipment graph together with the related movement parameter demonstration in the picture; In addition, but also can tabulate the parameter or form and so on grouping demonstrates. The generalized analysis promptly sends out the control command: The supervisory system basis monitors the boiler performance data, according to the control strategy which establishes, sends out the control command, adjusts the boilersystem equipment the movement, thus guaranteed the boiler is highly effective, the reliable movement.(1) diagnoses the breakdown with to report to the police the management: The host controls the center to be allowed to demonstrate, the management, the transmission boiler movement each kind of alarm, thus causes boiler safe explosion-proof, the safe operation rank big enhancement. At the same time, to the records management which reports to the police may cause the owner regarding boiler movement each kind of question, weakness and so on to know from A to Z. In order to guarantee the boiler systematic security, reliably moves, the supervisory system will act according to the parameter which will monitor to carry on the breakdown diagnosis, once will break down, the supervisory system promptly on the operator screen the visual display alarm spot. Reports to the police the correlation demonstration function to cause the user definition the demonstration picture to relate with each spot, like this, when reports to the police occurs, the operator may immediately visit should report to the police the emergency procedures which detailed information and defers to recommends adopts to carry on processing. (2) historic record movement parameter: The supervisory system real-time database will maintain the boiler movement parameter the historic record, moreover supervisory system also. Is equipped with special reports to the police the event diary, with records reports to the police/the event information and operator's change The historic record data basis operator's request, the system may demonstrate is the spurt value, also may for some period of time in mean value. The historic record data may have the many kinds of display mode, for example display mode and so on curve, specific graph, report form; In addition the historic record data also may by apply take the network as the foundation many kinds of application software. (3) calculates the movement parameter: The boiler movement certain movement parameters cannot directly survey ,like the year movement load, the steam consumption, make up the water volume, the condensed water returns to the quantity, the equipment accumulation running time and so on. The supervisory system has provided the rich standard processing algorithm, according to movement parameter which obtains, Derived quantity calculates these.译文:锅炉的计算机控制锅炉的计算机控制：锅炉微计算机控制，是近年来开发的一项新技术，它是微型计算机软、硬件、自动控制、锅炉节能等几项技术紧密结合的产物，我国现有中、小型锅炉30多万台，每年耗煤量占我国原煤产量的1/3，目前大多数工业锅炉仍处于能耗高、浪费大、环境污染等严重的生产状态。
燃煤锅炉 外文翻译 外文文献 英文文献 中英翻译
Controlling the Furnace Process in Coal-Fired BoilersThe unstable trends that exist in the market of fuel supplied to thermal power plants and the situations in which the parameters of their operation need to be changed (or preserved), as well as the tendency toward the economical and environmental requirements placed on them becoming more stringent, are factors that make the problem of controlling the combustion and heat transfer processes in furnace devices very urgent. The solution to this problem has two aspects. The first involves development of a combustion technology and,accordingly, the design of a furnace device when new installations are designed. The second involves modernization of already existing equipment. In both cases,the technical solutions being adopted must be properly substantiated with the use of both experimental and calculation studies.The experience Central Boiler-Turbine Institute Research and Production Association (Ts KTI) and Zi O specialists gained from operation of boilers and experimental investigations they carried out on models allowed them to propose several new designs of multicell and maneuverable—in other words, controllable—furnace devices that had been put in operation at power stations for several years. Along with this, an approximate zero-one-dimensional, zone wise calculation model of the furnace process in boilers had been developed at the Tsk Ti, which allowed Tsk Ti specialists to carry out engineering calculations of the main parameters of this process and calculate studies of furnaces employing different technologies of firing and combustion modes .Naturally, furnace process adjustment methods like changing the air excess factor, stack gas recirculation fraction, and distribution of fuel and air among the tiers of burners, as well as other operations written in the boiler operational chart, are used during boiler operation.However, the effect they have on the process is limited in nature. On the other hand, control of the furnace process in a boiler implies the possibility of making substantial changes in the conditions under which the combustion and heat transfer proceed in order to considerably expand the range ofloads, minimize heat losses, reduce the extent to which the furnace is contaminated with slag, decrease the emissions of harmful substances, and shift to another fuel. Such a control can be obtained by making use of the following three main factors:(i) the flows of oxidizer and gases being set to move in the flame in a desired aerodynamic manner;(ii) the method used to supply fuel into the furnace and the place at which it is admitted thereto;(iii) the fineness to which the fuel is milled.The latter case implies that a flame-bed method is used along with the flame method for combusting fuel.The bed combustion method can be implemented in three design versions: mechanical grates with a dense bed, fluidized-bed furnaces, and spouted-bed furnaces.As will be shown below, the first factor can be made to work by setting up bulky vorticisms transferring large volumes of air and combustion products across and along the furnace device. If fuel is fired in a flame, the optimal method of feeding it to the furnace is to admit it to the zones near the centers of circulating vorticisms, a situation especially typical of highly intense furnace devices. The combustion process in these zones features a low air excess factor (α< 1) and a long local time for which the components dwell in them, factors that help make the combustion process more stable and reduce the emission of nitrogen oxides .Also important for the control of a furnace process when solid fuel is fired is the fineness to which it is milled; if we wish to minimize incomplete combustion, the degree to which fuel is milled should be harmonized with the location at which the fuel is admitted into the furnace and the method for supplying it there, for the occurrence of unburned carbon may be due not only to incomplete combustion of large-size fuel fractions, but also due to fine ones failing to ignite (especially when the content of volatiles Daff < 20%).Owing to the possibility of pictorially demonstrating the motion of flows, furnace aerodynamics is attracting a great deal of attention of researchers and designers who develop and improve furnace devices. At the same time, furnace aerodynamics lies at the heart of mixing (mass transfer), a process the quantitativeparameters of which can be estimated only indirectly or by special measurements. The quality with which components are mixed in the furnace chamber proper depends on the number, layout, and momenta of the jets flowing out from individual burners or nozzles, as well as on their interaction with the flow of flue gases, with one another, or with the wall.It was suggested that the gas-jet throw distance be used as a parameter determining the degree to which fuel is mixed with air in the gas burner channel. Such an approach to estimating how efficient the mixing is may to a certain degree be used in analyzing the furnace as a mixing apparatus. Obviously, the greater the jet length (and its momentum), the longer the time during which the velocity gradient it creates in the furnace will persist there, a parameter that determines how completely the flows are mixed in it. Note that the higher the degree to which a jet is turbulence at the outlet from a nozzle or burner, the shorter the distance which it covers, and, accordingly, the less completely the components are mixed in the furnace volume. Once through burners have advantages over swirl ones in this respect.It is was proposed that the extent to which once through jets are mixed as they penetrate with velocity w2 and density ρ2 into a transverse (drift) flow moving with velocity w1 and having density ρ1 be correlated with the relative jet throw distance in the following wayWhere ks is a proportionality factor that depends on the “pitch” between the jet axes (ks= 1.5–1.8).The results of an experimental investigation in which the mixing of gas with air in a burner and then in a furnace was studied using the incompleteness of mixing as a parameter are reported in 5.A round once through jet is intensively mixed with the surrounding medium in a furnace within its initial section, where the flow velocity at the jet axis is still equal to the velocity w2 at the nozzle orifice of radius r0.The velocity of the jet blown into the furnace drops very rapidly beyond the confines of the initial section, and the axis it has in the case of wall-mounted burners bends toward the outlet from the furnace.One may consider that there are three theoretical models for analyzing the mixing of jets with flow rate G2 that enter into a stream with flow rate G1. The firstmodel is for the case when jets flow into a “free” space (G1= 0),the second model is for the case when jets flow into a transverse (drift) current with flow rate G1 G2，and the third model is for the case when jets flow into a drift stream with flow rateG1<G2. The second model represents mixing in the channel of a gas burner, and the third model represents mixing in a furnace chamber. We assume that the mixing pattern we have in a furnace is closer to the first model than it is to the second one, since 0 <G1/G2< 1, and we will assume that the throw distance h of the jet being drifted is equal to the length S0 of the “free” jet’s initial section. The ejection ability of the jet being drifted then remains the same as that of the “free” jet, and the length of the initial section can be determined using the well-known empirical formula of G.N. Amphibrachic [6] ：S0= 0.67r0/a, (2)where a is the jet structure factor and r0 is the nozzle radius.At a = 0.07, the length of the round jet’s initial section is equal to 10 r0 and the radius the jet has at the transition section (at the end of the initial section) is equal to 3.3 r0. The mass flow rate in the jet is doubled in this case. The corresponding minimum furnace cross-sectional area Ff for a round once through burner with the outlet cross-sectional area Fb will then be equal to and t he ratio Ff/Fb≈20. This value is close to the actual values found in furnaces equipped with once through burners. In furnaces equipped with swirl burners, a= 0.14 and Ff/Fb≈10. In both cases, the interval between the burners is equal to the jet diameter in the transition section d tr , which differs little from the value that has been established in practice and recommended in [7].The method traditionally used to control the furnace process in large boilers consists of equipping them with a large number of burners arranged in several tiers. Obviously, if the distance between the tiers is relatively small, operations on disconnecting or connecting them affect the entire process only slightly. A furnace design employing large flat-flame burners equipped with means for controlling the flame core position using the aerodynamic principle is a step forward. Additional possibilities for controlling the process in TPE-214 and TPE-215 boilers with a steam output of 670 t/h were obtained through the use of flat-flame burners arranged in two tiers with a large distance between the tiers; this made it possible not only to raise orlower the flame, but also to concentrate or disperse the release of heat in it [1]. A very tangible effect was obtained from installing multicell (operating on coal andopen-hearth, coke, and natural gases) flat-flame burners in the boilers of cogeneration stations at metallurgical plants in Ukraine and Russia.Unfortunately, we have to state that, even at present, those in charge of selecting the type, quantity, and layout of burners in a furnace sometimes adopt technical solutions that are far from being optimal. This problem should therefore be considered in more detail.If we increase the number of burners nb in a furnace while retaining their total cross-sectional area (ΣFb=idem) and the total flow rate of air through them, their equivalent diameters deq will become smaller, as will the jet momentums GB, resulting in a corresponding decrease in the jet throw distance Hb and the mass they eject. The space with high velocity gradients also becomes smaller, resulting in poorer mixing in the furnace as a whole. This factor becomes especially important when the emissions of Box and CO are suppressed right inside the furnace using staged combustio n (at αb < 1) under the conditions of a Fortinbras nonuniform distribution of fuel among the burners.In [1], a quantitative relationship was established between the parameters characterizing the quality with which once through jets mix with one another as they flow into a limited space with the geometrical parameter of concentration = with nb = idem and GB = idem. By decreasing this parameter we improve the mass transfer in the furnace; however, this entails an increase in the flow velocity and the expenditure of energy (pressure drop) in the burners with the same Fb. At the same time, we know from experience and calculations that good mixing in a furnace can be obtained without increasing the head loss if we resort to large long-range jets. This allows a much less stringent requirement to be placed on the degree of uniformity with which fuel must be distributed among the burners. Moreover, fuel may in this case be fed to the furnace location where it is required from process control considerations.For illustration purposes, we will estimate the effect the number of burners has on the mixing in a furnace at = = idem. schematically shows the plan views of two furnace chambers differing in the number of once through round nozzles (two andfour) placed in a tier (on one side of the furnace). The furnaces have the same total outlet cross-sectional areas of the nozzles (ΣF b) and the same jet velocities related to these areas (wb). The well-known swirl furnace of the TsKTI has a design close to the furnace arrangement under consideration. According to the data of [1], the air fraction βair that characterizes the mixing and enters through once through burners into the furnace volume beneath them can be estimated using the formula βair = 1 – (3) which has been verified in the range = 0.03–0.06 for a furnace chamber equipped with two frontal once through burners. Obviously, if we increase the number of burners by a factor of 2, their equivalent diameter, the length of the initial section of jets S0 and the area they “serve” will reduce by a factor of Then, for example, at = 0.05, the fraction βair will decrease from 0.75 to 0.65. Thus, Eq. (3) may be written in the following form for approximately assessing the effect of once through burners on the quality of mixing in a furnace:βair = 1 – 3.5f nb ' ,where is the number of burners (or air nozzles) on one wall when they are arranged in one tier both in onesided and opposite manners.The number of burners may be tentatively related to the furnace depth af (at the same = idem) using the expression (5)It should be noted that the axes of two large opposite air nozzles ( = 1)—an arrangement implemented in an inverted furnace—had to be inclined downward by more than 50° [8].One well-known example of a furnace device in which once through jets are used to create a large vortex covering a considerable part of its volume is a furnace with tangentially arranged burners. Such furnaces have received especially wide usein combination with pulverizing fans. However, burners with channels having a small equivalent diameter are frequently used for firing low-calorific brown coals with high content of moisture. As a result, the jets of air-dust mixture and secondary air that go out from their channels at different velocities(w2/w1 = 2–3) become turbulence and lose the ability to be thrown a long distance; as a consequence, the flame comes closer to the water walls and the latter are contaminated with slag. One method by which the tangential combustion scheme can be improved consists of organizing the so-called concentric admission of large jets of air-dust mixture and secondary air with the fueland air nozzles spaced apart from one another over the furnace perimeter, accompanied by intensifying the ventilation of mills [9, 10]. Despite the fact that the temperature level in the flame decreases, the combustion does not become less stable because the fuel mixes with air in a stepwise manner in a horizontal plane.V ortex furnace designs with large cortices the rotation axes of which are arranged transversely with respect to the main direction of gas flow have wide possibilities in terms of controlling the furnace process. In [1], four furnace schemes with a controllable flame are described, which employ the principle of large jets colliding with one another; three of these schemes have been implemented. A boiler with a steam capacity of 230 t/h has been retrofitted in accordance with one of these schemes (with an inverted furnace) . Tests of this boiler, during which air-dust mixture was fed at a velocity of 25–30 m/s from the boiler front using a high concentration dust system, showed that the temperature of gases at the outlet from the furnace had a fairly uniform distribution both along the furnace width and depth . A simple method of shifting the flame core over the furnace height was checked during the operation of this boiler, which consisted of changing the ratio of air flow rates through the front and rear nozzles;this allowed a shift to be made from running the furnace in adry-bottom mode to a slag-tap mode and vice Versace. A bottom-blast furnace scheme has received rather wide use in boilers equipped with different types of burners and mills. Boilers with steam capacities ranging from 50 to 1650 t/h with such an aerodynamic scheme of furnaces manufactured by ZiO and Bergomask have been installed at a few power stations in Russia and abroad . We have to point out that, so far as the efficiency of furnace process control is concerned, a combination of the following two aerodynamic schemes is of special interest: the inverted scheme and the bottom-blast one. The flow pattern and a calculation analysis of the furnace process in such a furnace during the combustion of lean coal are presented in [13].Below, two other techniques for controlling the furnace process are considered. Boilers with flame–stoker furnaces have gained acceptance in industrial power engineering, devices that can be regarded to certain degree as controllable ones owing to the presence of two zones in them . Very different kinds of fuel can be jointly combusted in these furnaces rather easily. An example of calculating such a furnacedevice is given in [2]. As for boilers of larger capacity, work on developing controllable two-zone furnaces is progressing slowly . The development of a furnace device using the so-called VIR technology (the transliterated abbreviation of the Russian introduction, innovation, and retrofitting) can be considered as holding promise in this respect. Those involved in bringing this technology to the state of industry standard encountered difficulties of an operational nature (the control of the process also presented certain difficulties). In our opinion, these difficulties are due to the fact that the distribution of fuel over fractions can be optimized to a limited extent and that the flow in the main furnace volume has a rather sluggish aerodynamic structure. It should also be noted that the device for firing the coarsest fractions of solid fuel in a spouting bed under the cold funnel is far from being technically perfect.Centrifugal dust concentrators have received acceptance for firing high-reactive coals in schemes employing pulverizing fans to optimize the distribution of fuel as to its flow rate and fractions. The design of one such device is schematically shown in [9]. Figure shows a distribution of fuel flow rates among four tiers of burners that is close to the optimum one. This distribution can be controlled if we furnish dust concentrators with a device with variable blades, a solution that has an adequate effect on the furnace process.燃煤锅炉的燃烧进程控制存在于火电厂的市场的燃料供应，某些操作参数需要改变（或保留）的情况下，以及经济和环境方面倾向的要求使他们变得更加严格的不稳定趋势是导致使控制燃烧与传热过程炉设备非常紧迫的主要因素。
燃煤锅炉的燃烧进程控制大学毕业论文外文文献翻译及原文
毕业设计（论文）外文文献翻译文献、资料中文题目：燃煤锅炉的燃烧进程控制文献、资料英文题目：Controlling the Furnace Process in Coal-Fired Boilers文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期： 2017.02.14Controlling the Furnace Process in Coal-Fired BoilersThe unstable trends that exist in the market of fuel supplied to thermal power plants and the situations in which the parameters of their operation need to be changed (or preserved), as well as the tendency toward the economical and environmental requirements placed on them becoming more stringent, are factors that make the problem of controlling the combustion and heat transfer processes in furnace devices very urgent. The solution to this problem has two aspects. The first involves development of a combustion technology and,accordingly, the design of a furnace device when new installations are designed. The second involves modernization of already existing equipment. In both cases,the technical solutions being adopted must be properly substantiated with the use of both experimental and calculation studies.The experience Central Boiler-Turbine Institute Research and Production Association (Ts KTI) and Zi O specialists gained from operation of boilers and experimental investigations they carried out on models allowed them to propose several new designs of multicell and maneuverable—in other words, controllable—furnace devices that had been put in operation at power stations for several years. Along with this, an approximate zero-one-dimensional, zone wise calculation model of the furnace process in boilers had been developed at the Tsk Ti, which allowed Tsk Ti specialists to carry out engineering calculations of the main parameters of this process and calculate studies of furnaces employing different technologies of firing and combustion modes .Naturally, furnace process adjustment methods like changing the air excess factor, stack gas recirculation fraction, and distribution of fuel and air among the tiers of burners, as well as other operations written in the boiler operational chart, are used during boiler operation.However, the effect they have on the process is limited in nature. On the other hand, control of the furnace process in a boiler implies the possibility of making substantial changes in the conditions under which the combustion and heat transfer proceed in order to considerably expand the range of loads, minimize heat losses, reduce the extent to which the furnace is contaminatedwith slag, decrease the emissions of harmful substances, and shift to another fuel. Such a control can be obtained by making use of the following three main factors:(i) the flows of oxidizer and gases being set to move in the flame in a desired aerodynamic manner;(ii) the method used to supply fuel into the furnace and the place at which it is admitted thereto;(iii) the fineness to which the fuel is milled.The latter case implies that a flame-bed method is used along with the flame method for combusting fuel.The bed combustion method can be implemented in three design versions: mechanical grates with a dense bed, fluidized-bed furnaces, and spouted-bed furnaces.As will be shown below, the first factor can be made to work by setting up bulky vorticisms transferring large volumes of air and combustion products across and along the furnace device. If fuel is fired in a flame, the optimal method of feeding it to the furnace is to admit it to the zones near the centers of circulating vorticisms, a situation especially typical of highly intense furnace devices. The combustion process in these zones features a low air excess factor (α< 1) and a long local time for which the components dwell in them, factors that help make the combustion process more stable and reduce the emission of nitrogen oxides .Also important for the control of a furnace process when solid fuel is fired is the fineness to which it is milled; if we wish to minimize incomplete combustion, the degree to which fuel is milled should be harmonized with the location at which the fuel is admitted into the furnace and the method for supplying it there, for the occurrence of unburned carbon may be due not only to incomplete combustion of large-size fuel fractions, but also due to fine ones failing to ignite (especially when the content of volatiles Daff < 20%).Owing to the possibility of pictorially demonstrating the motion of flows, furnace aerodynamics is attracting a great deal of attention of researchers and designers who develop and improve furnace devices. At the same time, furnace aerodynamics lies at the heart of mixing (mass transfer), a process the quantitative parameters of which can be estimated only indirectly or by special measurements. Thequality with which components are mixed in the furnace chamber proper depends on the number, layout, and momenta of the jets flowing out from individual burners or nozzles, as well as on their interaction with the flow of flue gases, with one another, or with the wall.It was suggested that the gas-jet throw distance be used as a parameter determining the degree to which fuel is mixed with air in the gas burner channel. Such an approach to estimating how efficient the mixing is may to a certain degree be used in analyzing the furnace as a mixing apparatus. Obviously, the greater the jet length (and its momentum), the longer the time during which the velocity gradient it creates in the furnace will persist there, a parameter that determines how completely the flows are mixed in it. Note that the higher the degree to which a jet is turbulence at the outlet from a nozzle or burner, the shorter the distance which it covers, and, accordingly, the less completely the components are mixed in the furnace volume. Once through burners have advantages over swirl ones in this respect.It is was proposed that the extent to which once through jets are mixed as they penetrate with velocity w2 and density ρ2 into a transverse (drift) flow moving with velocity w1 and having density ρ1 be correlated with the relative jet throw distance in the following wayWhere ks is a proportionality factor that depends on the ―pitch‖ between the jet axes (ks= 1.5–1.8).The results of an experimental investigation in which the mixing of gas with air in a burner and then in a furnace was studied using the incompleteness of mixing as a parameter are reported in 5.A round once through jet is intensively mixed with the surrounding medium in a furnace within its initial section, where the flow velocity at the jet axis is still equal to the velocity w2 at the nozzle orifice of radius r0.The velocity of the jet blown into the furnace drops very rapidly beyond the confines of the initial section, and the axis it has in the case of wall-mounted burners bends toward the outlet from the furnace.One may consider that there are three theoretical models for analyzing the mixing of jets with flow rate G2 that enter into a stream with flow rate G1. The first model is for the case when jets flow into a ―free‖ space (G1= 0),the second model isfor the case when jets flow into a transverse (drift) current with flow rate G1 G2，and the third model is for the case when jets flow into a drift stream with flow rateG1<G2. The second model represents mixing in the channel of a gas burner, and the third model represents mixing in a furnace chamber. We assume that the mixing pattern we have in a furnace is closer to the first model than it is to the second one, since 0 <G1/G2< 1, and we will assume that the throw distance h of the jet being drifted is equal to the length S0 of the ―free‖ jet’s initial section. The ejection ability of the jet being drifted then remains the same as that of the ―free‖ jet, and the length of the initial section can be determined using the well-known empirical formula of G.N. Amphibrachic [6] ：S0= 0.67r0/a, (2)where a is the jet structure factor and r0 is the nozzle radius.At a = 0.07, the length of the round jet’s initial section is equal to 10 r0 and the radius the jet has at the transition section (at the end of the initial section) is equal to 3.3 r0. The mass flow rate in the jet is doubled in this case. The corresponding minimum furnace cross-sectional area Ff for a round once through burner with the outlet cross-sectional area Fb will then be equal to and the ratio Ff/Fb≈20. This value is close to the actual values found in furnaces equipped with once through burners. In furnaces equipped with swirl burners, a= 0.14 and Ff/Fb≈10. In both cases, the interval between the burners is equal to the jet diameter in the transition section d tr , which differs little from the value that has been established in practice and recommended in [7].The method traditionally used to control the furnace process in large boilers consists of equipping them with a large number of burners arranged in several tiers. Obviously, if the distance between the tiers is relatively small, operations on disconnecting or connecting them affect the entire process only slightly. A furnace design employing large flat-flame burners equipped with means for controlling the flame core position using the aerodynamic principle is a step forward. Additional possibilities for controlling the process in TPE-214 and TPE-215 boilers with a steam output of 670 t/h were obtained through the use of flat-flame burners arranged in two tiers with a large distance between the tiers; this made it possible not only to raise or lower the flame, but also to concentrate or disperse the release of heat in it [1]. A verytangible effect was obtained from installing multicell (operating on coal andopen-hearth, coke, and natural gases) flat-flame burners in the boilers of cogeneration stations at metallurgical plants in Ukraine and Russia.Unfortunately, we have to state that, even at present, those in charge of selecting the type, quantity, and layout of burners in a furnace sometimes adopt technical solutions that are far from being optimal. This problem should therefore be considered in more detail.If we increase the number of burners nb in a furnace while retaining their total cross-sectional area (ΣFb=idem) and the total flow rate of air through them, their equivalent diameters deq will become smaller, as will the jet momentums GB, resulting in a corresponding decrease in the jet throw distance Hb and the mass they eject. The space with high velocity gradients also becomes smaller, resulting in poorer mixing in the furnace as a whole. This factor becomes especially important when the emissions of Box and CO are suppressed right inside the furnace using staged combustion (at αb < 1) under the conditions of a Fortinbras nonuniform distribution of fuel among the burners.In [1], a quantitative relationship was established between the parameters characterizing the quality with which once through jets mix with one another as they flow into a limited space with the geometrical parameter of concentration = with nb = idem and GB = idem. By decreasing this parameter we improve the mass transfer in the furnace; however, this entails an increase in the flow velocity and the expenditure of energy (pressure drop) in the burners with the same Fb. At the same time, we know from experience and calculations that good mixing in a furnace can be obtained without increasing the head loss if we resort to large long-range jets. This allows a much less stringent requirement to be placed on the degree of uniformity with which fuel must be distributed among the burners. Moreover, fuel may in this case be fed to the furnace location where it is required from process control considerations.For illustration purposes, we will estimate the effect the number of burners has on the mixing in a furnace at = = idem. schematically shows the plan views of two furnace chambers differing in the number of once through round nozzles (two and four) placed in a tier (on one side of the furnace). The furnaces have the same totaloutlet cross-sectional areas of the nozzles (ΣF b) and the same jet velocities related to these areas (wb). The well-known swirl furnace of the TsKTI has a design close to the furnace arrangement under consideration. According to the data of [1], the air fraction βair that characterizes the mixing and enters through once through burners into the furnace volume beneath them can be estimated using the formula βair = 1 – (3) which has been verified in the range = 0.03–0.06 for a furnace chamber equipped with two frontal once through burners. Obviously, if we increase the number of burners by a factor of 2, their equivalent diameter, the length of the initial section of jets S0 and the area they ―serve‖ will reduce by a factor of Then, for example, at = 0.05, the fraction βair will decrease from 0.75 to 0.65. Thus, Eq. (3) may be written in the following form for approximately assessing the effect of once through burners on the quality of mixing in a f urnace:βair = 1 – 3.5f nb ' ,where is the number of burners (or air nozzles) on one wall when they are arranged in one tier both in onesided and opposite manners.The number of burners may be tentatively related to the furnace depth af (at the same = idem) using the expression (5)It should be noted that the axes of two large opposite air nozzles ( = 1)—an arrangement implemented in an inverted furnace—had to be inclined downward by more than 50° [8].One well-known example of a furnace device in which once through jets are used to create a large vortex covering a considerable part of its volume is a furnace with tangentially arranged burners. Such furnaces have received especially wide usein combination with pulverizing fans. However, burners with channels having a small equivalent diameter are frequently used for firing low-calorific brown coals with high content of moisture. As a result, the jets of air-dust mixture and secondary air that go out from their channels at different velocities(w2/w1 = 2–3) become turbulence and lose the ability to be thrown a long distance; as a consequence, the flame comes closer to the water walls and the latter are contaminated with slag. One method by which the tangential combustion scheme can be improved consists of organizing the so-called concentric admission of large jets of air-dust mixture and secondary air with the fuel and air nozzles spaced apart from one another over the furnace perimeter,accompanied by intensifying the ventilation of mills [9, 10]. Despite the fact that the temperature level in the flame decreases, the combustion does not become less stable because the fuel mixes with air in a stepwise manner in a horizontal plane.V ortex furnace designs with large cortices the rotation axes of which are arranged transversely with respect to the main direction of gas flow have wide possibilities in terms of controlling the furnace process. In [1], four furnace schemes with a controllable flame are described, which employ the principle of large jets colliding with one another; three of these schemes have been implemented. A boiler with a steam capacity of 230 t/h has been retrofitted in accordance with one of these schemes (with an inverted furnace) . Tests of this boiler, during which air-dust mixture was fed at a velocity of 25–30 m/s from the boiler front using a high concentration dust system, showed that the temperature of gases at the outlet from the furnace had a fairly uniform distribution both along the furnace width and depth . A simple method of shifting the flame core over the furnace height was checked during the operation of this boiler, which consisted of changing the ratio of air flow rates through the front and rear nozzles;this allowed a shift to be made from running the furnace in adry-bottom mode to a slag-tap mode and vice Versace. A bottom-blast furnace scheme has received rather wide use in boilers equipped with different types of burners and mills. Boilers with steam capacities ranging from 50 to 1650 t/h with such an aerodynamic scheme of furnaces manufactured by ZiO and Bergomask have been installed at a few power stations in Russia and abroad . We have to point out that, so far as the efficiency of furnace process control is concerned, a combination of the following two aerodynamic schemes is of special interest: the inverted scheme and the bottom-blast one. The flow pattern and a calculation analysis of the furnace process in such a furnace during the combustion of lean coal are presented in [13].Below, two other techniques for controlling the furnace process are considered. Boilers with flame–stoker furnaces have gained acceptance in industrial power engineering, devices that can be regarded to certain degree as controllable ones owing to the presence of two zones in them . Very different kinds of fuel can be jointly combusted in these furnaces rather easily. An example of calculating such a furnace device is given in [2]. As for boilers of larger capacity, work on developingcontrollable two-zone furnaces is progressing slowly . The development of a furnace device using the so-called VIR technology (the transliterated abbreviation of the Russian introduction, innovation, and retrofitting) can be considered as holding promise in this respect. Those involved in bringing this technology to the state of industry standard encountered difficulties of an operational nature (the control of the process also presented certain difficulties). In our opinion, these difficulties are due to the fact that the distribution of fuel over fractions can be optimized to a limited extent and that the flow in the main furnace volume has a rather sluggish aerodynamic structure. It should also be noted that the device for firing the coarsest fractions of solid fuel in a spouting bed under the cold funnel is far from being technically perfect.Centrifugal dust concentrators have received acceptance for firing high-reactive coals in schemes employing pulverizing fans to optimize the distribution of fuel as to its flow rate and fractions. The design of one such device is schematically shown in [9]. Figure shows a distribution of fuel flow rates among four tiers of burners that is close to the optimum one. This distribution can be controlled if we furnish dust concentrators with a device with variable blades, a solution that has an adequate effect on the furnace process.。
锅炉系统毕业设计论文中英文资料对照外文翻译文献
中英文资料对照外文翻译文献锅炉系统1 冷凝器1.1 简介欧堡生产的冷凝器是用直管和一个外部密封浮头组成的管壳式冷凝器。
这种冷凝器主要用作废气锅炉，蒸汽加热或洗舱海水加热器的转储冷凝器/冷却器排水。
并取得权威船级社批准。
温度计，排水阀，空气阀，压力表的安装设计为½“BSP内螺纹安装。
这些组件可能是指定的。
而蒸汽或水的控制设备是可选的。
1.2 安装空间要求安装时必须有足够的空间供作清洗，检查或更换管的插入与撤出。
冷凝器必须安置在水平并稳定的表面。
1.3 存储如果冷凝器在安装前要闲置一段时间，应存放在干燥的储藏室里。
如果储藏室潮湿，冷凝器必须放在装有硅胶的包装袋子里。
为了避免破坏，建议冷凝器放在原包装中。
冷凝器已经在交付前做过液压试验。
试验中所用测试媒质含有一定的数额抗腐蚀保护物质。
当冷凝器需闲置的时间较长，建议使用指定产品作为防腐蚀物质1.4 安装冷凝器设计为垂直或水平安装。
在水平安装的情况下，蒸汽喷嘴必须朝上，而冷凝水出口喷嘴朝下。
如果是垂直安装冷凝器，蒸汽入口和海水出口端必须朝上。
排水和空气排放阀必须安装在冷凝器在最低和最高点的中间线的位置。
任何选择性的控制设备必须根据具体指示安装。
步骤A：将冷凝器安装在水平平面上。
步骤B：钻基础固定螺栓孔。
步骤C：将螺栓放入孔中并拧紧。
连接冷凝器步骤D：移除所有的塞子和盲板，然后再连接冷凝器。
步骤E：在连接中确保没有杂质进入。
步骤F：管道连接起来，确保从管道和冷凝器之间没有强制力的产生。
1.5 调试启动前要确保所有连接都牢固地拧紧是很重要的。
同样重要的是，冷凝器和连接管道空气要彻底排出。
步骤A：如果装有安全阀，必须加以调整到最大设计压力或较低。
步骤B：法兰螺栓要拧紧。
拧紧法兰螺栓时始终使用扭矩扳手。
步骤C：运行一小时，停止冷凝器，并重新拧紧所有螺栓。
步骤D：启动阶段，冷凝器的两边都要排出空气，必须认真仔细的检查回路的泄漏。
1.6 性能冷凝器性能须附和传热计算表规定的要求。
锅炉毕设文献翻译
自然循环热水锅炉水动力回路分析法摘要：水动力计算都依据《热水锅炉水动力计算方法》,不足的是这种方法不能准确确定每根单管的工质流量，且不能准确确定工作点。
为了避免其不确定性，研究得出了一种数值水动力计算方法即水动力回路分析法，简称回路分析法。
该方法考虑了各种因素对锅炉本体每根管内工质流量的影响，在其热负荷、结构参数和工质流动阻力系数给定的条件下，可以准确计算出每根单管内的工质流量。
在相同的参数条件下，分别用标准法和回路分析法对某单一循环回路的水动力特性进行计算，计算结果验证了水动力回路分析法的正确性。
然后分别用标准法和回路分析法对一台自然循环热水锅炉的水动力特性进行计算，结果表明水动力回路分析法更准确并可接受。
关键词：热水锅炉；水动力；回路分析法引言：由于自然循环热水锅炉的大容量和对于断电保护、给水质量以及运行水平的低要求，它已经在中国广泛应用[1]。
然而，在上升管和下降管中工质的密度差过小可能会导致自然循环有效压力较低，如果结构不合理，将会产生爆管。
因此，在自然循环热水锅炉设计中，如何确定流动工质的安全速度和避免爆管导致受热面过冷沸腾是非常重要的。
在中国早期，有很多研究者致力于关于自然循环热水锅炉水动力计算的研究，一些人提出了对于几个简单循环回路和某些复杂循环回路的水动力计算方法，但是大多数方法只适用于简单回路。
西安交通大学的朱教授提出了一种应用计算机流体力学分析的方法，他将流动工质的特点和使用一种两端参考作为主动解决方法的直流循环原则做了比较。
这种方法的优势在于解决过程的方便性，但是对于复杂循环的解决过程非常复杂[2]。
自从上世纪七十年代，对于管流分布热力学模型的研究显著增多[3-8]。
目前，水动力计算方法使用“热水锅炉水动力计算法”[9](以下简称一般方法)，它提供了保证循环安全的一般方法。
该方法采用图解的方式确定介质的工作点，这是非常准确和高效的。
在解决整个问题时用到一些假设。
本文的目的是提供一种新的水动力数值计算方法，简称水动力回路分析法，即回路分析法。
工业锅炉节能毕业论文中英文资料外文翻译文献
工业锅炉节能中英文资料外文翻译文献专业英文资料Boiler energy savingIndustrial boiler energy saving technology related to many, what is the most important increase industrial furnace thermal utilization ratio of pot namely, increasing the thermal efficiency of the industrial boiler. This section from burning, transportation line maintenance, new technology and new equipment and the application of the industrial boiler auxiliary equipment of energy saving, pot boiler water processing, etc and the industrial boiler room way of energy saving is discussed in this paper.1. The furnace of industrial boiler furnace arch arch is very important. The role is to make arch furnace chamber of the mixture of gases and radiation and hot gas organization flow, to make the fuel and ignition and combustion when. Sua and at present industrial boiler with the actual YongQiLiang rated load are often not with horse, the use of coal changes greatly, and often have large design coal poor vision, so in actual use, often to furnace necessary improvement in arch coal need to be comfortable.For transformation of the former furnace arch situation, the existing problem is: for the use of coal and coal than design poor miscellaneous, boiler flue gas temperature appear the chamber exports low (about 700℃), more than 200 ℃ design low. The new coal fire late, often appear fire bed broken fire, fire from about 0.6 ~ coal disc 1 cm, furnace combustion is not strong, ash high carbon content. According to the problems furnace arch structure, from improving the ignition of fuel conditions and raise the temperature of boiler furnace to reform.After improvement furnace arch, in actual shipped in from the observed, the transformation effect is good, people away from coal furnace fuel after disc 0.3 MRP on fire, fire bed combustion intense, flame full of degree good, strong rotation. Due to the lower arch before, after extended arch, the arch of the throat and mouth shape between into space from the original 2 cm or so down to 1 cm. To strengthen the disturbance of the air mixed, to form the airflow, strengthen the furnace combustion, improve the efficiency of the district and the whole arch before furnace temperature, make its reach to 1400℃ above, improved the ignition of fuel conditions. Coal in the ignition, of furnace temperature rise, make the carbon content and ash significantly less. The flue gas mixture and strengthen the hydrocyclone separation of flue gas carbon particles needed to fall in the fire bed and new fuel layer further burns out.2. The reasonable air supply and regulationIn the chain furnace, the furnace, the furnace of reciprocating vibration, according to the different characteristics of the combustion process, reasonable air supply, to promote the furnace combustion is very important. As in the chain furnace, along with fuel keep movement, which in turn happen on fire, burning, and burn the stage. Burning along the length direction is the stoker stages, zoning, so along the length direction along the air quantity is also different. The preheating zone along the head and tail burn stage, air requirements small; The burning along the middle stage, air requirements. According to this13characteristic, must use block supply air, to meet the needs of the burning. The current domestic production of the boiler although all are to consider this one characteristic, with the wind in subsection room, and equipped with air inlet adjustment. But according to the survey.3.The secondary airSecond wind to strengthen the air combustion is very effective. Second wind have the following function:(1) strengthen the furnace of air disturbance and mixed, make the furnace of oxygen and flammable gas mixture evenly, make chemical don't fully burning loss and the chamber excess air coefficient reducing. (2) secondary air in furnace flue gas vortex formed, on the one hand, extended the suspension fine coal grain in the chamber of a stroke, increase the fine particles suspended furnace in the residence time of, make it have a full time to burn, make not complete combustion heat loss; Another result of air separation of spiral effect, make coal dust grain and the grain re-blows rejection within, and reduce the small fly ash escape from the quantity, the mechanical incomplete combustion heat loss.英译汉14锅炉的节能工业锅炉的节能技术涉及多方面 , 最主要是提高工业锅炉的热能利用率 , 即提高工业锅炉的热效率。
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自然循环热水锅炉水动力回路分析法
摘要：水动力计算都依据《热水锅炉水动力计算方法》,不足的是这种方法不能准确确定每根单管的工质流量，且不能准确确定工作点。
为了避免其不确定性，研究得出了一种数值水动力计算方法即水动力回路分析法，简称回路分析法。
该方法考虑了各种因素对锅炉本体每根管内工质流量的影响，在其热负荷、结构参数和工质流动阻力系数给定的条件下，可以准确计算出每根单管内的工质流量。
在相同的参数条件下，分别用标准法和回路分析法对某单一循环回路的水动力特性进行计算，计算结果验证了水动力回路分析法的正确性。
然后分别用标准法和回路分析法对一台自然循环热水锅炉的水动力特性进行计算，结果表明水动力回路分析法更准确并可接受。
关键词：热水锅炉；水动力；回路分析法
引言：
由于自然循环热水锅炉的大容量和对于断电保护、给水质量以及运行水平的低要求，它已经在中国广泛应用[1]。
然而，在上升管和下降管中工质的密度差过小可能会导致自然循环有效压力较低，如果结构不合理，将会产生爆管。
因此，在自然循环热水锅炉设计中，如何确定流动工质的安全速度和避免爆管导致受热面过冷沸腾是非常重要的。
在中国早期，有很多研究者致力于关于自然循环热水锅炉水动力计算的研究，一些人提出了对于几个简单循环回路和某些复杂循环回路的水动力计算方法，但是大多数方法只适用于简单回路。
西安交通大学的朱教授提出了一种应用计算机流体力学分析的方法，他将流动工质的特点和使用一种两端参考作为主动解决方法的直流循环原则做了比较。
这种方法的优势在于解决过程的方便性，但是对于复杂循环的解决过程非常复杂[2]。
自从上世纪七十年代，对于管流分布热力学模型的研究显著增多[3-8]。
目前，水动力计算方法使用“热水锅炉水动力计算法”[9](以下简称一般方法)，它提供了保证循环安全的一般方法。
该方法采用图解的方式确定介质的工作点，这是非常准确和高效的。
在解决整个问题时用到一些假设。
本文的目的是提供一种新的水动力数值计算方法，简称水动力回路分析法，即回路分析法。
本文的研究内容主要包括基本模型、基本原理、基本
方程及其可行性。
它使用分流的解决方法，这种方法更全面、准确和高效。
1模型研究
1.1基本模型
水动力计算的关键问题是获得在额定负荷下管中流动工质的特点[12-13]。
其中P1和P2分别是1-1和1-2处各自的压强，ρ是管中工质的平均密度，g是重力加速度，h是管子的高度，w是管内工质的流动速度，f是该管的的截面面积系数。
当工质从1-1处流向1-2处是，等式右边第二项的加号必须变为减号。
由于等式右边第二项的符号随流动工质的流动方向变化而改变，这是很难确定的。
此外，压力是速度的平方，所以这是一个非线性方程组。
为了克服上述的困难，这里介绍新的参数：
然后等式一与等式二变为：
其中E、U、G、R分别表示工质的动力、压力、流动率和流动阻力。
这两个方程类似于直流电路中电流的计算公式，单一管中有压力和阻力，单管等效图如图2所示。
在等式7中。
G是一个矢量，当工质从底部流向顶部时，G是正的，否则为负。
1.2回路分析法的基本原则
在回路分析法中，回路中的工质流量和分支中的工质流量被视为
未知量，方程根据工质压力的代数和为零的原则导出，即在循环回路中ΣU=0 和在循环中每个节点中流入的流量和等于流出的流量之和，即ΣG=0。
为了确保方程组有解，一个独立的回路必须被选为循环路径，并且工质在回路中的流动方向必须被确定。
顺着循环的方向，如果压力降低则为正，否则为负。
方程组通过计算机用迭代法求解[14-15]。
如果工质流量的计算结果是正的，则公职的流动方向与规定方向相同，反之则不同。
工质的流量和流动方向可以根据回路中工质的流量和流动方向确定。
以一个单回路循环为例，只包括一个上升管和一个下降管的单回路循环示意图如图3所示。
2结果与分析
2.1 计算实例
一个单回路的水动力特性采用一般方法和回路分析法进行分析，并且这两种方法采用相同的参数。
这个简单循环的结构如图3所示，结构参数列于表1，计算结果列于表2。
表1 结构参数
回路参数上升管下降管
总长/m 7 6
总高/m 5 5
热功率/kw 1000 1000
总阻力系数 2 1.5 管子直径/(mm*mm) 159*6 133*4 进口温度94 94
表2计算结果
方法质量流量（Kg/h）相对误差一般分析法25043 0.0559
回路分析法25057 ——
结果表明，在相同的参数下，因为相对误差很小，两种计算方法几乎是相同的。
因此。
回路分析法是正确的。
2.2 计算实践
在这一部分，用回路分析法和一般方法对一个具有自然循环的参数为
SHL7-1.0/115/70-AII的热水锅炉的水动力特性进行计算和分析，其结构参数、阻力系数、每个受热面的热负荷系数和计算结果都提供了参考[16]。
图4到图6分别显示的是工质在每个回路每个管中的流量曲线图，图7显示的是在对流回路中管中每个部分的流量曲线图。
表3分别列出了一般方法和回路分析法的计算结果。
图4到图7表明用回路分析法计算回路流量比较准确，并且过冷沸腾可以被直接检查出来，而一般分析法只能计算出管中工质的平均流量。
表3两种方法计算结果数据比较
方法前水冷壁
回路流量后水冷壁
回路流量
侧水冷壁
回路流量
对流循环
流量
流通率下降管进
口温度
一般法21600 23800 24100 196000 2.16 94.50
回路分析
法
21601 23850 24392 187916 2.10 93.66
相对误差0.0046 0.21 1.2 4.12 2.78 0.89 表3反映了水动力循环分析法和一般分析法的计算结果和计算出来的相对误差，循环回路的工质流量相对误差小于百分之五，流通率很小，并且下降管的进口温度非常低。
相对误差虽然小但是仍然存在，这有几个导致这个问题的原因。
首先，在一般分析法中，循环回路中的每个管子被视为相同的，这意味着每个管子是在相同的情形下而在回路分析法中每个管子在他们各自的工质状态下。
另一个原因是在回路分析法中，摩擦对流量的影响是分段考虑和计算的。
此外。
一般分析法中，必须用图解的方法来确定工作点，与回路分析法相比这更加不准确。
3总结
研究了一个单回路的水动力特性和发现了回路分析法的基本模型。
用
回路分析法和一般分析法计算和研究了自然循环热水锅炉的书动力特性，得到以下结论。
基本模型与直流电路中分流方法的模型相似，但是这个模型的关键点之一是方程组是非线性的。
两种方法的计算结果是相同的，表明了循环分析的正确性。
但是循环分析法考虑了影响每个管子流入总量和每个管子准确流量的因素。
此外，这种方法避免了用图解的方法来识别工质的工作点，因此它比一般分析法更准确一些。
回路分析法必须应用计算机来提高效率，因为手算求解方程组太复杂了。