传热传质外文翻译
《传热传质学》主要内容和专业词汇中英文对照
《传热传质学》主要内容和专业词汇中英文对照Chapter 1 Thermodynamics and Heat Transfer主要内容1.Concepts:heat (thermal energy)、heat transfer、thermodynamics、total amount of heat transfer、heat transfer rate、heat flux、conduction、convection、radiation2.Equations:1) The first law of thermodynamics (conservation of energy principle)2) Heat balance equation: a) closed system; b) open system (steady-flow)3) Fourier’s law of heat conduction4) Newton’s law of cooling5) Stefan-Boltzmann law主要专业词汇heat transfer 传热、热传递、传热学thermodynamics热力学caloric 热素specific heat 比热mass flow rate 质量流率latent heat 潜热sensible heat 显热heat flux热流密度heat transfer rate热流量total amount of heat transfer总热量conduction导热convection对流radiation辐射thermal conductivity 热导率thermal diffusivity 热扩散率convection/combined heat transfer coefficient 对流/综合换热系数emissivity 发射率absorptivity 吸收率simultaneous heat transfer 复合换热Chapter 2 Heat Conduction Equation主要内容3.Concepts:temperature field、temperature gradient、heat generation、initial condition、boundary condition、steady\transient heat transfer、uniform\nonuniform temperature distribution4.Equations:1) Fourier’s law of heat conduction (§2-1)2) Heat conduction equation (in rectangular\cylindrical\spherical coordinates)(§2-2、§2-3)3) Boundary conditions: (§2-4)a)Specified temperature B. C.b) Specified heat flux B. C. (special case: insulation、thermal symmetry);c) Convection B.C.d) Radiation B.C.e) Interface B.C.4) Average thermal conductivity k ave(§2-7)5) Solution of one-dimensional, steady heat conduction in plane walls、cylinders andspheres (k =const)：a) no heat generation, specified temperature B.C.: (§2-5)T(x) or T(r)；Q(x) or Q(r), Q=constb) with heat generation, Specified temperature B.C. or Convection B.C. : (§2-6)∆T max=T o-T s= gs2/2nk ; q(x)=gx/n; T s=T + gs/nhcharacteristic length S, shape factor n:plane walls — s = L (half thickness), n = 1cylinders ——s = r o, n = 2spheres ——s = r o, n =35.Methods: Solve a heat transfer problem1) Mathematical formulation (differential equation & B.C.)2) General solution of equation3) Application of B.C.s4) Unique solution of the problemtemperature field\distribution 温度场\分布 temperature gradient 温度梯度 heat generation 热生成(热源) initial\boundary condition 初始\边界条件 transient heat transfer 瞬态(非稳态)传热 isothermal surface 等温面 Heat conduction differential equation 导热微分方程trial and error method 试算法 iterate 迭代 convergence 收敛Chapter 3 Steady Heat Conduction主要内容6. Concepts:multilayer\composite wall overall heat transfer coefficient Uthermal resistance R t thermal contact resistance R ccritical radius of insulation R crfin efficiency fin effectiveness7. Equations:✓ Multiplayer plane wall 、cylinders and spheres: 12totalT T Q UA T R ∞∞-==∆& ✓ Fin: fin equation ——0)()(=--∞T T hp dxdT kA dx d c1) Uniform cross-section:2) Varying cross-section: )(fin fin max fin,fin fin ∞-==T T hA Q Q b ηη&&thermal resistance热阻parallel 并联in series串联thermal contact resistance 接触热阻composite wall 复合壁面thermal grease 热脂cross-section 横截面temperature execess 过余温度hyperbolic 双曲线的exponent 指数fin 肋(翅)片fin base 肋基fin tip 肋端fin efficiency 肋效率fin effectiveness 肋片有效度Chapter 4 Transient Heat Conduction主要内容8.Concepts:lumped system analysis characteristic length (L c=V/A)Biot number (Bi=hL c /k) Fourier number ( τ = at/L)9.Equations:●Bi≤0, lumped system analys is (§4-1)●Bi>0, Heisler/Grober charts OR analytical expressions1-D：a) infinite large plane walls, long cylinders and spheres (§4-2)b) semi-infinite solids (§4-3)multidimensional: product solution (§4-4)主要专业词汇lumped system analysis 集总参数法characteristic length 特征长度（尺寸）dimension 量纲nondimensionalize 无量纲化dimensionless quantity 无量纲量semi-infinite solid 半无限大固体complementary error function 误差余函数series 级数production solution 乘积解Chapter 5 Numerical Methods in Heat Conduction主要内容10.Concepts:control volume (energy balance) method、finite difference method、discretization、node、space step、time step、mesh Biot number、mesh Fourier number、mirror image concept、explicit/implicit method、stability criterion (primary coefficients ≥0)Numerical error: 1) discretization/truncation error; 2) round-off error11.Methods:Numerical solution:1) Discretization in space and time (∆x, ∆t);2) Build all nodes’ finite difference formulations (including interior and bou ndary nodes);i.Finite difference methodii.Energy balance method (i.e. Control V olume method)3) Solution of nodal difference eqs. of heat conduction;a)Direct method: Gaussian Eliminationb)Iterative method: Gauss-Seidel iteration主要专业词汇control volume 控制容积finite difference有限差分Taylor series expression泰勒级数展开式mirror image concept 镜像法Elimination method 消元法direct/iterative method 直接/迭代方法explicit/implicit method 显式/隐式格式stability criterion 稳定性条件primary coefficients 主系数unconditionally 无条件地algebraic eq. 代数方程discretization/truncation error 离散/截断误差round-off error 舍入误差Chapter 6、7 Forced Convection and Natural Convection主要内容12.Concepts:Nu、Re、Gr、PrForce/natural convection、external/internal flow、velocity/thermal boundary layer flow regimes、laminar/turbulent flowhydrodynamic/thermal entry region、fully developed regionCritical Reynolds Number (Re c)、hydraulic diameter (D h)、film temperature (T f)、bulk mean fluid temperature (T b)logarithmic mean temperature difference ( ∆T ln)volume expansion coefficient (β = 1/T)effective thermal conductivity (K eff = K Nu)evaporation、boiling、condensation、nucleation sitepool/flow boiling、subcooled / satuated boilingnatural convection / uncleate / transition /film boilingburn out point13.Equations:Drag force ：F D = C f AρV2/2Heat transfer rate：Q = hA(T s-T∞)3．Typical Convection Phenomena:1) Forced convection：external flow——flow over flat plates (§6-4)——flow across cylinders and spheres (§6-5)internal flow——flow in tubes (§6-6)2) Natural convection：flow over surfaces (§7-2)flow inside enclosures (§7-3)3) Boiling Heat Transfer主要专业词汇Force/natural convection 自然/强制对流laminar/turbulent flow 层/湍流boundary layer 边界层laminar sublayer 层流底层buffer layer 缓冲层transition region 过渡区flow regimes 流态inertia/viscous force 惯性/粘性力shear stress 剪切应力friction/drag coefficient 摩擦/阻力系数friction factor 摩擦因子dynamic/kinematic viscous 动力/运动粘度wake 尾流stagnation point 滞止点flow separation 流体分离vortex 漩涡rotational motion 环流velocity fluctuation 速度脉动hydrodynamic 水动力学的hydraulic diameter 水力直径fully developed region 充分发展段volume flow rate 体积流量arithmetic/logarithmic mean temperature difference 算术/对数平均温差volume expansion coefficient 体积膨胀系数interferometer 干涉仪asymptotic渐近线的effective thermal conductivity 有效热导率evaporation 蒸发boiling 沸腾condensation 凝结pool boiling池内（大容器）沸腾flow boiling（管内）强制对流沸腾subcooled / satuated boiling 过冷/饱和沸腾nucleation site 汽化核心uncleate / transition /film boiling 核态/过渡/膜态沸腾burnout point烧毁点surface tension 表面张力vapor bubble 汽泡excess temperature 过热度thermodynamic equilibrium 热力平衡phase change/transformation 相变latent heat of vaporization 汽化潜热analogical method 类比法integral approach 积分近似法order of magnitude analysis 数量级分析法similarity principle 相似原理Chapter 9 Radiation Heat Transfer主要内容14.Concepts:black body、gray body、diffuse surface、emissive power (E)emissivity (ε)、absorptivity (α)、reflectivity (ρ)、transmissivity (τ)irradiation(G)、radiosity(J)、reradiating(adiabatic) surfaceview factor (F ij)、radiation network、space resistance、surface resistance radiation shieldgas radiation、transparent medium to radiation、absorbing and transmitting medium ws:Blackbody：(1) Planck’s distrib ution law(2) Stefan-Boltzmann’s law(3) Wien’s displacement lawGraybody：(4) Kirchhoff’s lawActual body：E (T) = ε E b(T) = ε σT4W/m2Gas：(5) Beer’s law3．Calculation:1) View factor：reciprocity/summation/superposition/symmetry Rulecrossed-strings method2) Radiation heat transfer：Radiation networkOpen system：between two surface (e.g. two large parallel plates)Enclosure：2-surface enclosure；3-surface enclosureRadiation shield主要专业词汇thermal radiation热辐射、quantum theory量子理论、index of refraction 折射系数electromagnetic wave/spectrum 电磁波/波谱、ultraviolet (UV) rays紫外线、infrared (IR) rays 红外线absorptivity 吸收率、reflectivity 反射率、transmissivity 透射率、emissivity (ε) 发射率(黑度)、specular/diffuse reflection 镜反射/漫反射irradiation (incident radiation) 投入辐射、radiosity 有效辐射spectral/directional/total emissive power单色/定向/总辐射力fraction of radiation energy 辐射能量份额(辐射比)、blackbody radiation function 黑体辐射函数view factor 辐射角系数、crossed-strings method交叉线法、reciprocity/summation/superposition/symmetry Rule相互/完整/和分/对称性net radiation heat transfer 净辐射热流量radiation network 辐射网络图、space/surface radiation resistance 空间/表面辐射热阻、reradiating surface重辐射面、adiabatic 绝热的radiation shield遮热板transparent medium to radiation辐射透热体、absorbing and transmitting medium吸收-透过性介质Chapter 10 Heat Exchangers主要内容16.Concepts:heat exchanger type---- double-pipe、compact、shell-and-tube、plate-and-frame、regenerative heat exchangerparallel/counter/cross/multipass flowoverall heat transfer coefficient (U) fouling factor (R f)heat capacity rate capacity rationlog mean temperature difference (ΔT lm)heat transfer effectiveness (ε)number of transfer units (NTU)17.Equations:1) heat balance eq.: Q = C h (T h,in - T h,out)=C c(T c,out - T c,in)2) heat transfer eq.: Q = UAΔT lm( LMTD method)or Q = εQ max = εC min (T h,in –T c,in) ( ε-NTU method) 3．Methods:1) LMTD Method：Select a heat exchangerKnown: C h、C c、3‘T’Predict: 1‘T’、Q、A2) ε-NTU Method：Evaluate the performance of a specified heat exchangerKnown: C h、C c、UA、T h,in、T c,inPredict: Q、T h,out、T c,out主要专业词汇double-pipe/compact/shell-and-tube/plate-and-frame/regenerative heat exchanger套管式/紧凑式/壳管式/板式/蓄热（再生）式换热器parallel/counter/cross/multipass flow 顺流/逆流/叉流/多程流area density 面积密度tube/shell pass 管程/壳程static/dynamic type 静/动态型baffle 挡板header 封头nozzle管嘴guide bar 导向杆porthole 孔口gasket 垫圈lateral 侧面的/横向的fouling factor 污垢因子heat capacity rate 水当量heat transfer effectiveness (ε) 传热有效度number of transfer units (NTU) 传热单元数《传热传质学》知识难点与重点Chapter 1 Thermodynamics and Heat Transfer第一章热力学与传热学1．传热学研究内容（温差=>传热）；Heat Transfer Research (Temperature Difference=> Heat Transfer)2.三种基本传热方式的机理和基本公式；The Mechanisms and Basic Formulas of Three Basic Modes of Heat Transfer.3.传热过程、传热方程式；Heat Transfer Process，Heat Transfer Equation4.导热系数、对流换热系数、传热系数的物理涵义、单位、基本数量级、影响因素和变化规律；Physical meanings ,units, fundamental orders,influencing factors and changes in laws of heat conduction coefficient，convection heat transfer coefficient，heat transfer coefficient.5.热阻与热流网络图；Thermal resistance and heat transfer network6,单位与单位制；Unit and system of unitsChapter 2 Heat Conduction Equation第二章导热方程式1.导热问题的求解目标（物体内部的温度场与热流场）；Determine Target of Heat Conduction(temperature field and heat field in the internal objects)2.温度场（稳态、非稳态、均匀、一维、二维、三维）；Temperature field （steady,transient,uniform,one-dimensional,two-dimensional,three-dimensional）3.等温面、等温线、热流线的性质及相互关系；Properties of isothermal surface, isotherm,heat flow and the relationship among them 4.方向导数、梯度的数学概念及相互关系；Mathematical concept of directional derivative , gradient and the relationship between them5.Fourier 定律；Fourier Law6.推导导热微分方程式的理论基础、简化假设及方程各项（内能、导热、内热源、导温系数、）的物理涵义；Theoretical bases of concluding heat conduction differential equation,simplified assumption and physical meanings of each term in the equation (Internal energy, heat conduction, internal heat source,temperature transfer coefficient, )7.定解条件【几何、物理、时间、边界（Ⅰ、Ⅱ、Ⅲ）】Conditions of determining the solution【geometry,physics,time,boundary(Ⅰ、Ⅱ、Ⅲ )】8.导热问题的求解方法（解析解、数值解）。
传热传质 英语
传热传质英语Heat and mass transfer, also known as transport phenomena, is a discipline that studies the transfer of heat, mass, and momentum in various physical systems. It plays a crucial role in many fields, including engineering, physics, chemistry, and environmental science.Heat transfer focuses on the study of the transfer of thermal energy, including conduction, convection, and radiation. Conduction occurs when heat is transferred through solid materials, while convection involves the movement of fluids and the transfer of heat. Radiation is the transfer of heat through electromagnetic waves. Understanding heat transfer is essential for designing efficient heating and cooling systems, engines, electronics, and energy conversion devices.Mass transfer, on the other hand, deals with the movement and transport of substances or chemicals in different phases. It includes diffusion, convection, and phase change processes. Diffusion occurs when substances move from a region of higher concentration to a region of lower concentration. Convection is also involved in mass transfer when fluids carry substances. Phase change processes, such as evaporation and condensation, play a significant role in mass transfer. Mass transfer is important in areas like chemical engineering, environmental science, and biological systems.Together, heat and mass transfer form the foundation of transport phenomena. They are intricately interconnected and influence each other in many processes. For example, in heat exchangers, both heat and mass transfer occur simultaneously as fluids exchange heat and substances. In chemical reactors, the rates of chemical reactions are often governed by heat and mass transfer.Understanding and predicting heat and mass transfer is crucial for engineers and scientists to optimize processes, design efficient equipment, and develop sustainable technologies. By studying transport phenomena, we can improve energy efficiency, enhance separation processes, and develop novel materials and devices.。
化工专业英语第三篇翻译
Heat Transfer 传热Heat, as a form of energy, cannot be created or destroyed. Heat can be transferred from one substance to another.热是能量的一种形式,不能创造也不能消灭。
热可以从一个物体传递到另一个物体。
Heat always tends to pass from warmer objects to cooler ones. When a warm substance comes in contact with a cold substance, the molecules of the warm substance collide （碰撞） whth the molecules of the cold substance, giving some of its energy to the cold molecules. This is only one way to transfer heat.热总是倾向于从较热的物体向较冷的物体传递。
当一个暖的物体与一个冷的物体接触时，暖物体的分子与冷物体的分子碰撞，把他们的部分能量传给冷物体的分子。
这仅仅是传递热的一种方式。
In a chemical plant, for example, in a refinery （炼油厂）, transfer of heat is very important , the successful operation of most processes is dependent on correct application of the principles (原理) of heat transfer. Where we are handling （处理；加工；操纵） a hot material, we may insulate（隔离，绝缘） the system to hold the heat in; where the material is cold, we insulate to keep the heat out. Efficient equipment, designed to take full advantage of (充分利用) processing heat, is in use on almost all chemical plants.在化工厂，例如一个精炼厂，传热是非常重要的，大多数过程的成功运行取决于传热原理的正确运用。
传热和传质基本原理--传质理论 ppt课件
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（5） 温度对扩散系数的影响
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§3-6 流体和多孔介质中的扩散和扩散 系数
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多孔介质中的弥散传质 The origin of dispersion（弥散）
Physically, a non-constant advecting velocity
D f x c ~ j x u ~ ij)f jku ~ iu ~jfu ~ kc ~f
(*)
(1 C r)c ~ u ~ jf u x i jf u ~ ju ~ if( c x jfjk u ~ k c ~ f) 0
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Thus the last equation can be simplified as:
u j 0 x j
u ti xjuju i1 x p i xj
( u i uj) xj xi
c t xj
ujcxj
(Df xcj)
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Volume-averaged macroscopic GEs
u j f 0 x j
uif t
xj
ujf
uif
1pf
f xi
microscopic equations reads the spatial deviation: u~ j 0 x j
D D u ~i t xj(u ~juif u ~iu ~j)1f x ~ pi xj( x u ~ij u ~ xij)
化工原理英文教材传热传递Heat Transfer
Convection take places with conduction and radiation.
Heat transfer by conduction
Conduction is most easily understood by considering heat flow in homogeneous isotropic solids because in these there is no convection and the effect of radiation is negligible.
Basic law of conduction
The basic relation for heat flow by conduction is the proportionality between heat flux and the temperature gradient.
It can be written
Conduction and convection heat transfer rates depend upon temperature difference between two kinds of objects.
Radiation always happens except for temperature T=0 K.
dq k T dA n
(10-1)
The partial derivative calls attention to the fact that the temperature may vary with both location and time.
工程热力学与传热学(英文) 第8章 热量传递的基本方式
tf t
Φ
平壁上的对流换热
8-2-2 Newton’s law of cooling（牛顿冷却公式）
Ah(t w t f ) q h(t w t f ) ht
In 1701，by Newton
流动方向 u∞ u tw wall
t
f
t
Φ
平壁上的对流换热
A q A
dt dx
WW / m2源自Why the minus sign?
Where：
负号的含义
Heat is transferred in the direction of decreasing temp.
Φ — Heat- transfer rate（热流量） （单位时间通过给定面积传递的热量）W, kW
8-2 Convection Heat Transfer（热对流）
8-2-1 热对流和对流换热
1. Convection（对流） 是指流体各部分之间发生相对位移时，冷热流体相互 掺混所引起的热量传递现象。 2. Convection heat transfer（对流换热） 流体流过另一个物体表面时， 对流和导热联合起作用的热量 传递现象。 平壁表面的 传热机理
Heat Transfer
--- Chapter 8 Basic Modes of
Heat Transfer ---
Chapter 8 Basic Modes of Heat Transfer
Contents
Conduction heat transfer and Fourier’s law of onedimensional steady state heat-conduction Convection heat transfer and Newton’s law of cooling Radiation heat transfer and Stefan-Boltzmann Law Heat transfer processes
传热英文讲义-热对流 heat transfer-convection
ConvectionAs mentioned earlier, there are threemechanisms of heat transfer:conduction, convection, and radiation.Conduction and convection are similar inthat both mechanisms require materialmedium, but the difference is thatconvection requires the presence offluid motion. And heat transfer througha liquid or gas can be by convection orconduction, depending on if there ispresence of bulk fluid motion. In otherwords, if there exists bulk fluid motion,it is convection; if there is none, then itis conduction.Convection is complicated because itinvolves fluid motion and heatconduction. Thus, rate of heat transferby convection is higher than conduction.And the higher the fluid velocity, thehigher the heat transfer rate.Further reading about convection is available atAlthough, convection is complex, the rate of convection heat transfer is observed to be proportional to the temperature difference and can be conveniently expressed by Newton’s law of cooling asq conv=ℎ(T s−T∞) (W/m2) (x.1)orQ conv=ℎA s(T s−T∞) (W)(x.2)Whereh = convection heat transfer coefficient, W/m2·o CA s = heat transfer surface area, m2Ts = temperature of the surface, ˚CT∞= temperature of the fluid sufficiently far from the surface, ˚CConvection heat transfer coefficient h can be defined as the rate of heat transfer between a solid surface and a fluid per surface area per unit temperature difference. The convection coefficient is decided by variables influencing convection such assurface geometry, the nature of fluid motion, the properties of the fluid, and the bulk fluid velocity.Typical values of h are given in Table x.1.Table x.1Nusselt NumberIn convection studies, to nondimensionalise the governing equations, dimensionless numbers are introduced to reduce the number of total variables. Nusselt number, viewed as the dimensionless convection heat transfer coefficient is defined as:Nu=ℎL c kWhere k is the thermal conductivity of the fluid and Lc is the characteristic length. The physical significance means the heat transfer ratio of convection to conduction. For Nu=1, the heat transfer is pure conduction.Fluid flowsHeat transfer between moving fluid and solid surface or between moving fluid and interface (to/from air to falling drop).It is commonly assumed that all resistance to heat/momentum transfer occurs in boundary layer defined as part of fluid adjacent to the surface where velocity/temperature changes. Outside boundary layer velocity/temperature is constant.(a)Velocity boundary layerThe fluid flow is characterised by two regions:- Thin fluid layer (boundary layer) in which velocity gradients and shear stresses are large- Free stream (region outside boundary layer) where velocity gradients and stresses are negligible(b) Thermal (temperature) boundary layer- Thin fluid layer of fluid in which temperature gradients are large-exists only when there is a difference between surface temperature and bulk temperature Thickness of boundary layer δt is the value of y for which: Ts−TTs−T∞=0.99If the temperature distribution in boundary layer is known local heat flux from/to the surface can be calcul ated from Fourier’s law in the fluid (there is no fluid motion on the surface)q s′′=−k f∙ðTðy y=0 and q′′=ℎ∙(T s−T∞)In such case convective heat transfer coefficient can also be calculated (no need for experimental data or Buckingham theorem).Local heat transfer coefficientIntegrating local heat transfer coefficient over the entire surface the average value can be calculated:This method of calculation of heat flux to or from the surface is used in CFD packages (numerical solution of momentum and energy balance). In engineering calculations fully developed flows are usually considered therefore average heat transfer coefficients are commonly used (but not always).Structures of boundary layers, local/average heat transfer coefficients1.External flow(a). Flow parallel to flat plateLaminar part:-Local convective heat transfer coefficient:-average heat transfer coefficient ( integrate above from 0 to x):Turbulent part:-Local heat transfer coefficient:-Mixed boundary layer conditions (part of the plate laminar, part turbulent):(b). Flow around cylinderLocal heat transfer coefficient:Average:m and n are constants that can be found from literature.(c). Flow around sphere (similar to flow around cylinder)Internal flow:The extent of boundary layer can be estimated from Re numberD –Tube diameter [m], μ - dynamic viscosity [Pa s], m& - mass flow rate [kg/s],u m - mean fluid velocity [m/s]Thermal entrance regions:(a). Laminar flow:(b). Turbulent flow:Nu number for different types of flow:Fully developed laminar flow:(a). Constant temperature at the wall Nu D=3.66(b). constant heat flux at the wall Nu D=4.36Laminar flow including entry region:Fully developed turbulent flow (properties at T m)(a). Chilton-Colburn equation:(b). Dittus-Boelter equation:(c). Sieder-Tate equation:For noncircular tubes-hydraulic diameter D h=4A c/P, A c– flow crosssectionalarea, P –wetted perimeter (both in Re and Nu numbers)SummaryYou should:A) know/understand that convective heat transfer coefficients depends on:1. Type of flow: internal or external2. Geometry: flat plate, around cylinder/sphere, inside the pipe, etc3. Flow regime - Re number,B) be able to select appropriate correlation (from literature) for given flowconditions,C) be able to distinguish between local or average heat transfer coefficient.。
Chap 传热传质4.1 4.3
q q* ss kAs T 1 T2 / Lc
where the object’s characteristic length Lc is
Lc As / 4
1/ 2
(4.23)
(4.22)
• Exact and approximate results for common systems are provided in Table 4.1 (b). For example,
华中科技大学 力学系 传热传质学 2014 Spring
Flux Plots
Flux Plots
• Utility: Requires delineation of isotherms and heat flow lines. Provides a quick means of estimating the rate of heat flow. • Procedure: Systematic construction of nearly perpendicular isotherms and heat flow lines to achieve a network of curvilinear squares. • Rules: – On a schematic of the two-dimensional conduction domain, identify all lines of symmetry, which are equivalent to adiabats and hence heat flow lines. – Sketch approximately uniformly spaced isotherms on the schematic, choosing a small to moderate number in accordance with the desired fineness of the network and rendering them approximately perpendicular to all adiabats at points of intersection. – Draw heat flow lines in accordance with requirements for a network of curvilinear squares. • See Supplemental Section 4 S.1.
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传热传质(2011) 47:1077–1087DOI 10.1007/s00231-011-0772-1原文水泥砂浆的导热系数为空气相对湿度的函数´斯卡区思俊收到：2009.11.28 接受：2011.2.16 发表于：2011.3.4施普林格出版社2011 摘要本文是关于三水泥基砂浆的试验和研究结果。
起初,水分吸附被测量在20 c和六个相对湿度的空气水平上。
测试被完成吸附等温线得到的数学描述。
然后,热导系数k是测量与固定和不稳定的技术样本不同程度的水分。
一个线性关系之间系数k和材料水分测定。
组件的结果这两个阶段的研究帮助确定一个数学依赖的热电导系数上的相对湿度测试材料。
符号列表厘米水泥砂浆CLM水泥石灰砂浆MM改性砂浆米水含量样品(%)p蒸汽压(N /平方米)ps饱和蒸汽压(N /平方米)T温度(摄氏度)t时间(小时)w吸附水分(%)希腊符号你的空气相对湿度(%)k的热导系数(W /可)a . Siwin´斯卡·h·Garbalin´ska(&)部门的道路、桥梁和建筑材料,西波美拉尼亚的科技大学在什切青市,艾尔。
Piasto´w 50,70 - 311年,波兰什切青市电子邮件:Halina.Garbalinska@.pl1介绍一般来说,这里提供的方法对形式的导热系数之间的依赖在建筑材料和相对湿度结果作者提出的不是由其他研究人员。
研究适用于吸附在建筑材料进行了研究,以及那些关于热这两个电导率分裂成单独的问题。
一般而言,建筑材料吸附试验在于确定吸附物质量基于精确测量样品:前、中、后完成的测试。
通常的方式确定吸附品质是描述的标准[1]。
它的缺陷和实施一个新的方法(APM Augenblicksprofilmethode 或IPM瞬时剖面法)缩短了测量时间了Plagge,Funk,格林瓦尔德会战,Ha¨Scheffler推[2 - 5]。
在另一方面,Sparr和Wadso Markova,¨[6、7]显示一个创新技术的所谓微热量计,促进热力学特性的吸附过程。
一个通用方程的吸附等温线能描述令人满意的特性曲线所有的建筑材料在整个相对湿度范围是不可用的。
因此,所有的分析都下来了验证的方程可以在日益增长文学的主题[8 - 18]。
迫击炮的吸附的文中讨论的是主题进行研究这样的科学家如。
Janz[19],[20],埃斯皮诺萨Johannesson或卖[21]。
相当频繁的主题的研究和分析建筑材料的导热系数和影响各种因素,尤其是潮湿,在这个参数一些科学家把耦合传递热量andmoisture考虑在内,例如。
(22、23)。
然而,大多数的研究工作集中在负面影响的物质水分在导热系数。
这个导热系数之间的关系和材料水分是描述,尤其,得益于由吗分钟seok李[24],Salonvaara,Karagiozis,霍姆[25]或Ku¨nzel[26]。
通过Bobocin丩滑雪[27],指吸附和热导电率与含水量、进行在砂和灰细胞结合。
结果的研究证明,在吸附的依赖k水分可以近似作为一个折线组成的两个部分。
第一部分(吸附水分获得最高相对湿度为50%)特点是一个艾卡特角向x轴比第二部分(吸附水分获得在一个相对湿度超过50%)。
Osanyintola,Talukdar我西蒙森[13,28]分析了有效导热系数对杉木胶合板在不同的水分含量,使用HFMA(热流计设备)根据ASTM标准C518(2003)。
这个keff之间的依赖和相对湿度系数你确定他们的表单:keff =一个吗?布鲁里溃疡?的忍耐力?du3,a,b,c,d是确定的系数在个人的测量。
导热系数与含水量也检查C。
丩erny,Zuda,Drchalova丩,托曼,Rovnan。
丩-丩皮,拜耳(29岁)在宽光谱的吸湿与设备ISOMET2104水分。
用相同的装置进行了测试丩米列克,Jir.ic。
丩皮,Pavl。
丩k、C。
丩erny展示了他们结果在他们的工作[30]。
在文献[31],Jir.ic。
丩皮和C。
丩erny提供他们的研究成果在热,水分相关参数的矿棉的基础材料。
对于这种材料,他们确定一个等温吸附线在20 c为八层的吸附水分。
测试热电导率,展开了ISOMET2104进行了25摄氏度在干燥、湿润(相对湿度95%)和被水浸透的材料。
至于吸附水分的样品(从u = 0%,u = 95%)而言,科学家没有观察到任何不同的依赖之间k和水分。
一个显著高于中k值是观察到被水浸透的材料。
评估和水分相关品质。
热绝缘材料的麻木房子是进行工作[32]。
在他们的研究中,Valovirta和Vinha专注于麻松散的形式和三种类型绝缘垫。
对于这些材料,吸附等温线在五个不同的吸附水分的水平,k系数在四个温度(-10、0、10、20 c)和三个水分水平(u = 33,65,86%)的方式确定HFMA(热流计装置),以及热传输指数,建立了使用calibratedheating箱。
试验结果证实了规则中k值一起成长成长的水分和温度。
热、湿度相关素质的许多(37)受欢迎的建筑和绝缘材料也被评估由达山•库玛在他的论文[33]。
在许多参数实验确定确定达山•库玛吸附等温线和k系数。
测量热导,他使用一个面板装置与一个屏蔽加热板和HFMA(热流计装置)。
这个作者提出了示范试验结果为加气混凝土。
测试了在加热板温度31.51 c和冷却板温度9.75 c。
对于测量吸附,样品是大小40 9 40 9 20毫米(8个人电脑进行测量u = 100%,T = 22 c)和40 9 40 9 6毫米(3个人电脑以u = 88.1;71.5;0.6%,T = 23 c)。
当测试混凝土、水泥砂浆、水泥灌浆,[34]的作者把很多因素考虑。
他们专注于年龄、w / c比值,类型的外加剂,总分数大小、细骨料分数、温度和水分的材料。
作者应用以下研究方法:TLPP(two-linear-parallelprobe方法),小灵通(平面热源法),计(热看守板法)。
试验结果表明,混凝土的导热系数基本上取决于在它的总分数大小和水分。
与此同时,热导率的水泥砂浆和灌浆转身更依赖于w / c比值和类型的掺合料。
研究人员检查了也影响年龄的硬化水泥浆、砂浆和混凝土的k系数,进行他们的测试后3、7、14和28天的养护。
这是观察到,固化时间并没有改变电导率多除了非常早期的阶段。
一个评估的影响玻璃纤维掺合料来水泥砂浆在它的热量和水分的相关参数是提供工作[35]。
对于他们的测试,radska 颇得吗?托曼,Drchalova吗?Totova吗?和C ? erny ?使用ISOMET104。
水/水泥比在他们的迫击炮是0.3。
三个不同内容的迫击炮,大量的玻璃纤维和其他外加剂检测。
一个重要的外加剂的影响在减少k是观察。
上面的介绍研究工作开展的不同的中心,提供证据的一个广泛的分析导热问题相关的建筑材料。
基本上,他们参考评估的影响个人因素对导热系数的值系数为各种建筑材料。
此外,他们也呈现出多样性的应用研究方法。
轴承上述和呈现在文学实验和分析想法,作者决定做一个实验,结合前两个讨论研究模块,即:测试水分的sorptionand测量导热系数,这是由应用程序的固定吗和不稳定的技术。
水泥基砂浆是作为材料进行测试。
结果和最终确定导热之间的依赖和相对湿度如下为每个测试材料。
之间的依赖导热的建筑材料及其水分有或多或少的线性字符。
然而,应用程序的这个简单的线性关系带来特定的困难在实践中,特别是,如果我们处理一个多层分区。
自然地,如果我们有一个计校准精确(取决于温度、湿度、水化程度等)对于一个给定的材料在一方面,我们能够确定材料水分的样本。
在实验室条件下,它不造成严重的问题,当我们可以测试所有的材料另外。
它将成为麻烦,但是,如果我们必须达到所有个人材料层,形成一个吗多层建筑分区。
此外,在实际工程计算,我们不依赖的价值观材料健康,但在参数来描述要么蒸汽压力或所谓的绝对湿度(包括指水蒸气的毛孔中包含的材料)。
蒸汽压力之间的关系在一个给定的温度和含水量是表达的吸附等温线与课程具体(最频繁、强烈非线性)为每种材料。
考虑到这一点,它被认为是必要的尝试重建一个功能依赖之间的热电导系数k的多孔材料,其水内容w、相关与等温吸附线对环境热和水分条件。
下面是一个解决方案的提出所以制定的问题,作为一个例子,三个水泥基砂浆。
2测量2.1吸附测量这个命题的功能依赖k(u)要求一个三级的解决问题的办法。
首先,关系在参数定义空气湿度和水含量材料w(u)检查和描述。
然后,通过实验,热导率系数在不同水分的材料确定和数学描述的与水有关的可变性的这个参数k(w)的建议。
最后,两个函数依赖被合并成一个数学符号k(u)。
进行了测量三个水泥基砂浆用下面的内容在1 dm3:吗?水泥砂浆厘米:水泥490克,水270克,砂1519克,吗?改性砂浆MM:水泥490克,水270克,砂1519克,聚丙烯纤维长约3毫米,0.9克,吗?水泥石灰灰浆CLM:水泥、石灰194克194克,水336克,砂1164 g。
测量了两个独立的实验模块。
首批的测量水吸附[1]20 c和六水平的相对湿度的空气(u & 11,33岁,54岁,75年,85年,98%)。
温度维持在所需的水平,一室吗恒温器,而稳定的相对湿度是由于饱和水解决方案获得的吗适当的盐:LiCl(u & 11%),MgCl2(u & 33%),Mg(硝态氮)2(u & 54%)、氯化钠(u & 75%)、氯化钾(u和85%),K2SO4(u & 98%)。
样品,绝缘在侧表面和干到固体,被放置在紧容器与一个预定义的空气相对湿度(图1),和这容器放入气候室用稳定的温度(图1 b)。
在恒温箱,在每个紧容器,有三个样品给灰浆,大小10 9 6 9 1厘米。
平均体积密度,决定指定用于吸附测试样品,如下:对于水泥砂浆?。
066克/立方厘米,对修改后的砂浆?。
020克/立方厘米,和水泥石灰灰浆吗?1.737克/立方厘米。
的吸附测量包括在记录每个样品的质量变化,而在每一个时间,54样品重[36]。
间隔称重吗?梕初非常6、8、12 h梬随着时间延长到7天。
测量进行了直到达到水分平衡在所有样本存储在鉴于热水分条件。
达到平衡状态花了9个月。
水分含量的变化[%]Dm图1安排吸附测量:一个紧容器电网控股在hygrostatic样品溶液,乙一个气候室的测试材料的containerssamples对时间t[h] 课程的测试图的图表(无花果。
2、3、4)。
最强烈的吸附作用进行的初始阶段,或大约在第一个7天。
后来,只轻微的,但对许多个月伸出,增加的吸附相关的水分被观察到。