EXPERIMENTAL RESEARCH OF FLOW STRUCTURE IN A GAS-SOLID CIRCULATING FLUIDIZED BED RISER BY PIV
第一肝门血流阻断器的结构设计与性
第４１卷㊀第６期２０２２年㊀１２月北京生物医学工程ＢｅｉｊｉｎｇＢｉｏｍｅｄｉｃａｌＥｎｇｉｎｅｅｒｉｎｇＶｏｌ ４１㊀Ｎｏ ６Ｄｅｃｅｍｂｅｒ㊀２０２２基金项目：国家自然科学基金（５１４７５３０８）资助作者单位：上海理工大学医疗器械与食品学院（上海㊀２０００９３）通信作者：石更强㊂Ｅ⁃ｍａｉｌ：ｙｉｎｃｓｙ＠１６３．ｃｏｍ第一肝门血流阻断器的结构设计与性能研究石更强㊀尹帅帅㊀孙旭阳摘㊀要㊀目的腹腔镜手术难度大，手术过程常存在出血问题㊂为了控制血流速度，本研究设计了一款利用气囊阻断血流的阻断装置，可以在手术过程中将第一肝门完全扎紧㊂方法本文通过对现有阻断器结构的研究，设计了一种用于腹腔镜下阻断第一肝门的血流阻断器，利用流体使气囊膨胀，压缩血管外壁达到阻断血流的效果㊂结果通过方程计算和运用ＡＮＳＹＳ软件分析，气流流速达到８ｍ／ｓ时，流体运动状态最为均匀㊂利用伯努利方程，计算得出阻断所需要的压力㊂搭建实验装置，进行体外模拟实验，模拟肝门静脉被阻断过程，对阻断效果进行可用性评价㊂结论本文设计的血流阻断装置可以对血管有很好的阻断效果㊂关键词㊀第一肝门；血流阻断；结构设计；参数计算；模拟实验ＤＯＩ：１０ ３９６９／ｊ．ｉｓｓｎ．１００２－３２０８ ２０２２ ０６ ０１１．中图分类号㊀Ｒ３１８ ０１㊀㊀文献标志码㊀Ａ㊀㊀文章编号㊀１００２－３２０８（２０２２）０６－０６１６－０７本文著录格式㊀石更强，尹帅帅，孙旭阳．第一肝门血流阻断器的结构设计与性能研究［Ｊ］．北京生物医学工程，２０２２，４１（６）：６１６－６２２．ＳＨＩＧｅｎｇｑｉａｎｇ，ＹＩＮＳｈｕａｉｈｓｕａｉ，ＳＵＮＸｕｙａｎｇ．Ｓｔｒｕｃｔｕｒａｌｄｅｓｉｇｎａｎｄｐｅｒｆｏｒｍａｎｃｅｏｆｔｈｅｆｉｒｓｔｈｅｐａｔｉｃｐｏｒｔａｌｂｌｏｏｄｆｌｏｗｂｌｏｃｋｅｒ［Ｊ］．ＢｅｉｊｉｎｇＢｉｏｍｅｄｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，２０２２，４１（６）：６１６－６２２．ＳｔｒｕｃｔｕｒａｌｄｅｓｉｇｎａｎｄｐｅｒｆｏｒｍａｎｃｅｏｆｔｈｅｆｉｒｓｔｈｅｐａｔｉｃｐｏｒｔａｌｂｌｏｏｄｆｌｏｗｂｌｏｃｋｅｒＳＨＩＧｅｎｇｑｉａｎｇ，ＹＩＮＳｈｕａｉｓｈｕａｉ，ＳＵＮＸｕｙａｎｇＳｃｈｏｏｌｏｆＭｅｄｉｃａｌＩｎｓｔｒｕｍｅｎｔａｎｄＦｏｏｄＥｎｇｉｎｅｅｒｉｎｇ，ＵｎｉｖｅｒｓｉｔｙｏｆＳｈａｎｇｈａｉｆｏｒＳｃｉｅｎｃｅａｎｄＴｅｃｈｎｏｌｏｇｙ，Ｓｈａｎｇｈａｉ㊀２０００９３Ｃｏｒｒｅｓｐｏｎｄｉｎｇａｕｔｈｏｒ：ＳＨＩＧｅｎｇｑｉａｎｇ（Ｅ⁃ｍａｉｌ：ｙｉｎｃｓｙ＠１６３ ｃｏｍ）ʌＡｂｓｔｒａｃｔɔ㊀ＯｂｊｅｃｔｉｖｅＬａｐａｒｏｓｃｏｐｉｃｓｕｒｇｅｒｙｉｓｄｉｆｆｉｃｕｌｔ，ａｎｄｔｈｅｒｅｉｓｏｆｔｅｎａｐｒｏｂｌｅｍｏｆｂｌｅｅｄｉｎｇｄｕｒｉｎｇｔｈｅｏｐｅｒａｔｉｏｎ．Ｉｎｏｒｄｅｒｔｏｃｏｎｔｒｏｌｔｈｅｂｌｏｏｄｆｌｏｗｖｅｌｏｃｉｔｙ，ｔｈｉｓｓｔｕｄｙｄｅｓｉｇｎｓａｂｌｏｃｋｉｎｇｄｅｖｉｃｅｂｙｕｓｉｎｇａｉｒｂａｇｔｏｂｌｏｃｋｔｈｅｂｌｏｏｄｆｌｏｗ，ｗｈｉｃｈｃａｎｆａｓｔｅｎｔｈｅｆｉｒｓｔｈｅｐａｔｉｃｈｉｌｕｍｃｏｍｐｌｅｔｅｌｙｄｕｒｉｎｇｔｈｅｏｐｅｒａｔｉｏｎ．ＭｅｔｈｏｄｓＩｎｔｈｉｓｐａｐｅｒ，ｔｈｒｏｕｇｈｔｈｅｓｔｕｄｙｏｆｔｈｅｅｘｉｓｔｉｎｇｓｔｒｕｃｔｕｒｅｏｆｔｈｅｂｌｏｃｋｅｒ，ａｋｉｎｄｏｆｂｌｏｏｄｆｌｏｗｂｌｏｃｋｅｒｆｏｒｔｈｅｆｉｒｓｔｈｅｐａｔｉｃｈｉｌｕｍｂｌｏｃｋｉｎｇｕｎｄｅｒｌａｐａｒｏｓｃｏｐｅｉｓｄｅｓｉｇｎｅｄ．ＲｅｓｕｌｔｓＴｈｒｏｕｇｈｅｑｕａｔｉｏｎｃａｌｃｕｌａｔｉｏｎａｎｄＡＮＳＹＳｓｏｆｔｗａｒｅａｎａｌｙｓｉｓ，ｔｈｅｆｌｏｗｖｅｌｏｃｉｔｙｒｅａｃｈｅｓ８ｍ／ｓ，ｔｈｅｆｌｕｉｄｍｏｖｅｍｅｎｔｓｔａｔｅｉｓｔｈｅｍｏｓｔｕｎｉｆｏｒｍ．Ｂｅｒｎｏｕｌｌｉｅｑｕａｔｉｏｎｉｓｕｓｅｄｔｏｃａｌｃｕｌａｔｅｔｈｅｐｒｅｓｓｕｒｅｒｅｑｕｉｒｅｄｆｏｒｔｈｅｂｌｏｃｋｉｎｇ．Ｔｈｅｅｘｐｅｒｉｍｅｎｔａｌａｐｐａｒａｔｕｓｉｓｓｅｔｕｐｔｏｓｉｍｕｌａｔｅｔｈｅｐｒｏｃｅｓｓｏｆｈｅｐａｔｉｃｐｏｒｔａｌｖｅｉｎｂｅｉｎｇｂｌｏｃｋｅｄｉｎｖｉｔｒｏ，ａｎｄｔｈｅｕｓａｂｉｌｉｔｙｏｆｔｈｅｂｌｏｃｋｉｎｇｅｆｆｅｃｔｉｓｅｖａｌｕａｔｅｄ．ＣｏｎｃｌｕｓｉｏｎｓＴｈｅｄｅｓｉｇｎｅｄｂｌｏｏｄｆｌｏｗｂｌｏｃｋｉｎｇｄｅｖｉｃｅｃａｎｈａｖｅｇｏｏｄｂｌｏｃｋｉｎｇｅｆｆｅｃｔｏｎｂｌｏｏｄｖｅｓｓｅｌｓ．ʌＫｅｙｗｏｒｄｓɔ㊀ｆｉｒｓｔｈｅｐａｔｉｃｈｉｌｕｍ；ｂｌｏｏｄｉｎｆｌｏｗｏｃｃｌｕｓｉｏｎ；ｓｔｒｕｃｔｕｒｅｄｅｓｉｇｎ；ｐａｒａｍｅｔｅｒｃａｌｃｕｌａｔｉｏｎ；ｓｉｍｕｌａｔｉｏｎｅｘｐｅｒｉｍｅｎｔ０㊀引言肝脏肿瘤一直是常见的多发疾病，需要进行肝脏切除手术达到治疗的效果［１］㊂在手术过程中，切割肝脏组织经常会伴随不同程度的出血，出血量的多少直接影响着术后并发症的发病率以及病死率［２］㊂腹腔镜肝切除手术更是注重术中出血的问题，因为手术过程中，操作空间的限制导致视野不够清晰，无法直观地进行手术，只能通过屏幕影像来进行操作，也就不能采用常规的方法进行止血［３］㊂如何控制腹腔镜手术中的出血问题也就成了一个更加严峻的问题㊂在腹腔镜手术过程中，如果能够有效减少术中出血问题，那么手术治疗的病症范围也会相应扩大，成功率也就越高㊂因此，设计一个可以在腹腔镜手术过程中减少出血甚至阻断出血的装置具有重大的意义㊂目前，国内外腹腔镜肝门血流阻断器都还处在刚起步阶段，没有成熟的产品技术，都是依赖于开腹手术所使用的措施进行阻断，采用了一些简易的道具在手术中使用㊂市场上利用一些断肝的器械进行适当的止血［３］，比如微波刀㊁氩气凝血器㊁超声刀㊁腹腔镜下多功能手术解剖器等㊂这些断肝器械大部分都是通过电能产生的高温将断面进行瞬间结痂达到止血的目的，只能进行局部的控制，无法做到根本上的血流阻断，并且大部分操作都是需要在开腹手术的环境下才能够顺利进行，依旧会影响手术进程㊂因此，利用第一肝门位置的特殊性，设计一种阻断装置，将第一肝门进行根本性的血流阻断，提高腹腔镜手术的成功率，是本研究的重点㊂课题组结合腹腔镜肝脏临床手术，设计了一款第一肝门血流阻断装置，这种填充式阻断器利用了流体进入气囊产生的压力，使得气囊发生迅速膨胀，挤压血管空间来达到阻断的效果㊂并且利用流体力学计算出装置所需要的动力压强，通过能量守恒方程㊁动量守恒方程等推导计算，再结合ＡＮＳＹＳ软件分析，计算出了所需要的流体流速㊂最后通过体外模拟实验，模拟血管以及血液在正常与被阻断条件下的流动状态，来实现对装置可行性的评价㊂１㊀血流阻断装置本文通过对现有血流阻断器结构的研究，设计出一种填充式血流阻断器㊂这种填充式阻断器利用了流体进入气囊产生的压力，使得气囊发生迅速膨胀，挤压被环绕的血管空间来达到阻断的效果㊂这种方式相对于普通的阻断带，利用材料自身的性质进行挤压，在方法上有了很大的改进㊂气囊阻断带是利用流体的压强来作用，施加压力的过程平缓，可调空间大，并且材料所使用的都是弹性较好的柔性材料，减少了材料对人体的直接损害㊂１ １㊀第一肝门血流阻断器整体设计在秉持操作便捷㊁结构简单安全㊁可控性强的设计原则，并且能够有效减少甚至阻断腹腔镜手术中的出血问题，设计了血流阻断器，同时为了便于通过穿刺进入人体内，课题组将阻断器的气体传导装置设计成柱状㊂第一肝门位于肝脏右下部，从穿刺部位到肝门的距离为１０ １５ｃｍ，而穿刺的最大直径为１２ｍｍ，因此本文在设计的过程中，要保证装置能够顺利进入人体，那么直径就不能超过１２ｍｍ㊂为了保证实物能够有效起作用，将直径设为１２ｍｍ，进入穿刺的外套管设为１５ｍｍ，整体结构图如图１，零件图如图２㊂图１㊀血流阻断器结构图Ｆｉｇｕｒｅ１㊀Ｄｉａｇｒａｍｏｆｔｈｅｆｌｏｗｂｌｏｃｋｅｒｓｔｒｕｃｔｕｒｅ图２㊀血流阻断器零件图Ｆｉｇｕｒｅ２㊀Ｐａｒｔｄｒａｗｉｎｇｏｆｔｈｅｆｌｏｗｂｌｏｃｋｅｒｓｔｒｕｃｔｕｒｅ１ ２㊀血流阻断器结构构成１ ２ １㊀动力装置血流阻断器的动力装置采用的是球囊，由橡胶球囊以及控制阀和单向阀组成㊂球囊前后各有一个连接孔，一端用来连接单向阀保持与大气的连通，另一端则是通过控制阀与输气管连接㊂单向阀保证了㊃７１６㊃第６期㊀㊀㊀㊀㊀㊀石更强，等：第一肝门血流阻断器的结构设计与性能研究气体的稳定输入，通过挤压球囊获得气体，松开以后球囊又会因为大气压自动恢复，省去了储气（液）这一步，更加方便快捷㊂控制阀控制气体的流向以及能够排出多余的气体，使得进入装置的气体不会回流，直接能够控制内部压力的平衡㊂球囊良好的恢复性是动力装置的重要特性，这方便进行反复操作直至达到血管阻断的效果㊂１ ２ ２㊀传导装置传导装置在进入人体后，会随着内部器官的变化发生一定的位移，因此装置自身需要有很好的固定效果才能在手术中起到不错的作用㊂设计的传导装置主要由螺纹盖㊁外套管㊁导管㊁固定件以及弹簧组成㊂外套管作为导管的载体，通过穿刺将导管等部件送入人体内部，螺纹盖与外套管之间相互配合，能够有效减少固定件与导管的位移，使他们位置相对固定㊂导管作为主要部件，一端与动力装置通过橡胶管连接，采用多段圆台状连接，利用橡胶的摩擦力紧密相连，另一端与进入体内的气囊连接并为其提供动力㊂固定件比导管稍短，下方有一个与外套管相同的凹槽，通过两个凹槽的错位能够对气囊的自由端进行固定㊂两个弹簧是为了起到自动恢复位置的作用，分别放置在导管和固定件的下方㊂１ ２ ３㊀多孔软胶气囊多孔气囊采用了软胶的材料，能够形成对目标位置的包绕，满足正常温度下的工作环境㊂而气囊外层则是一层受压易膨胀的医用橡胶，当内部产生气压，通过多孔将气体导出，医用橡胶的阻隔使得自身发生膨胀，体积逐渐增加，减小被包绕部位的空间，达到阻断血流的目的［４］㊂医用软胶的材料也有着更加安全可靠的特点㊂１ ３㊀血流阻断器的工作原理在手术之前，通过穿刺将阻断器前端推进人体，然后利用自身的硬度穿过第一肝门进行环绕，用手术钳从另一端将端头取出并放入外套管的缺口处，然后将压住的固定件放开，通过弹簧恢复自身形变，自动锁住端头达到包绕的效果㊂最后回拉导管到合适位置，使用固定阀进行固定，术前准备即完成㊂当需要进行阻断的时候，用气囊进行加压即可达到阻断血流的作用，并且通过单向阀可以做到实时控制血流的通畅与阻断，方便手术过程中的调控㊂２㊀装置控制参数设定２ １㊀速度设定用手挤压球囊产生气体，通过传导装置进入多孔气囊，多孔气囊通过各个孔径，将气体输送到外部可形变的橡胶膜㊂由于孔径的位置不同，所产生的气体流速大小也不同，流速的不同导致橡胶模的形变不同，因此需要一个合适的流速，既要保证内部流体运动的稳定，也要能够让流体均匀地向各个孔流出㊂流体运动过程的复杂性，决定了计算的复杂性，在基于能量守恒㊁动量守恒㊁质量守恒的基本方程下，利用ＡＮＳＹＳ软件，对流体的流速进行计算分析㊂预处理：假定流体为不可压缩流体㊂流体的运动形式可以用雷诺数Ｒｅ进行标定，一般的Ｒｅ＜２０００为层流，Ｒｅ值在２０００ ４０００之间的为过渡态，Ｒｅ＞４０００为湍流㊂在ＡＮＳＹＳ中，选用的湍流方程模型为标准模型㊂选用计算流体动力学（ｃｏｍｐｕｔａｔｉｏｎａｌｆｌｕｉｄｄｙｎａｍｉｃｓ，ＣＦＤ）［５］对通过气囊以及各出口的流体分散过程进行分析，分析在不同速度下气囊内空气运动状态所产生的变化㊂最后得到在不同速度下的运动矢量图，其中在８ｍ／ｓ时，可以看到整体运动趋势最接近，有利于气体的填充，满足装置的速度要求㊂通过流体动力学方程并结合ＡＮＳＹＳ软件分析，当流速达到８ｍ／ｓ时，流体在通过气孔的流动效果最好，该流速对多孔气囊的填充效果最好㊂２ ２㊀输出压强设定流道内的气体流速主要由动力装置提供的压强决定，压强越大，流速越大，通过采用伯努利方程分析计算，计算动力装置的输出压强，确保进入多孔气囊的各个孔的流速相对稳定㊂气流在流过传导装置的过程中，会由于气流与装置内壁的摩擦及管道结构的变化引起气压的降低㊂因此，要通过流体力学计算这部分压降，通过提高输出端的压强来弥补这部分损失㊂预处理：假定空气为不可压缩的理想气体，环境为第一肝门的特殊环境，动力装置内外初始压力都为大气压１ＭＰａ，在此条件下对内部流体进行力学计算，图３为装置简化通道㊂利用伯努利方程计算：㊃８１６㊃北京生物医学工程㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀第４１卷图３㊀流体通道简化Ｆｉｇｕｒｅ３㊀ＦｌｕｉｄｃｈａｎｎｅｌｓｉｍｐｌｉｆｉｃａｔｉｏｎｄｉａｇｒａｍＺ１＋Ｐ１ρｇ＋α１ｖ２１２ｇ＝Ｚ２＋Ｐ２ρｇ＋α２ｖ２２２ｇ＋Δｈ（１）㊀㊀式中：Ｚ１㊁Ｚ２是进出口的高度；Ｐ１㊁Ｐ２是进出口压力；α１㊁α２是速度修正系数；ｖ１㊁ｖ２是进出口速度；Δｈ是全程压强损失；ρ是流体密度；ｇ为重力加速度㊂全程压降损失ΔＰ＝ρｇΔｈ＝２８６ ０５Ｐａ，取常态下大气压（即装置外部压力）Ｐ２＝１ ０１３ˑ１０５Ｐａ，最后计算得出动力装置初始压力需要达到１ ０１６ˑ１０５Ｐａ㊂由于每次加压以后，内部压强都会得到提升，因此在装置使用过程中，后续的输出需要持续增压，每次不得低于２８６Ｐａ才能够实现不断地注入气体，才能保证流体的流速相对稳定㊂２ ３㊀血流阻断压强计算前文已经计算出了动力装置提供的初始压强，并且也计算出了每次需要比前一次多增加的压强，为了达到阻断肝门的效果，不可能无限制地一次次加压，为了后续给该设备的操作者一个阻断压强的预估，并且防止损害血管，本文进行了第一肝门阻断压强的计算㊂阻断第一肝门也就是需要重点阻断肝门静脉以及肝动脉［６］㊂肝门静脉与肝动脉的血液流动过程中，需要通过外力的阻断，达到降低血液流速的作用，肝脏手术过程中不需要达到完全阻断，只要使得血液流速有明显的下降即可，有少量的血液流通并不会影响阻断的效果㊂肝动脉直径约为２ ５ｍｍ，其中血液流速约为０ １９ｍ／ｓ，由此可见其中的压降小于肝门静脉，因此在阻断压力大小计算上，直接选取肝门静脉所需要的阻断压力即可，在阻断肝门静脉的同时也能阻断其他相对稍小的血管㊂预处理：将血液看成不可压缩的流体，建立肝门流动模拟图，ｙ轴方向为血液流动方向，如图４㊂图４㊀肝门静脉流动模拟图Ｆｉｇｕｒｅ４㊀Ｓｉｍｕｌａｔｉｏｎｏｆｈｅｐａｔｉｃｐｏｒｔａｌｖｅｉｎｆｌｏｗ建立力平衡方程：ｆｙ－１ρ∂ｐ∂ｙ＋ν∂２νｙ∂ｘ２＋∂２νｙ∂ｙ２＋∂２νｙ∂ｚ２æèçöø÷＝∂νｙ∂ｔ＋∂νｙ∂ｘνｘ＋∂νｙ∂ｙνｙ＋∂νｙ∂ｚνｚ（２）㊀㊀式中：ｆｙ为血管压力；ρ为流体密度；∂ｐ为流体在该点的压力变化量；ｖ为流体速度；ｖｘ㊁ｖｙ㊁ｖｚ为各方向速度分量；ｔ为时间㊂经过一系列的推导计算可以求得压强的变化量Δｐ＝２７ ９Ｐａ㊂男性门静脉压力１６４０Ｐａ，因此阻断至少需要１６６７ ９Ｐａ的压强，男性门静脉血压稍高，能够达到阻断男性肝门静脉的压力也就能够阻断女性肝门静脉㊂因此操作者可以根据此预估值进行后续的加压操作，防止过度加压或者加压不足，对现实的实际操作具有指导意义㊂３㊀模拟实验为了更好地验证该装置的合理性，通过采用体外模拟实验，来证明此设计结构的合理性与实用性㊂验证血流阻断器的阻断效果最直接的办法就是通过模拟阻断器阻断相应的血管，观察血液流速的变化以及多孔气囊的膨胀情况，通过分析血液流速的大小和气囊的整体膨胀效果来判断是否能够满足手术中的情况㊂通过模拟血液的流动方式㊁血管的基本特征，对其施加以合理的压强来达到所需要的目的，从而有效评价该装置的合理性㊂３ １㊀实验平台构成模拟的实验平台包括铁架台，用来固定引流袋，㊃９１６㊃第６期㊀㊀㊀㊀㊀㊀石更强，等：第一肝门血流阻断器的结构设计与性能研究并调整引流袋的高度，提供不同的流速㊂引流袋用来盛装流体㊂硅胶导管用来模拟血管㊂玻璃转子流量计，用来计算流体的流速㊂还有设计的血流阻断器，模拟阻断效果㊂３ ２㊀实验材料选择（１）血液在体外易发生化学变化，导致一系列物化性质都会改变，经过一系列对比，选择和血液理化性质非常接近的牛奶作为替代品㊂牛奶的密度在１ ０３，比重平均为１ ０３２，相对黏度为３左右㊂（２）本实验是模拟阻断第一肝门，由于第一肝门主要包含了多个血管，因此实验选择模拟的是其中流量最大的，所以选用直径最大的门静脉去模拟实验㊂门静脉的直径约６ １０ｍｍ，外壁的厚度约为１ｍｍ，实验中选用直径为８ｍｍ，外壁厚度为１ｍｍ的硅胶导管作为血管的体外替代品㊂１５００ｍＬ引流袋，用来盛放流体，通过控制出口的阀门来控制血液流量㊂如图５为导管和引流袋㊂图５㊀硅胶导管和引流袋Ｆｉｇｕｒｅ５㊀Ｓｉｌｉｃｏｎｅｃａｔｈｅｔｅｒａｎｄｄｒａｉｎａｇｅｂａｇ（３）实验选用的流量计是玻璃转子流量计，如图６所示，玻璃转子流量计能够很直观地测出流体的速度㊂流体从下方流入，从上方流出，通过观察浮子的高度就可以读出流量的大小，从而利用连续性方程计算出流速的大小㊂根据门静脉的流量１ １Ｌ／ｍｉｎ，因此选用的是量程为１０ １００Ｌ的转子流量计㊂（４）铝合金铁架台，可以用来固定引流袋的高度㊂引流袋的下方连接硅胶导管模拟血管，调节引流袋的高度，利用重力势能为流体提供一定的速度㊂３ ３㊀实验步骤３ ３ １㊀实验装置搭建肝门静脉血压测量结果为１６５０Ｐａ左右，血液流速０ ２ｍ／ｓ㊂通过设计模拟血管的压强和流速，进行体外实验来检验装置的可行性㊂由肝门静脉血压图６㊀玻璃转子流量计Ｆｉｇｕｒｅ６㊀Ｇｌａｓｓｒｏｔａｍｅｔｅｒ可以计算出流体的高度在０ １６ｍ左右，这个高度与血管中的压强基本一致，再计算出这个高度自由落体产生的速度为０ １８ｍ／ｓ，近似于血液流速㊂因此搭建的实验平台如图７㊂图７㊀实验装置平台Ｆｉｇｕｒｅ７㊀Ｅｘｐｅｒｉｍｅｎｔａｌｕｎｉｔｐｌａｔｆｏｒｍ３ ３ ２㊀实验操作门静脉的流速在０ ２ｍ／ｓ，实验保持流速不变，硅胶导管的内部直径是８ｍｍ，可以计算出流速应该达到３６ ２Ｌ／ｈ，符合转子流量计的量程㊂将导管的另一端连接转子流量计的入口，打开引流袋的开关，通过调整高度，观察转子流量计的读数，当调整到３６Ｌ／ｈ的时候将引流袋固定并关闭开关㊂㊃０２６㊃北京生物医学工程㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀第４１卷将装配好的血流阻断器环绕导管一圈并调整装置的导管进行完全包裹，由于设计的阻断器是放大的，因此在硅胶导管外侧绑定一个金属杆㊂打开引流袋的开关，让流体开始流动，同时用手挤压动力装置，前端气囊膨胀，导管中的流速逐渐减慢，记录每一次加压后流速的变化情况㊂不断调整引流袋的高度，对不同高度下流体的速度变化进行测试，并用稀释牛奶做一组对照实验㊂记录数据如表１和表２㊂表１㊀牛奶从不同高度流下的速度Ｔａｂｌｅ１㊀Ｔｈｅｓｐｅｅｄｏｆｍｉｌｋｗｈｉｃｈｆｌｏｗｓｄｏｗｎｆｒｏｍｄｉｆｆｅｒｅｎｔｈｅｉｇｈｔｓ参数高度／ｍ０ ４０ ５０ ６０ ７流量／（Ｌ／ｈ）３６３９５２６１流速／（ｍ／ｓ）０ １９９０ ２１６０ ２８８０ ３３７表２㊀稀释后的牛奶从不同高度流下的速度Ｔａｂｌｅ２㊀Ｔｈｅｓｐｅｅｄｏｆｄｉｌｕｔｅｄｍｉｌｋｗｈｉｃｈｆｌｏｗｓｄｏｗｎｆｒｏｍｄｉｆｆｅｒｅｎｔｈｅｉｇｈｔｓ参数高度／ｍ０ ４０ ５０ ６０ ７流量／（Ｌ／ｈ）３６４２５１６０流速／（ｍ／ｓ）０ １９９０ ２３２０ ２８２０ ３３２３ ４㊀实验结果与分析对记录的数据进行处理，分析在不同高度下，牛奶在血流阻断器的作用下速度的变化趋势，如图８㊂引流袋高度不同，初始速度也就不一样，经过阻断器的阻断，流体流速在０ ８ｓ有着显著的降低，流量计的读数基本都维持在８Ｌ／ｈ以下，而这个数据相较于初始流量减少了８５％以上，模拟的导管流速得到了有效的控制㊂这就证明了在血液流速较高的情况下，阻断器也能够对血管有着明显的阻断效果，并最终维持在一个稳定的低速条件，给手术创造一个平稳的环境㊂现阶段还只能依靠医生的操作经验去控制肝门的阻断，没有定量的控制㊂研究表明，男性和女性在血液的密度上有一定的差异性，不同时间段的血液密度也有着明显的不同㊂在血液密度较大的时候，黏度也会相对增大，而密度较小的时候黏度也会减小㊂这会影响实际阻断的流速，但对阻断效果没有较大的影响，因此阻断器依旧能够有效阻断血流，达到一个安全的手术条件㊂４㊀讨论与结论本文针对腹腔镜手术中存在的出血问题，分析了在手术过程中常用的一些止血手段以及其中的利弊，设计了一款利用气囊进行阻断血流的阻断装置㊂利用气囊阻断不仅可以实时控制流体的多少，达到控制血流速度的效果，还可以减小阻断装置对人体的损伤，在血流阻断方向有着很好的研究价值㊂然后对装置的零件之间的连接关系进行了详细的叙述㊂通过３个基本方程的推导计算和ＡＮＳＹＳ软件的分析，得出了当速度为８ｍ／ｓ时，流体整体运动趋势最接近，有利于气体对气囊的填充，满足装置的速度要求㊂通过利用方程推导计算得出了动力装置的输出压强，为了方便操纵者的后续操作，进行了阻断压强的计算㊂为了验证设计结构的合理性和实用性，完成装置的设计后，通过３Ｄ打印技术，打印出实物，进行了体外模拟实验，并且对数据进行了一系列的分析㊂血流阻断装置的阻断效果在实验中起到了比较明显的效果，大大降低了流体的流动速度㊂并且速度的变化时间比较短，能够在较短时间内达到阻断效果㊂通过控制阀的调整，血流的速度能够有效地变化，实时控制血液流速㊂但是在模拟实验的过程中，所使用的模拟装置在结构上还是与人体有着一定的差距，使用气体能够控制血液的流速，但无法完全阻断血液的流动，比如卢榜裕等［７］通过临床手术，探讨腹腔镜下肝门阻断器在肝叶切除手术中的应用，设计了阻断组２３例，未阻断组１２例，手术中，阻断组的平均出血量为１００ ８００ｍＬ，未阻断组的平均出血量为２００ ２５００ｍＬ，可看出肝门血流阻断器可以明显减少术中出血，并且阻断组的手术成功率为１００％，无渗血及漏胆等现象，未阻断组在手术中出血量较多，并且有２例中途渗血㊁漏胆，术后２ｄ内再次开腹手术㊂因此，可以看出肝门血流阻断器在减少术中出血发挥着重大作用，极大地提高了手术的成功率和手术效率㊂但是想要完全阻断血流还需要对结构进一步改进㊂本设计相比于传统的腹腔镜手术在减少血流量方面上，在方法上有了很大的改进，开腹手术一般使用橡胶软管对第一肝门进行结扎，这样对人体的伤㊃１２６㊃第６期㊀㊀㊀㊀㊀㊀石更强，等：第一肝门血流阻断器的结构设计与性能研究图８㊀牛奶不同高度流下被阻断的流速变化Ｆｉｇｕｒｅ８㊀Ａｃｈａｎｇｅｉｎｔｈｅｆｌｏｗｒａｔｅｏｆｍｉｌｋｂｌｏｃｋｅｄｆｒｏｍｄｉｆｆｅｒｅｎｔｈｅｉｇｈｔｓ害较大，而且手术的难度也较大㊂一些研究人员将阻断带导入到人体内进行阻断，但此过程操作复杂，前期准备时间久，无法实时操控㊂在卢榜裕等［７］设计的肝门血流阻断器，采用铁丝对血管进行结扎，这样会极大伤害患者的血管，且不利于患者术后的血管恢复与流通㊂而本设计的创新之处在于将流体的压强应用到血流阻断中，采用穿刺技术将气囊导入到体内，通过压力的膨胀使得受迫部位的空间收缩，达到阻断的目的，不仅可以实时控制流体的多少，而且减少了对血管的损伤㊂为了阻断血流不能一次次加压，并且多次加压可能导致血管损坏，因此本文计算出了阻断血流的压力，方便进行操作㊂通过体外控制体内，操作简便，对人体和血管的伤害较小，达到了在方法上的改进，并且操作装置的任何一个模块都可以根据科技的发展而进行改进，对血流阻断方向有着很好的研究价值㊂本设计在腹腔镜手术止血技术创新上是一个突破，但是由于实验仪器的缺乏，要想设计出体积更小更加合理的血流阻断装置，还需要我国医疗器械的进一步发展㊂参考文献［１］㊀吴孟超，张智坚．肝切除手术的并发症及防治［Ｊ］．中华外科杂志，２００２，４０（５）：３３２－３３５．ＷｕＭＣ，ＺｈａｎｇＺＪ．Ｐｒｅｖｅｎｔｉｏｎａｎｄｔｒｅａｔｍｅｎｔｏｆｃｏｍｐｌｉｃａｔｉｏｎｓａｆｔｅｒｈｅｐａｔｅｃｔｏｍｙ［Ｊ］．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＳｕｒｇｅｒｙ，２００２，４０（５）：３３２－３３５．［２］㊀杨科，杨启．精准肝切除在肝癌手术中的应用［Ｊ］．世界华人消化杂志，２０１４，２２（２６）：３９９０－３９９３．ＹａｎｇＫ，ＹａｎｇＱ．Ｐｒｅｃｉｓｅｌｉｖｅｒｒｅｓｅｃｔｉｏｎｉｎｌｉｖｅｒｃａｎｃｅｒ［Ｊ］．ＷｏｒｌｄＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＤｉｇｅｓｔｏｌｏｇｙ，２０１４，２２（２６）：３９９０－３９９３．［３］㊀袁玉峰．腹腔镜肝切除 离断肝实质器械的选择和肝断面的处理［Ｃ］／／第六届微创外科论坛论文集．武汉：中华医学会，２０１４：３９－４０．［４］㊀中华医学会外科学分会肝脏外科学组．肝脏解剖和肝切除手术命名以及肝血流阻断方法与选择原则［Ｊ］．中华外科杂志，２０１０，４８（３）：１９６－２００．［５］㊀ＹａｎｇＨＹ，ＰａｎＭ．Ｅｎｇｉｎｅｅｒｉｎｇｒｅｓｅａｒｃｈｉｎｆｌｕｉｄｐｏｗｅｒ：ａｒｅｖｉｅｗ［Ｊ］．ＪｏｕｒｎａｌｏｆＺｈｅｊｉａｎｇＵｎｉｖｅｒｓｉｔｙ⁃ＳｃｉｅｎｃｅＡ，２０１５，１６（６）：４２７－４４２．［６］㊀ＲｏｓｓｉＵＧ，ＲｏｌｌａｎｄｉＧＡ，ＣａｒｉａｔｉＭ．Ｔｈｅｐｏｒｔａｌ，ｓｐｌｅｎｉｃ，ａｎｄｍｅｓｅｎｔｅｒｉｃｖｅｉｎｓｙｓｔｅｍ［Ｊ］．ＲｅｖｉｓｔａｄｅＧａｓｔｒｏｅｎｔｅｒｏｌｏｇíａｄｅＭéｘｉｃｏ（ＥｎｇｌｉｓｈＥｄｉｔｉｏｎ），２０２０，８５（２）：２０９－２１０．［７］㊀卢榜裕，陆文奇，蔡小勇，等．腔镜下第一肝门血流阻断器在部分肝切术中的应用［Ｊ］．生物医学工程与临床，２００５，９（２）：８４－８６，９７．ＬｕＢＹ，ＬｕＷＱ，ＣａｉＸＹ，ｅｔａｌ．Ａｐｐｌｉｃａｔｉｏｎｏｆｐｏｒｔａｌｂｌｏｏｄｏｃｃｌｕｓｉｏｎｄｅｖｉｃｅｉｎｌａｐａｒｏｓｃｏｐｉｃｈｅｐａｔｅｃｔｏｍｙ［Ｊ］．ＢｉｏｍｅｄｉｃａｌＥｎｇｉｎｅｅｒｉｎｇＣｌｉｎｉｃａｌＭｅｄｉｃｉｎｅ，２００５，９（２）：８４－８６，９７．（２０２０－０７－１４收稿，２０２１－０１－２７修回）㊃２２６㊃北京生物医学工程㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀第４１卷。
舒适淋浴花洒流量均匀性的实验研究
183舒适淋浴花洒流量均匀性的实验研究林泽峰 陆海涛 陈希敏（厦门英仕卫浴有限公司）摘 要：当下国内外均制定了一系列与水效相关的强制执行标准，并且在近几年的推广应用中取得了初步成效。
针对节水型产品流量的研究，主要定义其节水评价值和流量均匀性。
根据淋浴花洒及其加装节水模块后的流量测试结果，提出针对淋浴器的相对流量均匀性。
然后依照相应的水效等级提出更为客观的流量均匀性分级评价结果，并定义不同限流等级节水模块的合理使用范围。
关键词：水效，节水评价值，流量均匀性，相对流量均匀性DOI编码：10.3969/j.issn.1674-5698.2020.12.032Experimental Research of Flow Uniformity for Comfortable ShowersLIN Ze-feng LU Hai-tao CHEN Xi-min（Xiamen Easo Co.，Ltd.，）Abstract: A series of mandatory standards related to water efficiency are developed at home and abroad, achieving preliminary success with their popularization and application in recent years. The study on the flow of water-saving product mainly defines the minimum allowable values of water efficiency and uniformity of flow. According to the flow testing result for showers and showers with water-saving module, this paper puts forward the relative uniformity of flow for showers, suggests a more objective grading evaluation result for flow uniformity corresponding to water efficiency grades, and defines the appropriate range of application for water-saving module with different flow grades.Keywords: water efficiency, minimum allowable values of water efficiency, uniformity of flow, relative uniformity of flow作者简介： 林泽峰，硕士，工程师，从事流体力学相关研究。
垂直穿出水面圆柱体受到的非线性波浪载荷、波流载荷以及爬升与砰击现象试验研究
Experimental Investigations of Nonlinear Wave,Wave-current Loads,Runup and Slamming onVertical Surface-Piercing ColumnsLAN Jian 1,LIU Zhen 2(CC National Engineering Research Center of Dredging Technology and Equipment Co.,Ltd,Shanghai 200120,China;2.School of Naval Architecture,Ocean and Civil Engineering,ShanghaiJiao Tong University,Shanghai 200240,China)Abstract:Interactions between steep waves and two vertical surface-piercing cylinders are investigat⁃ed experimentally.The focus of this study is on nonlinear wave and wave-current forces,the scattering of steep waves,as well as wave kinematics around the circumference of cylinders,with an aim to inves⁃tigate the mechanisms of higher harmonic loads,runup and slamming due to steep waves.Two cylin⁃der diameters,6cm and 10cm,were adopted in the model set-up.PIV was utilized to measure kine⁃matics of flow field in this experiment.The specific objectives of this study are to (1)analyze the im⁃pact of wave steepness on wave forces on columns;(2)investigate current ’s effect on nonlinear wave loads by comparing the wave only and wave-current forces on the column;(3)observe the kinematics of steep wave,runup and slamming.Key words:steep wave;wave and wave-current forces;higher-harmonic forces;PIV;runup and slammingCLC number:P752Document code :Adoi:10.3969/j.issn.1007-7294.2020.12.0070IntroductionCylinder shape structure is a kind of widely used modality of offshore structures,such as the tension leg platform (TLP),gravity based structures (GBS),spar platform and offshore wind turbine foundations.Efficient estimation of the forces on these offshore structures in waves is very important for preliminary design.Linear theory to calculate wave loads has been comparatively mature to date,whereas methods to estimate higher-order nonlinear wave loads accurately have not been well developed.Higher-order wave forces have very significant effects on TLP and GBS because of their own high natural resonance frequency.Also structure fatigue is sensitive to high frequency ringing which is a kind of vibration at the resonant frequency of a structure and concerned with regard to ex⁃treme loading [1].However the generation mechanism of these nonlinear high-frequency wave loads is not fully understood.Estimation of wave forces on a vertical surface-piercing cylinder has been a research subject for over 60years.Havelock [2]first provided the linear diffraction solution in infinite water depth and第24卷第12期船舶力学Vol.24No.122020年12月Journal of Ship Mechanics Dec.2020Article ID ：1007-7294（2020）12-1595-14Received date ：2020-06-29Biography ：LAN Jian(1990-),male,engineer,E-mail:********************;LIU Zhen(1985-),male,Ph.D.student.1596船舶力学第24卷第12期MacCamy and Fuchs[3]provided a linear solution for intermediate water depth.Since then,this topic has provoked much research activity contributing to the formulation of many new theories(Faltinsen et al[4];Malenica&Molin[5];Rainey[6-7]),forces models and experimental studies(Sheikh and Swan[8]; Swan et al[9];Boo S Y[10];Masterton and Swan[11];Masterton et al[12];Li et al[13-14]).The most traditional methods to calculate the wave loads on a fixed cylinder is linear diffraction theory for large dimen⁃sion structures and Morison’s equation[15]for small ones.Although linear wave loads on offshore structures calculated by some linear theories have been widely identified and used in engineering, some phenomena for large platforms experiencing transient structural deflections at natural frequen⁃cies substantially higher than the dominant wave frequencies known as‘ringing’cannot be ex⁃plained well by traditional theories.Actually,it is nonlinear wave loads that lead to structure high frequency vibration.Faltinsen et al[4]and Malenica and Molin[5]constructed two third order diffrac⁃tion theories to estimate these nonlinear wave loads based on different methods,asymptotic expan⁃sion and perturbation expansion respectively.Many experimental studies(Swan et al[9];Masterton and Swan[11];Masterton et al[12];Roos et al[16-17])reveal that linear wave loads commonly underestimate total loads in steep waves.In addi⁃tion,it is found that there exist some higher harmonic forces which are comparative to the second or⁃der wave forces on a fixed cylinder in comparatively steep waves.To derive the total wave forces on offshore structures as far as possible,researchers have paid more attention to necessarily higher-harmonic forces.For example,Chaplin[18]and Grue and Huseby[19]analyzed ringing of a vertical cyl⁃inder in waves and revealed relationship between higher harmonic wave loading and the secondary loading cycle(SLC)that occurs after the force crest passes the cylinder’s axis.In the present paper, it mainly focuses on the nonlinear components in the interaction between steep waves and a fixed surface-piercing cylinder,on the interactions between nonlinear steep waves and fixed surface-piercing column structures and some nonlinear phenomena such as runup and slamming.This pa⁃per is organized as follows.A brief overview of experimental set-up is described in Chap.1,results and discussions are given in Chap.2,and concluding remarks are shown in Chap.3.1Experimental set-up1.1Wave flumeThe physical measurements were conducted in the2-D wave flume at Education Ministry Key Laboratory of Hydrodynamics,Shanghai Jiao Tong University,P.R.China.The flume is60m long, 1.2m deep and0.8m wide.The experiments were conducted at a still-water depth of0.6m.The flume was equipped with a hydraulically driven piston-type wave-making system and the wave en⁃ergy absorber is mounted at the end of the flume.Currents could be generated at the same time and the maximum velocity reached20cm/s.Six resistance-wire wave probes were mounted to measure the wave elevation and phase.A Nortek acoustic Doppler velocimeter(ADV,velocity range1m/s, sampling rate200Hz)with a specified accuracy of1mm/s was used to measure water particle ve⁃locity in currents.1.2Wave and current conditionsWaves considered in the experiment were all regular waves with different wave steepness rang⁃ing from 0.07to 0.33.There were two unidirectional currents in wave-current conditions which were following and opposing compared to wave propagating direction.In the experiments,wave-on⁃ly and wave-current conditions were considered respectively.The details of the waves are shown in Tab.1.And the wave flume set-up is shown in Fig.1.Tab.1Wave conditionsCase A1A2A3A4A5A6A7T (s)1.01.00.90.90.90.90.9H (m)0.0320.0550.0620.0890.1060.1230.131kA0.070.110.160.220.260.310.33KC (D =6cm)1.6752.8783.2454.6585.5476.4376.856KC (D =10cm)1.0051.7271.9532.7953.3283.8624.113(In Tab.1,H is wave height;kA is wave steepness;KC is Keulegan-Carpenter number.)Fig.1Wave flume set-up1.3Model set-upIn this experimental study,two kinds of diameter of the cylinder were adopted (D =6cm and 10cm).Corresponding Keulegan-Carpenter number KC was below 7,so the wave forces on the col⁃umns were inertial or potential force dominant.The column structures were top mounted extending 0.4m above the still water line.The wave forces on the fixed structures were recorded through a six-component force transducer mounted at the top of column.Here we mainly paid attention to forces on the structures in wave propagating direction.All the structures were mounted 25m down⁃stream from the wave maker.The corresponding experimental test cases are listed in Tab.1.1.4PIVPIV was utilized in the experiments to capture the kinematics of flow field in front of columns in the waves.The PIV system is composed of a pulsing laser,a high-speed camera and a PC to re⁃cord data.The arrangement of the devices is shown in Fig.2.The laser was placed on the top of the wave flume and the laser sheet was reflected to the test section by a mirror.During the process of ex⁃periment,the field of view was lighted by the reflected light into the water in the flume.The high-第12期LAN Jian et al:Experimental Investigations of Nonlinear Wave, (1597)(a)(b)speed camera on the side of the flume was used to cap⁃ture the vertical laser plane.The solution of the camera was 1024×1280pixels and the frame rate was 500Hz.It meant that the time between two images was just 2ms.2Results and discussion2.1Wave loads on structuresBefore measurement of the wave forces on the struc⁃tures,the wave surface elevation without structures in the flume was recorded by wave gauges.Wave elevations in seven wave cases are shown in Fig.3.Fig.3Stable stage of incident waves recorded by wave gaugesFig.2PIV devices arrangement1598船舶力学第24卷第12期The wave forces on the cylinders,one of which was 6cm in diameter and the other was 10cm,were measured in these regular waves.The history of wave forces on the cylinder (D =6cm)are shown inFig.4.Fig.4History of wave forces on the cylinder (D =6cm)From the figure above,we find that wave forces are approximately regular for wave cases of A1to A6,but as to Case A7,the second loading cycle [19]appears in the wave force history.The reason of this phenomenon is relevant to the strong nonlinearity of incident waves,resulting in significant nonlinear interactions with the structure.According to the results of wave forces,we evaluated them by Fourier analysis to get different harmonic components of the total forces exerted on the cylinder.The Fourier transformation results of wave forces on the cylinder (D =6cm)in wave cases of A1-A3and A7are presented below in Fig.5.From Fig.5,it can be seen that for Case A1the wave force has no significant higher harmonics,indicating that linear wave theory is efficient to estimate the wave loads for waves with small steep⁃ness.However,as wave height increases,the higher harmonic components start to arise in Case A2and Case A3.For Case A7,in which the wave steepness reaches 0.33and KC number is 6.856,the second and third harmonics are of the same magnitude corresponding to nearly 13%of the amount of linear component.Tab.2presents the amplitudes of each harmonics on the structure.Also com⁃parison was made between diffraction theory and experimental results as shown in Fig.6.The differ⁃ences between the values evaluated by diffraction theory and measured first harmonic loading are nearly the same when wave steepness is small.However,measured values start to go beyond theoret⁃第12期LAN Jian et al:Experimental Investigations of Nonlinear Wave, (1599)ical results for large wave steepnessconditions.Fig.5Amplitude spectrum of wave forces on the cylinder (D =6cm)that as the wave steepness of the incident waves increases,there are clear differences on the water surface around the cylinder in the flume.There are evident scattering waves when steep waves pass the cylinder.Fig.7shows water surface near the cylinder in steep waves.Nonlinearity is induced partly by the disturbance from free surface,and this kind of wave (incident and scat⁃tered waves)-structure interaction will cause nonlinear loads.The forceresults of interactions between the same incident waves with a larger cylinder (D =10cm)are shown in Fig.8.Evident secondary loading cycle does not occur in all the cases.First four components of harmonic wave loading amplitudes are presented in Tab.3.For Case A7,it is clear to see that the wave forces become low suddenly,because the wave has been broken when it gets to the structure.For this cylinder,the wave loads correspondingly increase,whereasTab.2The first four harmonic amplitudesof wave forcesFig.6Linear theoretical results (solid line)and mea⁃sured amplitude of the first components of wave forces on the cylinder (D =6cm,solid circle)Fig.7Water surface influenced by inci⁃dent wave-scattering wave-column interaction in steep waves F 1/ρg A a 21600船舶力学第24卷第12期Fig.8Wave forces on the cylinder (D =10cm)the higher harmonic components are not com⁃paratively more significant than those exerted by the cylinder of 6cm in diameter.At the same time,the evident secondary loading cy⁃cle does not occur but the second and third or⁃der nonlinear wave loads are large in some cases,especially Cases A5and A6.So it is concluded that scattering parameter kA is animportant factor relevant to SLC ’s occurrence.2.2Wave-current loads on columns In this section,we discuss the wave-currentloads on the column structures.Firstly the following or opposing current was generated and then when it turned steady,the waves began to be generated and propagated.Fig.1shows the working principle to make wave and current of the wave flume.Currents were generated by the recycle pump.Atthe first step,we used ADV to measure the velocityprofile of the current.The velocity distribution of fol⁃lowing and opposing currents is shown in Fig.9.WhenTab.3The first four harmonic amplitudesFig.9The velocity distribution of followingand opposing current第12期LAN Jian et al:Experimental Investigations of Nonlinear Wave, (1601)current became steady,waves were generated by the wavemaker on the left end.And then wave sur⁃face were recorded by using wave gauge.From the results,it is found that the wave height decreases when following current interacts with waves.On the contrary,wave height increases in wave-oppos⁃ing current coexisting conditions.But the wave period does not change.The wave height changesare presented below in Tab.4and Fig.10.Tab.4Wave-current conditions from experimental measurementCase B1B2B3B4B5B6B7Wave period(s)1.01.00.90.90.90.90.9Wave height(m)Following current0.0270.0490.0600.0760.0900.0980.100Opposing current0．0370．0700．0730．0930．1080．1100．106Without current0.0320.0550.0620.0890.1060.1230.131Fig.10Change of wave height with wave steepness increasingAs we can see from above,current has increasingly evident influence on wave height or wavesteepness as wave height becomes higher and higher.As to opposing current conditions,when wave steepness is beyond 0.26,wave height begins to decrease because opposing current leads to local wave breaking for steeper waves.So it denotes that steep waves are more sensitive to current.Here we analyze wave-current loading history record of a typical case.In Fig.11,wave-follow⁃ing current,wave-opposing current and wave-only loads are depicted respectively.Wave-opposing current force turns out about 20%-30%larger than wave-only force,while wave-following current loads correspondingly become 10%-20%lower than wave-only loads.The first order wave-oppos⁃ing current loading on the column is 11.4%larger than wave-only loading.As to second and thirdharmonics,the amplitudes of wave-only force and wave-opposing current force are significantly higher than wave-following force.The reason of the phenomenon is current ’s effect on fluid parti⁃cle movement,which results in different procedures in the interaction between waves and the struc⁃tures.Following current-wave Opposing current-wave Without current1602船舶力学第24卷第12期Fig.11Wave-only and wave-current loading on the single cylinder (D =6cm,Case B2)and corresponding Fourier analysis results2.3PIV resultsFor waves with and without a column in place,the kinematics of water particle are measured by using PIV.Fig.12shows the velocity profile under the wave crest in different wave cases.Fig.12Horizontal velocity distribution under wave crest.(Theory):Wave particle velocity from linearwave theory;(PIV):Wave particle velocity under wave crest without column in wave;(PIV-D =6cm):Wave particle velocity under wave crest,32.74mm in front of cylinder;(PIV-D =10cm):wave particle velocity under wave crest,30.39mm in front of cylinderFrequency/HzM a g n i t u d e /NWave-following current loads Wave-opposing current loads Wave loadsWave-following current Wave-opposing current Wave onlyt (s)F (N )Z (m )第12期LAN Jian et al:Experimental Investigations of Nonlinear Wave,…1603From the pictures above,it seems that horizontal components under the wave crest decay slightly faster than linear theory.On one hand,the particle velocities decrease evidently with col⁃umn in place compared to velocity profile without cylinder in place or linear theory result.I t is also simultaneously revealed that waves scattering is more significant for larger column as expected be⁃cause the decreasing wave energy of incident waves will give rise to scattering waves.Near the still water surface,velocities turn to be increasingly irregular above the still water line because of distur⁃bance from wave-wave or wave-body interaction and resulting local breaking at wave surface espe⁃cially for steep waves.This is an important factor which induces the nonlinear wave loading on the columns.2.3.1Secondary waveAlthough the scale of the cylinder under consideration is comparatively small,clear observa⁃tions identify unexpected scattering mode,secondary waves.Secondary waves which are induced by periodic wave scattering are proposed to explain the wave-wave interaction which leads to local nonlinear phenomenon,runup,slamming and SLC.When steep wave crest comes to the cylinder,significant runup and wash-down occur on the front face of cylinder.From Fig.13,it is clear that a disturbance from wash-down fluid generates a pile of water at the front corner of cylinder beyond the wave surface obviously.This periodic disturbance will propagate outside from the initial wave surface.It can also be seen that a distinct secondary wave crest of scattering waves is generated up⁃stream from Fig.13.The wave elevation influenced by secondary waves is well in accordance with the secondary wave loading in forcehistory.Fig.13Wave runup(left)and wash-down(right)2.3.2Runup and slammingIn steep wave conditions,runup and slamming on the column are observed.A typical slamming phe⁃nomenon is captured from observation in steep waves as seen from Fig.14.Fig.15shows the process in which runup and slamming are generated.From the high-speed camera images and experimental video record,wave runup and slamming on the column have the same generation mechanism that interaction be⁃tween incident wave crests and secondary waves in the front face of column leads to cumulated waterFig.14Slamming on the column insteep waves1604船舶力学第24卷第12期washing up to the front face of the column,because horizontal velocity of water particle under wave crest is maximum.Fig.15(a)-(i)show a cycle of propagation of secondary waves and runup and Fig.15(a)-(f)and(j)-(l)show the process of slamming generation.Fig.15(a)presents large distur⁃bance induced by wash-down at the corner of the cylinder.Fig.15(b)-(e)show secondary scattering wave propagating upstream with an evident wave crest.When wave crest of incident wave encoun⁃ters the secondary waves at the front of cylinder(from Fig.15(e)),interaction between them causes a pile of water washing up to the front face of the cylinder to generate runup because of block of the structure(from Fig.15(i)).Like this procedure,slamming is caused in the same way,just because of larger distance from wave-wave interaction point from the column and larger horizontal velocity of incident steep wave crest and resulting wave breaking on the column.Slamming is shown in Fig.15 (j)-(l).(a)(b)(c)(d)(e)(f)(g)(h)(i)(j)(k)(l)Fig.15A cycle of runup and slamming generation in steep regular waves3Concluding remarksWe have investigated experimental measurements of wave,wave-current forces and especially nonlinear higher harmonic components on column structures.Second and third harmonics are main⁃ly analyzed.Wave steepness plays an important role in development of nonlinear wave force.Very steep waves will lead to significant second and third harmonic nonlinear forces which are in the same order.When wave and current coexist,opposing current increases the nonlinearity of incident wave and corresponding forces on the structures,which also leads to earlier occurrence of secondary load⁃ing cycle in respectively small waves.On the country,following current reduces the wave steepness. From PIV results,the velocity distribution of steep waves interacting with column structure al⁃so confirms the disturbance at the flow field near the water surface,which is an important factor of generation of nonlinear wave force components.High speed camera images capturing the kinematics of waves reveal that runup and slamming on the front of cylinder are induced by interaction between incident wave crest and secondary wave crest at the front face of cylinder.This provides a physical mechanism for understanding of runup and slamming and suggests that new model can be applied to simulate runup and slamming accord⁃ing to incident wave-small opposing propagating wave interaction at the structure.AcknowledgementsThe technical assistance in the hydrodynamic laboratory by Prof.Fang is gratefully acknowl⁃edged.References[1]Ma Y X,Dong G H,et al.High-harmonic focused-wave forces on a vertical cylinder[J].Ocean Engineering,2009,35(8): 595-604.[2]Havelock T H.The pressure of water waves upon a fixed obstacle[J].Proceedings of the Royal Society of London.Series A. Mathematical and Physical Sciences,1940,175(963):409-421.[3]MacCamy R C,Fuchs R A.Wave forces on piles:A diffraction theory[R].No.TM-69.Corps of Engineers Washington DC Beach Erosion Board,1954.[4]Faltinsen O M,Newman J N,Vinje T..Nonlinear wave loads on a slender vertical cylinder[J].Journal of Fluid Mechan⁃ics,1995,289:179-198.[5]Malenica,Šime,Molin B.Third-harmonic wave diffraction by a vertical cylinder[J].Journal of Fluid Mechanics,1995,302: 203-229.[6]Rainey R C T.Slender-body expressions for the wave load on offshore structures[J].Proceedings of the Royal Society of Lon⁃don.Series A:Mathematical and Physical Sciences,1995,450(1939):391-416.[7]Rainey R C T.The hydrodynamic load at the intersection of a cylinder with the water surface[C].Proceedings of10th Interna⁃tional Workshop on Water Waves and Floating Bodies,1995.[8]Rizwan Sheikh,Chris Swan.The interaction between steep waves and a vertical,surface-piercing column[C]//ASME2003 22nd International Conference on Offshore Mechanics and Arctic Engineering.American Society of Mechanical Engineers, 2003.[9]Swan Chris,et al.Wave forcing and wave scattering from a vertical surface-piercing cylinder[C].ASME200524th Interna⁃tional Conference on Offshore Mechanics and Arctic Engineering,2005.[10]Boo S Y.Measurements of higher harmonic wave forces on a vertical truncated circular cylinder[J].Ocean Engineer⁃ing,2006,33(2):219-233.[11]Stephen Masterton,Chris Swan.Wave forces on a single surface-piercing column:Comparisons between theory and experi⁃ment[C]//25th International Conference on Offshore Mechanics and Arctic Engineering.American Society of Mechanical Engineers,2006.[12]Stephen Masterton,Chris Swan,van Zutphen H.Nonlinear wave scattering from a single surface-piercing column compari⁃son with second-order theory[C]//ASME200726th International Conference on Offshore Mechanics and Arctic Engineer⁃ing.American Society of Mechanical Engineers,2007.[13]Li Jinxuan,Wang Zhanhang,Liu Shuxue.Experimental study of interactions between multi-directional focused wave and vertical circular cylinder,Part I:Wave run-up[J].Coastal Engineering,2012,64:151-160.[14]Li Jinxuan,Wang Zhanhang,Liu Shuxue.Experimental study of interactions between multi-directional focused wave and vertical circular cylinder,Part II:Wave force[J].Coastal Engineering,2014,83:233-242.[15]Morison J R,Johnson J W,Schaaf S A.The force exerted by surface waves on piles[J].Journal of Petroleum Technolo⁃gy,1950,2(5):149-154.[16]Jannicke Roos,Chris Swan,Sverre Haver.Wave impacts on the column of a gravity based structure[C]//ASME201029th International Conference on Ocean,Offshore and Arctic Engineering.American Society of Mechanical Engineers,2010.[17]Roos J S,et al.An experimental investigation of wave impacts on the deck of a gravity based structure[C]//Proceedings of the28th International Conference on Ocean,Offshore and Arctic Engineering.Hawaii,USA,2009.[18]Chaplin J R,Rainey R C T,Yemm R W.Ringing of a vertical cylinder in waves[J].Journal of Fluid Mechanics,1997,350: 119-147.[19]John Grue,Huseby M.Higher-harmonic wave forces and ringing of vertical cylinders[J].Applied Ocean Research,2002,24 (4):203-214.垂直穿出水面圆柱体受到的非线性波浪载荷、波流载荷以及爬升与砰击现象试验研究兰剑1，刘震2（1.中交疏浚技术装备国家工程研究中心有限公司，上海200120；2.上海交通大学船舶海洋与建筑工程学院，上海200240）摘要：本文对陡波中两个垂直圆柱体与波浪之间的干涉现象做了研究。
Fluid-Structure Interaction
Fluid-Structure Interaction Fluid-Structure Interaction (FSI) is a complex and interdisciplinary fieldthat involves the interaction between a fluid flow and a solid structure. This interaction can have significant effects on the behavior and performance of both the fluid and the structure, making it a crucial consideration in various engineering applications. The study of FSI is essential in understanding phenomena such as flutter in aircraft wings, vortex-induced vibrations in offshore structures, and blood flow in arteries. One of the key challenges in FSI is accurately modeling and simulating the interaction between the fluid and the structure. This requires a deep understanding of both fluid dynamics andstructural mechanics, as well as sophisticated computational tools to solve the coupled equations governing the FSI problem. The development of numerical methods for FSI simulations has been a major focus of research in recent years, with the goal of improving the accuracy and efficiency of FSI models. In addition to numerical simulations, experimental techniques play a crucial role in studying FSI phenomena. Physical testing allows researchers to validate and calibrate their numerical models, as well as to investigate complex FSI behaviors that aredifficult to capture through simulations alone. Experimental facilities such as wind tunnels, water tanks, and biomedical labs provide valuable data for understanding the dynamics of FSI and for developing new design guidelines for engineering structures. The study of FSI has wide-ranging applications across various industries, including aerospace, civil engineering, biomechanics, and marine engineering. In aerospace, FSI is essential for predicting the aerodynamic performance and structural integrity of aircraft components, such as wings and fuselage. In civil engineering, FSI is used to analyze the behavior of buildings and bridges under wind and earthquake loads, as well as to optimize the design of offshore structures for oil and gas production. From a biomedical perspective, FSI is critical for understanding the flow of blood in arteries and theinteraction between blood vessels and surrounding tissues. This knowledge is essential for diagnosing and treating cardiovascular diseases, as well as for designing medical devices such as stents and artificial heart valves. In marine engineering, FSI is used to study the response of ships and offshore platforms towaves and currents, as well as to optimize the design of marine structures for improved performance and safety. Overall, the study of Fluid-StructureInteraction is a fascinating and challenging field that requires amultidisciplinary approach to address complex engineering problems. By combining theoretical analysis, numerical simulations, and experimental testing, researchers can gain valuable insights into the behavior of fluid-structure systems and develop innovative solutions for a wide range of practical applications. The continued advancement of FSI research will lead to new discoveries and technologies that will shape the future of engineering and science.。
管内油气两相流动空泡份额的检测及其波动特性的研究
上海交通大学博士学位论文管内油气两相流动空泡份额的检测及其波动特性的研究姓名：***申请学位级别：博士专业：工程热物理指导教师：***20040901摘要管内油气两相流动空泡份额的检测及其波动特性的研究摘要海洋石油工业在我国能源工业中具有重要的地位和作用其关键技术由多相管流特性空泡份额是研究这三大关键技术的重要参数之一多相流动过程中流动压降流动不稳定的产生以及空泡波的滋生等都与空泡份额密切相关研制了一种新型的电容传感器和数据采集系统在线测量 1½¨Á¢Á˶༫°åµçÈÝ´«¸ÐÆ÷µÄÈýάÓÐÏÞÔª·ÂÕæÄ£ÐͱȽÏÁËÎÞÖáÏòÆÁ±Îµç¼«Ñо¿·ÖÎöÁËÖáÏòÆÁ±Îµç¼«³¤¶È¶ÔMETC型电容传感器轴向空间电势分布的影响激励电极尺寸相同的情况下满管静态电容值以及两种类型传感器的满管／空管电容变化量2¹Ü±Ú¶ÔÓÚÍâÖÃʽ´«¸ÐÆ÷¼«°å¼äµçÈÝÖµ±ä»¯µÄÏßÐÔ¶ÈÓÐ׎ϴóµÄÓ°Ïì·ÂÕæ½á¹û±íÃ÷»ùÓڱȽϷÖÎöºÍ·ÂÕæ¼ÆËã½á¹ûÓÃÓÚÓÍÆøÁ½ÏàÁ÷¶¯¹ý³Ì¿ÕÅݷݶî²ÎÊýµÄ¼ì²â²ÉÓÃMETCÐÍͬ²½Çý¶¯ÖáÏò±£»¤µç¼«Äܹ»Í¬上海交通大学博士学位论文 管内油气两相流动空泡份额的检测及其波动特性的研究时检测两组空泡份额信号 3ÔÚʵÑéÊÒÖÐÔËÓþÛÂÈÒÒÏ©°ô¾ÛÂÈÒÒÏ©¿ÅÁ£ºÍ±½ÒÒÏ©ÅÝÄ-¿ÅÁ£ÔÚ´«¸ÐÆ÷ÄÚÄ£ÄâÁ˲»Í¬µÄÁ÷Ðͽṹ²âÁ¿Á˲»Í¬Ä£ÄâÁ÷Ð͵ĿÕÅݷݶîÖµ±¾ÏµÍ³ÔÚ¾²Ì¬ÊµÑéÖеIJâÁ¿Îó²îСÓÚ6%在油气两相流试验环路上对本文所研制的空泡份额测量系统进行了实验标定空泡份额测量系统的精度大于95%(相对于满量程)5¶Ôˮƽ¹ÜºÍ5种倾角(1o3oʵÑé½á¹û±íÃ÷¹ÜµÀÇã½Ç¶ÔÓÍÆøÁ½ÏàÁ÷¶¯µÄÁ÷Ðͱ仯ÓÐ×ÅÖØÒªµÄÓ°ÏìÔÚ±¾ÎĵÄʵÑéÌõ¼þϲ¨×´²ãÁ÷ºÍ¶ÎÈûÁ÷ÈýÖÖÁ÷Ð͵¯×´Á÷ºÍ¶ÎÈûÁ÷ÈýÖÖÁ÷ÐÍˮƽ¹ÜÖжÎÈûÁ÷Éú³ÉµÄÁÙ½çÒºÏà±í¹ÛÁ÷ËÙΪ0.1132m/s (120m3/d)½ö¸Ä±äÆøÏàÁ÷Á¿ÎÞ·¨Éú³É¶ÎÈûÁ÷Á÷ÐÍÇãб¹ÜÖв¢¾ßÓÐÒ»¶¨µÄ¹æÂÉÐÔËæ×ÅÆøÏà±í¹ÛÁ÷ËÙµÄÔö¼ÓÔÚÏàͬµÄÆøÏà±í¹ÛÁ÷ËÙ϶ÎÈûÉú³ÉƵÂÊÔö¼Ó¶ÎÈûÉú³ÉƵÂÊÔö¼Ó分析了气液两相流动过程中空泡份额波的一维线性模型波速以及增长和衰减特性进行了研究在本文的实验条件下空泡份额波的频率不大于3Hzµ±ÆøÏà±í¹ÛÁ÷ËÙÒ»¶¨Ê±¿ÕÅݲ¨µÄ´«²¥摘要速度增大随着气相表观流速的增加液相表观流速下在一定的液相表观流速下二者的频率都逐渐降低空泡份额电容传感器空泡份额波上海交通大学博士学位论文 管内油气两相流动空泡份额的检测及其波动特性的研究STUDY ON THE W A VE CHARACTERISTICS ANDMEASUREMENT OF VOID FRACTION OF OIL-GASTWO-PHASE FLOW IN PIPESABSTRACTThe ocean oil industry plays an important role in Chinese energy industry. The oil-gas-water multiphase transportation technology is an effective method of the oil exploitation in the seabed. The key technologies include the multiphase pressurization, the multiphase flowmeter and the multiphase flow control. The void fraction is a major parameter of the multiphase flow. The variation of the void fraction has a serious effect on the flow pressure gradient, the flow regime transition, the void fraction wave and the flow instability. The real-time measurement of the void fraction is also very important for the safety and the quality assurance in the industry. Based on the electrical tomography technology (ECT), a new type of capacitance sensor and a data acquisition system has been developed in this research to measure the void fraction of the oil-gas multiphase transportation pipelines. The followings are the major contributions and results:(1) A three-dimensional finite element model for the multi-electrode capacitance sensor is developed. A simulation study of different structures of capacitance sensors has been carried out using ANSYS software. Voltage distributions in the central axial sections of three capacitance sensors (UMIST, METC and sensors without axial screen) are calculated and analyzed. The effect of axial screen length on the voltage distributions in the sensor’s section is studied. Based on the three-dimensional model, the capacitance values of a full-pipe, an empty-pipe and their varieties are calculated. The characteristics of two types of capacitance sensors with external electrodes and internal electrodes are analyzed and compared. The results of the simulation and the analysis are the important elements in the design of a new capacitance sensor.ABSTRACT(2) The permittivity of the pipe wall has a serious effect on the linearity of the capacitance variations between electrodes, especially on the neighbor electrodes. The simulation results show that the capacitance variation of full/empty pipe of neighbor electrodes is negative. Based on the results of simulation and analysis, a multi-electrodes capacitance sensor with a new structure is developed to measure the void fraction in the oil-gas two-phase flow. The sensor has twelve internal electrodes. The axial screens of the sensor are the synchronous “METC” electrodes. In addition, the sensor has two groups of measurement electrodes. Two groups of capacitance signals can be collected at the same time. The cross correlation function of the two groups of signals can be analyzed to determine the velocities of the void fraction waves.(3) The data collection system and the software of the measurement system are developed. In the laboratory, some flow regimes are simulated using PVC sticks, PVC pipes, PVC beads and styrene foam particles. The measurement system is calibrated by measuring the different simulation flow regimes. The measurement results indicate that the error of the void fraction measurement system is less than 6%.(4) The void fraction measurement system is tested on the oil-gas two-phase flow loop. The experimental results show that the measurement precision of the system is more than 95%. The void fraction measurement system can meet the precision demands of the oil industry.(5) The characteristics of the oil-gas two-phase flow in a horizontal pipe and five inclined pipes (1ｏ3ｏＴｈｅ ｏｂｌｉｑｕｉｔｉｅｓ ｏｆ ｔｈｅ ｉｎｃｌｉｎｅｄ ｐｉｐｅｓ ｈａｖｅ ａ ｓｅｒｉｏｕｓ ｅｆｆｅｃｔ ｏｎ ｔｈｅ ｆｌｏｗ ｒｅｇｉｍｅｓ． Ｔｈｅ ｆｌｏｗ ｒｅｇｉｍｅｓ ｏｆ ａ ｈｏｒｉｚｏｎｔａｌ ｐｉｐｅ ａｒｅ ｄｉｆｆｅｒｅｎｔ ｆｒｏｍ ｔｈｅ ｆｌｏｗ ｒｅｇｉｍｅｓ ｏｆ ａｎ ｉｎｃｌｉｎｅｄ ｐｉｐｅ． Ｕｎｄｅｒ ｔｈｅ ｅｘｐｅｒｉｍｅｎｔａｌ ｃｏｎｄｉｔｉｏｎｓ ｏｆ ｔｈｉｓ ｒｅｓｅａｒｃｈ， ｔｈｒｅｅ ｆｌｏｗ ｐａｔｔｅｒｎｓ ｏｆ ｔｈｅ ｓｔｒａｔｉｆｉｅｄ ｆｌｏｗ， ｔｈｅ ｗａｖｅ ｆｌｏｗ ａｎｄ ｔｈｅ ｐｌｕｇ ｆｌｏｗ ａｒｅ ｏｂｓｅｒｖｅｄ ｉｎ ｔｈｅ ｈｏｒｉｚｏｎｔａｌ ｐｉｐｅ． Ｔｈｒｅｅ ｆｌｏｗ ｐａｔｔｅｒｎｓ ｏｆ ｔｈｅ ｂｕｂｂｌｅ－ｓｔｒａｔｉｆｉｅｄ ｆｌｏｗ， ｔｈｅ ｓｌｕｇ ｆｌｏｗ ａｎｄ ｔｈｅ ｐｌｕｇ ｆｌｏｗ ａｒｅ ｓｈｏｗｎ ｉｎ ｔｈｅ ｉｎｃｌｉｎｅｄ ｐｉｐｅ． Ｉｎ ｔｈｅ ｉｎｃｌｉｎｅｄ ｐｉｐｅ， ｔｈｅ 上海交通大学博士学位论文 管内油气两相流动空泡份额的检测及其波动特性的研究boundary velocity of gas superficial velocity between slug flows and plug flows is 0.09433m/s (100m3/d). If the liquid superficial velocity is constant, the frequency of liquid plugs reduces as the gas superficial velocity is increased. If the gas superficial velocity is constant, the frequency of liquid plugs increases as the liquid superficial velocity increases. As the inclined obliquity is enlarged, the frequency of liquid plugs increases.(6) The one-dimensional linear model of gas and liquid two-phase flow is summarized and analyzed. The characteristics of void fraction waves in horizontal and inclined pipes are studied using spectrum and correlation analysis methods. The results are as followings:The different flow regimes have different velocities of void fraction waves. If the gas superficial velocity is constant, the velocity of void fraction waves increases as the liquid superficial velocity increases. If the liquid superficial velocity is constant, the velocity of void fraction waves increases as the gas superficial velocity increases.In the inclined pipe, the frequency of void fraction waves of plug flow is as same as the frequency of liquid plugs. If the liquid superficial velocity is constant, their frequencies reduce as the gas superficial velocity increases. If the gas superficial velocity is constant, their frequencies increase as the liquid superficial velocity increases.KEY WORDS上海交通大学学位论文原创性声明本人郑重声明是本人在导师的指导下除文中已经注明引用的内容外对本文的研究做出重要贡献的个人和集体本人完全意识到本声明的法律结果由本人承担日期上海交通大学学位论文版权使用授权书本学位论文作者完全了解学校有关保留同意学校保留并向国家有关部门或机构送交论文的复印件和电子版本人授权上海交通大学可以将本学位论文的全部或部分内容编入有关数据库进行检索缩印或扫描等复制手段保存和汇编本学位论文 本学位论文属于 不保密请在以上方框内打 学位论文作者签名 日期 年 月 日主要符号说明主要符号说明A 流道截面积 2m C 电容F k C 空泡份额波速 s m / X C 待测电容 F D 管径 mE 电场强度 )/(/C N m V f 频率 Hz g 图像灰度 J 容积流速 s m / L 电极长度 m Q 感应电荷量 C R 电阻 Ω ii R 自相关函数 ij R 互相关函数 f R 反馈电阻ΩS 传感器空间单元的敏感度 u 速度 s m / C V 激励电压 V SG V 气相表观流速 s m / SL V 液相表观流速 s m / α空泡份额α 时均空泡份额 ϕ 电位V0ε 真空中介电常数 m F /1085.812−× ε 相对介电常数 θ 电极张角 rad λ 归一化电容值 ρ 密度 3/m kg δ 灰度滤波因子 ψ 空泡份额波的增长率 0τ 渡越时间s Γ 连续性方程中的源项 s kg /上下标 L 液相gas空气/氮气第一章 绪论１．１ 课题研究背景 随着全球石油需求量的持续增加以及陆上石油储量的日益减少海洋石油工业在世界范围内得到了快速的发展 中国海上油气资源勘探主要集中于渤海东海及南海北部大陆架天然气资源量为10.6万亿立方米近年来滩海等地域转移，已经陆续发现了许多大型的油气资源专家预测我国原油产量中的增量部分主要来自海上石油［１］ 油气水多相混输技术是指在同一条管线内同时输送油井所产出的石油它是海底石油开采输送的一种有效手段减少运行费用采用混输技术可以降低油气田开采费用的10采用混输技术还可以降低井口回压增加老油田生产后期的产量油气管网输送 欧美一些发达国家自二十世纪初开始进行石油工业多相混输技术的研究欧洲北海油田的大规模开发极大的促进了这一技术的发展法国挪威等欧洲产油国相继发起了多相混输研究项目多相混输泵水合物抑制措施等方面开展了大量的工作法国挪威都成立了专门的研究机构美国和加拿大的一些机构也一直从事多相流的研究当今世界石油工业多相流研究的中心在欧洲［３］我国对混输技术的研究已取得多相流试验环道及中试基地建设多相流量计标定装置建设等成果九五一些石油公司和科研院所结合沙漠油田和滩海油田的开发已有数条混输实验管线投产运行2002年深海油田多相混输技术仍将被视为对降低石油工业油气生产成本极具吸引力的一项技术２ １４．５ ５．０ ８０．０ ４９０ １６３２６５ １９７７ Ｓｔａｔｆｊｏｒｄ ３０ ３０９ １２．０ ２．５ －－ －－ －－ －－ １９８７ ＣＡＴＳ ３６ ４００ １７．２ １１．０ ８．４ －－ －－ －－ １９９３ Ｖｉｋｉｎｇ ２８ １３８ １２．０ ７．０ ２７．０ ８１０ ３３３３３ －－ －－ Ｔｒｏｌｌ ３６ ６７５６ １８９５８ ３周 1978澳 大 利 亚North RanKin 4013411.0 6.2 46.7 7608 6138 24h 1986 Michigan 30/20 130 9.0 -- 28.3 795 35597 -- -- Cameron System -- 215 -- -- -- -- -- -- -- Blue Dophine 36 116 -- -- -- -- -- -- 1975 MOPS 24 93 -- -- 7.1 143 49610 -- -- 美国Galyeston HI 24 166 9.9 -- 6.5 <800 8125 -- 1978 加拿大Sable Island 24 257 9.9 6.0 8.5 -- -- -- -- 印尼 Bekapai 12 42 -- -- -- <300 -- -- 1976 利比亚 Zelten 36 170 5.41.8 11.3 12700 890 4h 1978 锦州20-2 12 516.0-6.5 5.50-5.51.2 600 2000 -- -- 中 国东海平湖14385 7.8-7.54.51.33004300----油气水多相混输技术主要包括多相流动压降计算及增压多相分离以及多相流动控制技术等理论和实验对多相流科学的研究表明各种流型的发生和转变多相流量因此本课题来自国家高技术发展计划(863计划)青年基金项目(No.2002AA616050)浅海石油开发多相混输动态监测用电容传感器的研制 １．２ 油气混输过程的关键技术及研究概况 油气水多相混输技术的开发与应用主要涉及以下几个关键技术多相流动压降计算及增压１．２．１ 多相管流特性研究 国际上近二十年来多相流动与传热的动态特性研究是十分活跃的前沿课题波动换热设备的设计油气水三相流动是比两相流动更为复杂的流动现象流动状态的非平衡性和多值性同时所引发的流型变化特征与各相的物性流动参数给问题的深入研究带来了很多困难传热学包括数学模型的建立预测等方面困难重重包括各种不同类型的油气水三相流介质的配置系统各重要流动参数的计量都呈现很大的难度理论研究工作识别管流数学模型的建立其物性参数的确定即流型变化的规律持液律的测量水合物形成条件预测和抑制技术油气水多相管流实验技术油气水多相混相输送泵的研制及管线的故障诊断技术等压降计算是确定多相管流管径因此准确计算沿线压降具有重要的意义其计算的准确性直接决定了压降计算的准确性主要是因为多相管流中不仅存在气体或液体与管壁之间的相互作用目前多相管流的沿程摩阻系数还只能采用以实验为基础的经验或半经验关系式来计算气液界面的摩阻系数计算方法不同分层流还要用到气液界面之间的相互作用是一种集常规泵和气体压缩机性能于一体的增压设备另外， 混输泵需适应油田的恶劣环境，在无人照看情况下能够实现长期运转上述各种原因导致油气混输泵技术的复杂性和多变性，给混输泵的研究和开发带来了极大的难度国际上已开发出的混输泵主要有下列几种液环泵离心泵膜片泵和喷射泵等[5]１．２．３ 多相计量 精确计量多相流的难度要比单相计量大得多流动粘度但多相计量在以下几个方面与单相计量作用方式存在着差异［６］： （１） 各相并非混合均匀 （２） 各相以不同的速度流动，各相之间存在着界面效应和相对速度，相界面在时间和空间上变化比较大，液相和气相具有不同的流动速度各相混合时，结果是难以预料的，粘度和总量会发生变化气体能从溶液中析出或者溶解在液体中，蜡和水合物将在流体中沉淀其特征参数也比单相流系统多流体特性 为解决以上难点，关键是建立合理的测量模型，重视特征参数的选取，选用可靠的仪器，应用先进的数据处理方法１．３ 空泡份额检测在油气混输中的作用 多相流科学的理论和实验研究表明压降计算和多相计量这三大关键技术的重要参数之一各种流型的发生和转变多相流量空泡份额α定义为气相所占据的流道的横截面积的份额[9]AA G=α (1-1) 或空泡率相分率等多相流动系统中空泡份额的检测始终是测量领域的一个难点资料表明但这些结果都有其特定的应用场合在实际工程应用中１．３．１ 空泡份额与流型识别 流型及其转变特性的研究是多相流研究中最重要的问题之一传质传热系数是两相流领域从实验科学走向理论科学的前提［８］而且还与介质的压力流道的几何形状道的安装方式有关使本来就很复杂的流体力学问题更加难解流型过渡资料表明大多数的研究人员选用压力信号进行应用先进的数学理论进行处理和分析这是由于压力信号易于采集压差较为成熟但是这种方法存在着一定的局限性另外压力信号随流动变化易受干扰［１０］本文依托国家计划研究课题在前人研究的基础上并进行实测实验研究各种流型中空泡份额的波动特性 １．３．２ 空泡份额与段塞流的预报和控制 具有强烈间歇性的段塞流是油气混输管道中最常见的流型之一当气体流过管道中波动的液体表面这种非均相流动会产生段塞流现象液体充满管道的截面并作为一个整体沿着管线向前运动或液塞即以气团流在管路终点流出的气对管线下游油气加工设备的工作产生不利影响因此在实际生产中必须防止段塞流的形成［１１］研究人员必须对段塞流的特性频率 段塞流的预测是油气水混输技术研究的关键并在此基础上结合其它工艺条件对段塞流的成因做出分析１．３．３ 空泡份额与流速和流量的测定 多相流流速和流量的在线测量一直是一个急需解决而长期以来又未能解决好的难题［１２］因而可以简化集输流程美国法国俄罗斯等二十多家公司和科研机构进行了油气水多相流量计的研发工作但实际过程的计量精度与工业应用要求还存在一定的差距从应用情况来看在合适的流态条件多相流量计所能达到的各种单相流量的计量准确度一般为１５％[3]ÕâÖÖ·½·¨ÊÇÓòãÎö³ÉÏñËù»ñµÃµÄÏà·Ö²¼Í¼ÏñΪ»ù´¡½øÐÐÏà¹Ø¼ÆËã²â¶¨·ÖÏàËٶȵÄ其基本过程如图１－１所示以获得的图像（或像素）为相关信号源再将空泡份额值与各相速度信息和密度函数相结合即可测得混输流体各分相流量和总流量（１）快关阀门法(Quick Close Valve, QCV) 快关阀门法是直接测量空泡份额的一个最常用的方法多采用电磁阀同时关闭这两个阀门这种方法准确有效此法的主要缺点是测量时要切断流体的正常流动实时检测（２）射线吸收法 利用射线法测量空泡份额始于上个世纪五十年代由于光电效应射线强度将发生衰减设初始强度为0I 的射线源穿过厚度为Ｌ其强度服从Beer 定律使用时首先测量通道充满气体和液体时所接收到的强度LI I G 和则可得到空泡份额α与LG I I I 和GL I I I I ln ln ln ln −−=α⊃™∉⇓⊃™∉⇓≡⊆ℵ ©℘⊃™∉⇓⊄∞…⌡•♦″®ℑ↵↵∏⊕⇑•⇑∂↔∂∪∉÷⇓⊇≠©℘⊇±±¬∠ ″⊃∪ϒ∇∉÷〉∝⊗÷ℵ×⊇♥⊆←⊇±®∩∅ …⇔÷〉°≡≠⌠(3)⊃™∉⇓⊃′⊃™•♦ ⊃™∉⇓⊃′⊃™•♦√ ®♠©∠∝±↔″↵•√⊗⇐ℑ↵×↔∝⇑÷∝⋅©∉⇓≥⊃θ ∩∝⊗•∉∫⊃∉″⊃®≈∂♦⊗⇐ℑ↵∝⊗≠®⋅©)cos 1(96.11)('θθ−+=E EE ¶øÇÒͨ¹ý×¼Ö±Ô´ÉäÊøºÍ̽²âÆ÷¼´¿Éֻ̽²âÔÚijһÌØÊâµã´¦±»É¢ÉäµÄ¹â×ÓÕâÒ²ÊÇÖÐ×ÓÉ¢Éä·¨Êǽ«ÐèÒª²â¶¨µÄͨµÀ½ØÃæ²¼ÖÃÓڿ쳬ÈÈÖÐ×ÓÉäÊøÖпÕÅݷݶîÖµ¿É°´ÏÂʽ¼ÆËãN(0), N(1), N(1和α时中子接收器的计数值电学法又分为阻抗法和电阻探针法在不同的空泡份额下用阻抗法不仅能得到气液两相混合物的平均空泡份额还可用于非定常流动的瞬态测量杂质的引入而产生的液相介电常数变化的影响价格低所以一直受到研究者的关注电阻探针法测量空泡份额的原理是基于气液两相电导率的不同如果探针的接触面落在气相中如果探针的接触面落在液相中于是在稳定的两相流中∫∞→=TT dt t f T)(1limα［当探针在气相时当探针在液相时上式表明如果探针所在点出现气相的概率越大因此用电阻探针法测得的是局部某点的时间平均空泡份额随着光学技术的发展液滴直径和流动速度已取得了很大进展现已有成熟的PIV 和PDA 测量仪器 此外，空泡份额的测量方法还有热学法［１９］，核磁共振法［２０］，微波法［２１］，超声法［２２］，支管旁路方法［２３］等除了快关阀门法外上述各种方法还没有一个方法可以普遍适用为了满足工程需要在线研究者们把空泡份额传感器的研制重点集中在简单灵敏１．５ 过程层析成像技术简介 过程层析成像技术（Process Tomography, 缩写为PT ）是指运用层析成像方法处理从末端传感器获得的数据过程层析成像技术来源于医学诊断中对人体的断面成像，它实际上是医学CT(Computer Tomography)技术在工程技术应用上的改进及发展ＰＴ技术在多相流领域的应用始于20世纪80年代中期，它以两相流或多相流为主要测量对象，运用图像重建技术显示过程参数的二维或三维分布状况在线和可视化对科学研究和生产实践都具有重要的作用１．５．１ ＰＴ技术的基本原理 与医学CT 技术一样 在图1-2所示坐标系统中),(ˆ),(∫∫∞∞−∞∞−==dz r f dz y x f p θ (1-3) 即 φφθπθπdld l pl r r f ∂∂−−=∫∫∞∞−02)cos(121),(ˆ (1-5) 式(1-4)称为Radon 变换式（1-4)实际上就是射线投影图1-2 Ｒａｄｏｎ公式中所用的坐标系统 Fig.1-2 Reference coordinate of Radon equation过程层析成像的实质是即实现Radon变换重建出反映物场在某一二维截面上或某一三维空间上的分布信息的图像１．５．２ PT 系统的组成 PT 系统主要由三大部分组成传感器控制及数据采集系统如图１－３所示［２７，２８］这些阵列可在CPU 的控制下依次在一定空间内建立其敏感场检测到的信息反映了其敏感空间内不同区域中被检测物场的物理化学特性并以一定的格式发往计算机图1-3 PT系统结构框图 Fig.1-3 Scheme of PT system计算机依据得到的反映物场特性参数分布的投影值使用特定的图像成像算法重建出反映物场参数分布的图像采用一定的信号处理方法获得所需参数及结果变化的状态，要求PT系统不仅要具备非接触或非侵入方式的在线获取物场信息的能力，还应具备良好的实时信息处理功能匹配化学特性及其工作参数条件，以及对周围干扰环境（电磁干扰 （３）从重建图像信息中提取与被测物场及其运动变化有关的特征参数，实现对被测物场做出定性和定量的评估，并可以对相应的过程实现调节和控制图像重建难度大PT系统还具有从重建的图像中提取与两相流流动有关的特征参数（如流型作出定性或定量的评估１．５．３ ＰＴ技术的分类与选择 经过十多年的研究和发展基于不同原理的PT系统相继问世PT技术可分为Ｘ射线层析成像射线层析成像核磁共振层析成像光学层析成像超声层析成像电阻层析成像电阻层析成像技术在环境监测中有成功应用核磁共振和超声层析成像等从医学CT中过来的PT技术在小型化和实时性方面也已取得了一些进展［１２］有待进一步完善和发展表1-2 几种常见的层析成像方法比较 Table 1-2 Comparison of some PT technologies检测原理 介电常数 电导率 电导率 磁导率 衰减 分子的旋磁率 干涉衰减 反射低 中向工业应用发展（１）实时性这就要求PT系统的成像速度必须要高（一般应大于50帧／秒）凝固 （２）适应性便于现场安装湿度和压力具备信号远传通信能力要求PT系统能够长时间稳定运行 （４）经济性便于大量推广使用要求仪器具有防爆对人体无伤害（６）测量精度满足工业应用要求易于维护图1-4表示了对PT技术的选择应用流程需要对含铁物质独立成像吗电极可以接触流体吗能透光吗可以加含铁的示踪物质吗Y图1-4 PT 技术传感器的选择［４８］ Fig.1-4 Sensor selection method of PT technology１．５．４ ＰＴ技术在工业上的应用 国内外文献报道风力输送系统及粉体浓度监测多相流动监测向着工业应用发展并逐渐显示出它的优越性将PT 技术用于流型可视化检测和流型辩识１．６ 电容层析成像技术 电容层析成像技术(Electrical Capacitance tomography, 简称ECT)是较早发展起来的一种PT技术速度快适用范围广和安全性能佳等优点也是最有工业应用前景的PT技术之一随后改进成为12电极ECT系统同期，美国能源部摩根城研究中心研制开发出了１６电极电容层析成像系统用于流化床中的空隙率分布研究［５５，５６］，他们称之为德国汉诺威大学［５７］(Hannover University)荷兰代夫特理工大学(Delft University of technology)［６０］和我国的清华大学，浙江大学等单位都对ECT技术的研究和发展做了大量的工作 １．６．１ 电容层析成像的组成 ECT系统主要由电容传感器如图1-5所示检测电极外壳和导线等部分组成数据采集系统将这些电容值转化为数字量并传送给计算机并根据成像结果分析提取过程参数电容传感器图1-5 电容层析成像系统的基本组成 Fig.1-5 Scheme of ECT system１．６．２ ECT 的理论基础及图像重建算法 电容层析成像的理论基础是基于电磁场理论的Possion 方程［２９[]0),(),(0=Φ∇•∇y x y x εε (1-6) 边界条件为,0|),()12,,2,1(,0|),()11,,2,1(,|),(),(),(),(sj iy x y x y x y x j ij y x i U y x ϕϕϕL L ),(y x ε为管截面上介电常数分布j i ΓΓ,为电极上点的集合由任意两个电极构成的电容ji C ,jd y x y x Q jΓ•∇=∫Γ),(),(0ϕεεj Γ为包围电极j 的空间曲面 ∫ΓΓ•∇==jj j i d y x y x UU Q C ),(),(0,ϕεε (1-7)对于n 电极电容层析成像系统共可获得的独立电容测量值N 为电容层析成像就是根据测量所得的N 个电容值来求取反映多相流体被测区域内相介质浓度分布的电介质分布函数),(y x εÕâÒ»¹ý³ÌʵÖÊÉÏÊǶԷ½³Ì×é(1-4)的逆问题求解图像重建算法有多种［２５，６２－６８］，最常用此外还有基于迭代的算术重建算法MORÈ˹¤Éñ¾-ÍøÂç·¨µÈÓ¢¹úProcessTomography limited 公司所研制的PTL-300型电容层析设备采用的就是LBP 算法［６９］速度快早期的LBP 算法又称0/1算法图像失真严重采用全灵敏度信息为减少LBP 算法的边缘效应但门限滤波处理是与流型密切相关的迭代算术重建算法是将LBP 算法所获得的图像作为初始值以及电容敏感场灵敏度信息来修改介质分布与LBP 算法相比但重建时间则大大加长常用于仿真计算它为定量的重建两相流介质分布提供了可能二维有限元电容仿真器根据介电常数分布计算出对应的电容仿真值调整n个参数给出新的介电常数分布直至误差最小描述介电常数分布的参数值远小于电容测量值重建时间越长应用MOR法的关键是实际流型的参数化其精度比LBP算法高得多 查表法利用已知流型的介电常数分布计算出一系列电容值当取得测量值后哪一组电容值与测量值的差别最小这种方法与应用场合有关即可迅速得到分布若实际出现的流型在表中查不到因此该法需要大量的基础数据它是训练一种能将电容测量值转换为两相介质分布的算法或网络但训练好以后网络相应速度相当快对环状流但对复杂的介质分布 １．６．３ ECT系统研究使用中的问题 作为最早开发应用的PT技术之一如气液燃烧火焰成像油气水三相流相分布成像和流型辨识［１２］ECT技术具有安全低成本和非浸入等优点抗杂散电容电路和微小电容检测电路的设计和改进但由于软场效应的影响造成ECT系统的成像质量难以令人满意对于流动参数的精确计量要求还有相当大的距离Is 2D impedance tomography a reliable technique for two-phase flow?因此ECT技术还必须解决以下问题２． 微电容测量电路的进一步改进和提高４． 与其他ＰＴ技术相结合拓展其使用范围１．７ 本文的主要工作及创新点 １．７．１ 主要工作内容 基于两相流科学理论和油气多相混输工程实践863计划(No.2002AA616050)ÖصãÑо¿Á˵çÈÝÐÍ¿ÕÅݷݶ¸ÐÆ÷µÄ½á¹¹ÑÐÖƳöÐÂÐͶ༫°åÕóÁÐʽµçÈÝ´«¸ÐÆ÷ºÍ΢µçÈݼì²âµç·ÀûÓÿÎÌâ×éËùÑÐÖƵĿÕÅݷݶî²âÁ¿ÏµÍ³ÔÚÖ±¾¶Îª125mm的油气两相流实验环路上对油气混输过程中水平管和倾斜管的流动特性作者负责完成的工作为运用ANSYS有限元分析软件对电容传感器的结构进行了仿真与优化(2) 基于仿真分析结果(3) 研制成功电容检测电路及数据采集系统(5) 根据实验数据处理结果为进一步用于流型预测监控提供参考(1)在二维有限元模型的基础上基于所建立的三维模型主要仿真结果为对于内径为１２５ｍｍ的内置式传感器外置式传感器由于管壁的影响相邻极板间的电容变化量出现负值(2)针对油气混输过程该成果可用于实时在线检测油气两相流动管路中的空泡份额传感器为12极板内置式结构具有两组电。
湍流长度尺度英文
湍流长度尺度英文Turbulence Length ScalesTurbulence is a complex and fascinating phenomenon that has been the subject of extensive research and study in the field of fluid mechanics. One of the key aspects of turbulence is the concept of turbulence length scales, which refers to the range of different-sized eddies or vortices that are present in a turbulent flow. These length scales play a crucial role in understanding and predicting the behavior of turbulent flows, and they have important implications in a wide range of engineering and scientific applications.The smallest length scale in a turbulent flow is known as the Kolmogorov length scale, named after the Russian mathematician and physicist Andrey Kolmogorov. This length scale represents the size of the smallest eddies or vortices in the flow, and it is determined by the rate of energy dissipation and the kinematic viscosity of the fluid. The Kolmogorov length scale is typically denoted by the Greek letter η (eta) and can be expressed as η = (ν^3/ε)^(1/4), where ν is the kinematic viscosity of the fluid and ε is the rate of energy dissipation.The Kolmogorov length scale is important because it represents the scale at which viscous forces become dominant and energy is dissipated into heat. Below this length scale, the flow is considered to be in the dissipation range, where the eddies are too small to sustain their own motion and are rapidly broken down by viscous forces. The Kolmogorov length scale is therefore a critical parameter in the study of turbulence, as it helps to define the range of scales over which energy is transferred and dissipated within the flow.Another important length scale in turbulence is the integral length scale, which represents the size of the largest eddies or vortices in the flow. The integral length scale is typically denoted by the symbol L and is a measure of the size of the energy-containing eddies, which are responsible for the bulk of the turbulent kinetic energy in the flow. The integral length scale is often determined by the geometry of the flow domain or the boundary conditions, and it can be used to estimate the overall scale of the turbulent motion.Between the Kolmogorov length scale and the integral length scale, there is a range of intermediate length scales known as the inertial subrange. This range is characterized by the presence of eddies that are large enough to be unaffected by viscous forces, but small enough to be unaffected by the large-scale features of the flow. In this inertial subrange, the energy is transferred from the large eddies to the smaller eddies through a process known as the energycascade, where energy is transferred from larger scales to smaller scales without significant dissipation.The energy cascade is a fundamental concept in turbulence theory and is described by Kolmogorov's famous 1941 theory, which predicts that the energy spectrum in the inertial subrange should follow a power law with a slope of -5/3. This power law relationship has been extensively verified through experimental and numerical studies, and it has important implications for the modeling and prediction of turbulent flows.In addition to the Kolmogorov and integral length scales, there are other important length scales in turbulence that are relevant to specific applications or flow regimes. For example, in wall-bounded flows, the viscous length scale and the boundary layer thickness are important parameters that can influence the turbulent structure and behavior. In compressible flows, the Taylor microscale and the Corrsin scale are also relevant length scales that can provide insight into the characteristics of the turbulence.The understanding of turbulence length scales is crucial for a wide range of engineering and scientific applications, including fluid dynamics, aerodynamics, meteorology, oceanography, and astrophysics. By understanding the different length scales and their relationships, researchers and engineers can better predict andmodel the behavior of turbulent flows, leading to improved designs, more accurate simulations, and a deeper understanding of the fundamental principles of fluid mechanics.In conclusion, turbulence length scales are a fundamental concept in the study of turbulent flows, and they play a crucial role in our understanding and modeling of this complex and fascinating phenomenon. From the Kolmogorov length scale to the integral length scale and the inertial subrange, these length scales provide valuable insights into the structure and dynamics of turbulence, and they continue to be an active area of research and exploration in the field of fluid mechanics.。
分汊型河道水流运动特性和污染物输移规律研究进展
分汊型河道水流运动特性和污染物输移规律研究进展顾莉;华祖林;褚克坚;刘晓东【摘要】The relevant researches on the flow characteristics and pollutant transport laws in braided rivers were reviewed. They were summarized from four aspects, namely the flow characteristics of bifurcation, confluence and the whole braided river, and the pollutant transport laws in braided rivers. Firstly, as to the flows at the bifurcation and confluence of braided rivers, the research achievements from the ID and 2D flow characteristics including energy loss, water level variation, flow separation and so on to the 3D flow structure and turbulent characteristics were introduced. Secondly, the flow characteristics of the whole braided river were described by means of field tests, laboratory tests and numerical simulations. Thirdly, the relevant researches on the pollutant transport laws in braided rivers were reviewed and analyzed, and the numerical simulations were found out to be the main method. Finally, some further problems about the flow characteristics and pollutant transport laws in braided rivere were put forward, especially the experimental studies on the pollutant transport mechanism under different discharge modes, pollutant densities and braided forms.%对分汊型河道的水流运动特性和污染物输移扩散规律的相关研究进行综述,分别从分汊型河道中分汉口、交汇口、整个分汊河道的水流特性及分汊型河道中的污染物输移特性等4个方面进行总结.介绍分汉口和交汇口处的水流从其能量损失、水位变化、水流分离等一维、二维过流特征到三维流动结构和紊动特性的研究过程；从野外现场试验、室内物理模型试验和数学模型模拟等角度出发阐述了整个分汊河道的水流特性；认为污染物在分汊河道中的输运规律研究主要集中在数值模拟上,并进行了回顾和分析；提出分汊河道水流水质输移特性研究中一些有待深入探究的问题,尤其亟待加强不同排放方式、不同污染物密度和不同分汊形态下污染物输移机制的试验研究.【期刊名称】《水利水电科技进展》【年(卷),期】2011(031)005【总页数】7页(P88-94)【关键词】分汊河道;水流运动特性;污染物输移;综述【作者】顾莉;华祖林;褚克坚;刘晓东【作者单位】河海大学浅水湖泊综合治理与资源开发教育部重点实验室,江苏南京210098;河海大学环境学院,江苏南京210098;河海大学水资源高效利用与工程安全国家工程研究中心,江苏南京210098;河海大学浅水湖泊综合治理与资源开发教育部重点实验室,江苏南京210098;河海大学环境学院,江苏南京210098;河海大学水资源高效利用与工程安全国家工程研究中心,江苏南京210098;河海大学浅水湖泊综合治理与资源开发教育部重点实验室,江苏南京210098;河海大学环境学院,江苏南京210098;河海大学水资源高效利用与工程安全国家工程研究中心,江苏南京210098;河海大学浅水湖泊综合治理与资源开发教育部重点实验室,江苏南京210098;河海大学环境学院,江苏南京210098;河海大学水资源高效利用与工程安全国家工程研究中心,江苏南京210098【正文语种】中文【中图分类】TV133分汊型河道是一种特定而时常遇到的河道形态,由于江心洲的存在,河道水流发生分汊现象,如长江中下游、珠江广东段、赣江、湘江、松花江、黑龙江、美国Mississippi河、非洲Niger河和Benue河等都时常遇到。
小流量自由跌水长度及消能研究
小流量自由跌水长度及消能研究IIAbstractThe geometric construction of free overfall is simple,but the flow is very complex .It flows with the complicated free surface.This flow problem with free surface has always been a hot research.This paper introduced the structure of the free overfall.And on the basis of understanding the research background,we reviewed the research status of Formula,experimental investigation and numerical simulation in the domestic and ing acrylic to make different size of sink,and this sinks made up the model.At the time of model experiment,under the different height of drop,carried out more groups of experiment including different flow to ensure the comprehensiveness and rationality of the experimental investigation.Now the hydraulics formulas mostly were empirical formula.In this paper,on the basis of summarizing predecessors'research results,put forward a fast and convenient formula to calculate the length of free overfall and validated ing software FLUENT to set up three-dimensional model in this paper,and a series of studies were carried out.⑴According to the projectile motion,we can deduce a formula to calculate the length of free overfall.The formulais 75KL A =,A is experience factor,the range is1.5~1.6;K is air resistance coefficient,1K =;is the kinetic energy correction coefficient,1α=;q is unit discharge ；H is the height of drop.⑵The VOF method is used to deal with the interface between gas and water.And it is combined with k ε turbulence model to simulate free overfall can get a very good effect.It fit well with the actual situation.⑶By analyzing the flow pattern,pressure distribution,velocity distribution,streamline distribution of water in the channel,we can judge that the numerical simulation method was reliable.⑷The comparison results of formula,model experiment and numerical simulation showed that the result of formula was very close to model experiment,the errors were 17.6%、22.4%and 14.6%between numerical simulation and model experiment.According to the previous experience and actual test conditions,this error was within an acceptable range.So the formula can be applied to practical engineering.⑸In order to reduce the destruction in the channel bottom slabs and banks,we can set stilling wall in the downstream to improve the rate of energy dissipation.In this paper, different height of stilling wall was set up in the proper bined velocity with dynamic pressure to choose the most optimal height of stilling wall.As for the model of this paper,choosing3cm high of drop was the optimal conditions.This result provided some design basis for practical engineering application in the future.Key Words：Free Overfall;Formula;Numerical Simulation;VOF Method;Height of Stilling WallIII小流量自由跌水长度及消能研究目录摘要 (I)Abstract (II)1绪论 (1)1.1跌水研究的背景 (1)1.2跌水研究现状 (3)1.2.1关于跌水长度的理论及试验研究 (3)1.2.2关于跌水的数值模拟研究 (4)1.2.3关于水垫消能的研究 (5)1.3目前研究不足 (5)1.4本文主要研究内容 (6)1.5本章小结 (6)2自由跌水模型试验 (7)2.1水力模型试验基本原理 (7)2.2工程背景 (7)2.3试验设备 (8)2.3.1试验水槽 (8)2.3.2测量设备 (11)2.4试验结果 (12)2.4.1下游未设置消力墙 (12)2.4.2下游设置有消力墙 (16)2.5本章小结 (21)3自由跌水公式推导 (22)3.1理论基础 (22)3.1.1临界水深的原理 (22)3.1.2水跌的原理 (23)3.1.3平抛运动原理 (24)3.2跌水长度公式推导 (25)3.3本章小结 (27)4自由跌水数值模拟 (29)4.1紊流数值模拟理论基础 (29)IV4.1.1流体运动研究方法 (29)4.1.2流体力学基本方程组 (30)4.1.3紊流数值模拟 (31)4.2模型构建及算法 (33)4.2.1模型的构建 (33)4.2.2边界条件及算法 (37)4.3数值模拟结果分析 (38)4.4多种工况模拟 (41)4.5本章小结 (44)5不同方法所得跌水长度 (45)5.1模型试验结果 (45)5.2公式推导结果 (45)5.3数值模拟结果 (46)5.4三种结果对比 (46)5.5本章小结 (47)6最优消力墙高度 (47)6.1不同消力墙高度下水力特性 (47)6.1.1各工况下临底流速 (48)6.1.2各工况下动水压力 (50)6.2最优消力墙高度 (53)6.3本章小结 (54)7结论与展望 (55)7.1结论 (55)7.2展望 (56)参考文献 (57)读硕士学位期间发表论文及科研成果 (60)致谢 (61)V1绪论1.1跌水研究的背景自由跌水广泛存在于我们身边的许多水利工程中[1-2]，人们利用其来建成各种过水以及泄水建筑物，以此来保护下游渠道、边坡以及建筑物的安全。