【作者】 付强；

【导师】 朱荣生；

【作者基本信息】 江苏大学 ， 流体机械及工程， 2006， 硕士

【摘要】 随着我国经济快速发展，对电力供应的需求越来越大。我国电力结构是以火电为主，而且今后相当长的时间内这种现状不会改变。火电是最大的耗煤用户，近年来，能源日益紧张，煤炭价格也在不断上涨，因此，如何提高热效率以达到节煤的目的，成为众多电厂最关心的问题。采用疏水泵连接的给水回热系统是提高电厂效率的有效措施，但由于低压加热器疏水具有吸入压力和吸入温度比较高的特点，从而造成疏水泵的工作条件较差。现有疏水泵品种单一、造型困难，并且很容易发生汽蚀现象，使维护工作量增加，只有少量火电机组采用疏水泵的连接方式。因此，开发品种齐全、汽蚀性能好的疏水泵是十分必要的。 本文将近年来快速发展的CFD技术应用在低比速疏水泵抗汽蚀性能的研究中，应用CFD软件FLUENT中的标准κ-ε湍流模型对低比速疏水泵内部三维湍流数值模拟，得到同一设计工况下四种不同长短叶片形式叶轮内流场的速度和压力分布。结合试验数据，初步分析流场分布与汽蚀关系，为疏水泵优化设计提供基础参考。 本文的主要工作如下： 1．系统概述了前人在汽蚀基本理论和改善离心泵汽蚀性能方面的研究成果，归纳总结国内外在离心泵抗汽蚀性能设计领域的进展。 2．利用Pro／E三维实体造型软件进行叶轮实体造型工作，在造型过程中，根据后续计算的实际要求，将叶轮构造成具有周期性边界条件的单流道形式。 3．结合CFD软件FLUENT对所设计的4种叶轮在相同的设计工况下进行三维不可压湍流场的数值模拟。在数值模拟的前处理工作中，将Pro／E造型的叶轮实体导入GAMBIT生成流动区域，在利用非结构网格对流动区域进行网格划分，并指定边界类型。 4．通过计算结果与试验数据综合对比分析表明，将CFD技术应用于离心泵的设计中，对于改善电厂疏水汽蚀性能具有良好的效果。更多还原

【Abstract】 As natinal economy is developing rapidly, electric power will be in need more and more heavily. Our power structure is mainly heat power, which will be not changed in very long time. Heat power is the biggest coal consuming user, energy has been become more and more short recently, and price of the coal has shown a continuas up-trend, therefore ,how to increase heat efficency to save coal is focused by many power plant. The effective means for increasing the efficiency of power plant is to connect the extraction feedwater system with drainage pump. But the running conditions of drainage pump is bad, because the working substance in drainage pump is generally low pressure heater drainage which is of features such as high back pressure and suction temperature. Species of the drainage pump are single and mold making difficult, and cavitation is apt to occur which makes the amount of maintenance work inereased, so only few heat power units take drainage pump as attended modle. Therefore, it is very necessary to develop more exellent drainage pump with more specics and more cavitation.In this paper, the CFD technique which grows fast recently is applied in the study of anti-cavitations performance. The 3D turbulent numerical simulation for the low specific speed centrifugal pump where clear water flow in by N-S equation \RNG k- ε turbulent model and CFD software, and the velocity and pressure distribution of three kinds of blades with different shape. Combining with experimental findings, the relation between distribution of flow field and cavitations is analyzed and foundational reference is brought up for the perfection of the theory on low specific speed centrifugal pump and optimum design. The main work is outlined as following:1. Summarizing the research result on cavitations fundamental theory and the improvement in cavitations performance of the centrifugal pump, generalizing the advancement in anti-cavitations design.2. RO/E software is used to make the impeller entity. In the process of modeling, impeller has been constructed to different shapes such as whole flow passage and single flow passage.3. Combining with FLUENT, numerical simulation of the 3D incompressible flow field for four kinds of impeller which have been designed at the same design work condition according to actual qualification in later calculation, at pre-treatment of the numerical simulation, impeller entity which is made by PRO/E software is led to更多还原