【作者】 崔宝玲；

【导师】 陈鹰； 朱祖超；

【作者基本信息】 浙江大学 ， 机械电子控制工程， 2006， 博士

【摘要】 汽蚀破坏是引起离心泵故障的主要原因之一，如何提高离心泵的汽蚀性能是流体机械研究领域的一个重要研究方向。另外，叶轮机械主要的能量转换是在叶轮中完成的，因此了解液流在叶轮内部的流动机理，对设计高效率的叶轮及离心泵的节能降耗有着重要的意义。本论文主要针对上面的问题进行了研究。 论文的主要内容如下： 第一章：介绍了提高离心泵汽蚀性能的措施及诱导轮研究的现状；概述了离心泵内部流动的研究进展及商用的CFD软件的发展及应用；在此基础上提出了本文的主要研究内容。 第二章：介绍了本文计算所采用的数值方法：给出了相对坐标系下三维N-S控制方程组的通量形式及S-A湍流模型；介绍了控制方程的空间离散和时间离散及时间项的四阶龙格库塔迭代法；介绍了计算加速方法，包括隐式残差光顺和全多重网格方法；并给出了收敛标准。 第三章：对诱导轮的汽蚀性能进行了分析，给出了单个及串联诱导轮的设计方法；基于雷诺时均Navier-Stoks方程和Spalart-Amaras湍流模型对所设计的单个及串联诱导轮进行了数值模拟计算，分析了单个及串联诱导轮内部的流动情况；并进行了试验研究。 第四章：提出采用引射器提高离心泵的汽蚀性能，对引射的理论进行了分析，并设计了引射器，对具有前置引射器的两台开式叶轮离心泵进行了实验研究，在不同引回流量的情况下进行了汽蚀实验研究。 第五章：给出了复合叶轮的设计方法，分析了离心叶轮内部的流动机理；对4个闭式的不同中短叶片数的低比转速复合叶轮进行了数值模拟和实验研究，分析了叶轮内部的相对速度场及压力场，揭示了不同中短叶片数对叶轮内部流动的影响；并对不同间隙的4长叶片及4长4中叶片的半开式复合叶轮进行了数值模拟，分析了间隙对于内部流动的影响。 第六章：对长、中、短相间的复合叶轮离心泵进行了数值模拟计算，分析了叶轮和蜗壳内部的流动情况，揭示了蜗壳对于叶轮内部流动的影响机理。 第七章：概括性地总结了本论文各章所得出的若干结论，并对目前存在的问题及今后的工作提出了具有指导意义的建议。更多还原

【Abstract】 Cavitation devastation is one of the main reasons to arise the malfunction of centrifugal pump. How to improve the suction performance of centrifugal pump is an important research aspect in the field of fluid mechanism. And the main energy transform is completed in impeller of impeller mechanism. So to know the flow principium in impeller is very significant to design high-efficiency impeller and to save the energy and cost. The researches were carried out on the above questions.The main contributions of this thesis are as follows:In chapter 1, the method of improving the suction performance of centrifugal pump and current research progress of the inducer were reviewed. The research progress of flow in centrifugal pump and the development and application of commercial CFD software were mainly described. The main research subjects were presented.In chapter 2, the numerical methods adopted in this paper were introduced. The N-S controlling formulation for relative velocity in rotating frame of reference and the S-A turbulent model were given. The spatial and time discretizations of the N-S controlling formulation were introduced. And four-stage Runge-Kutta iterative method of time discretization was introduced. Then, the accelerating computational methods including implicit residual smoothing and full multigrid strategy were presented. The convergence criterion was given.In chapter 3, the suction performance of inducer was analyzed and the design methods of single and two-phase inducers were given. Based on the Navier-Stokes equations and the Spalart-Allmaras turbulence model, three-dimensional turbulent flow in single and two-phase ones designed was simulated numerically. The relative velocity and static pressure in them were analyzed. And the experiments of the centrifugal pump with inducers were carried out.In chapter 4, using the jetting device to improve the suction performance of centrifugal pump was presented. The theories of jetting were analyzed and the jetting device was designed. Experimental studies on two centrifugal pumps with jetting device were carried out. And the cavitation tests were carried out at different feed-back capacity.In chapter 5, the design method of complex impeller was given and the flow mechanism of centrifugal impeller was analyzed. The simulative and experimental researches were carried out on four low-specific complex impeller with different number of mid and short splitter blades. The relative velocity and pressure distribution in them was analyzed. The influence mechanism of the number of splitter blades on the flow in impellers was disclosed. And the flow field in the semi-open four-long-blade impeller and four-long four-mid-blade impeller with different clearance was simulated numerically. The influence of clearance on the flow was analyzed.更多还原