复合叶轮离心泵数值模拟与优化设计研究

发布时间：2018-04-01 07:45

本文选题：离心泵　切入点：低比转速　出处：《扬州大学》2014年硕士论文

【摘要】：低比转速复合叶轮离心泵具有流量小、扬程高、结构紧凑、维修方便等特点,在我国石油化工、轻工业和航空航天等领域得到了广泛的应用。鉴于其广泛的用途,研究离心泵的安全稳定性和经济高效性就显得尤为重要。本文从内流场的角度探究具有良好性能的复合叶轮离心泵。设计了3副具有相同长叶片不同短叶片的复合叶轮,利用三维湍流数值模拟的方法,分析了转速变化对离心泵内、外特性的影响、复合叶轮离心泵瞬态特性以及叶轮叶片最优开槽方式。主要开展的工作和取得的成果如下： (1)分析了大量国内外关于复合叶轮离心泵设计、水泵变转速运行试验、离心泵瞬态特性模拟以及旋转机械中流动控制技术的应用的研究成果,并进行了总结,提出了论文的研究方向。 (2)利用平面势流叠加理论分析了叶轮内部流动特性,并比较了无粘流体流动与粘性流体流动的差异。探讨了低比转速高速离心泵在多种力的作用下叶轮出口靠近叶片背面处发生脱流现象的原因。为了改善这种状况,设计了3副具有相同长叶片、不同短叶片的复合叶轮及配套蜗壳。 (3)利用三维湍流数值模拟方法,对3副复合叶轮离心泵不同转速下的内、外特性进行对比分析,探讨了转速变化对复合叶轮内、外特性的影响,分析了由于转速增大导致的牵连离心加速度、相对加速度和科里奥加速度及速度环量增大而引起的叶槽内流体质点相对速度矢量向压力面偏转的现象。结果表明随转速增大,质点相对速度矢量偏转变大,无因次性能曲线偏移量增加。 (4)利用正交试验设计法,研究了开槽的位置Df、径向宽度Wl及角度β3对水泵效率的影响,寻找能够提高水泵效率的合理叶片开槽方式。结果表明在0.37(D1+D2)处开2mm径向宽度的槽使水泵效率得到明显提高。 (5)为研究复合叶轮离心泵瞬态特性,对3副复合叶轮分别在3种流量工况下进行了非定常流动计算,发现不同工况下随着叶轮的旋转泵内流场及泵出口压力均发生周期性变化。从频域特性图看出C叶轮压力脉动幅度比其它两副叶轮的脉动幅度大,3副叶轮出口压力脉动幅度都表现出随着流量增大而增大的趋势。
[Abstract]:The centrifugal pump with low specific rotation speed has the characteristics of small flow , high lift , compact structure and convenient maintenance . In view of its wide application , it is very important to study the safety and economic efficiency of centrifugal pump .

( 1 ) The research results of centrifugal pump design , pump variable rotating speed running test , centrifugal pump transient characteristic simulation and flow control technology in rotary machinery are analyzed and summarized , and the research direction of the paper is put forward .

( 2 ) The internal flow characteristics of impeller are analyzed by means of plane potential flow superposition theory , and the difference between non - stick fluid flow and viscous fluid flow is compared .

( 3 ) By using three - dimensional turbulent numerical simulation method , the internal and external characteristics of 3 pairs of compound impeller centrifugal pumps are compared and analyzed , and the effect of rotating speed change on the inner and outer characteristics of the composite impeller is discussed . The phenomenon of the relative velocity vector of the relative velocity vector of the fluid particle in the cascade caused by the increase of the rotating speed is analyzed .

( 4 ) The influence of the position Df , the radial width Wl and the angle 尾 3 on the efficiency of the water pump is studied by using the orthogonal test design method . It is found that the efficiency of the water pump can be improved obviously at 0.37 ( D1 + D2 ) .

( 5 ) In order to study the transient characteristics of the composite impeller centrifugal pump , the unsteady flow calculation is carried out for 3 pairs of composite impellers under 3 kinds of flow conditions . It is found that the flow field and the pump outlet pressure in the rotary pump of the impeller change periodically under different working conditions . As can be seen from the frequency domain characteristic diagram , the pressure fluctuation range of the C impeller is larger than that of the other two auxiliary impellers , and the amplitude of the pressure pulsation of the three sub - impeller shows a tendency to increase with the increase of the flow .

【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH311

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