离心泵叶片出口边倾斜角对压力脉动的影响

Effect of oblique angle of blade trailing edge on pressure fluctuation in centrifugal pump

为研究叶片出口边倾斜角对叶轮与蜗壳由动静干涉作用而引起压力脉动的影响,在保证叶轮基本参数和叶片安放角变化规律不变的情况下,通过改变叶片出口边倾斜角而设计了2种计算方案.采用SST湍流模型、SIMPLEC算法和滑移网格技术,分别对不同叶片出口边倾斜角的叶轮匹配同一蜗壳的离心泵进行全流道非稳态数值模拟,得到不同叶片出口边倾斜角的离心泵外特性及压力脉动特性,并对其进行分析.计算结果表明:随着叶片出口边倾斜角的减小,泵高效区加宽;在小流量工况至设计流量工况时模型1,2的扬程流量曲线接近,在设计流量工况至大流量工况时模型2的扬程增大;2种叶片出口边倾斜角的离心泵中监测点处的压力脉动规律相同,呈周期性变化;较小叶片出口边倾斜角的离心泵中蜗壳内及隔舌处的压力脉动波动幅度减小,高频脉动成分减小.分析结果可为离心泵叶轮的设计提供理论参考.

Two impellers,in which the blade trailing edge is with different oblique angles but the blade angle profile remains unchanged,were designed for a centrifugal pump to study the pressure fluctuation features caused from the impeller-volute interaction.The unsteady,three-dimensional turbulent flow in the pump was simulated by using the SST turbulence model,SIMPLEC algorithm and sliding mesh technique in this paper.Then the performance and pressure fluctuations in centrifugal pumps with those impellers were obtained.It was demonstrated that the pump keeps a relative higher efficiency in an extended flow rate range with decreasing oblique angle;additionally,the pump heads are close to each other for the two impellers at the part-loading and design conditions,however,the heads increase at high flow rates.The periodic features in pressure fluctuation are the same for the two impellers,however,the amplitude of the fluctuation and high-frequency components are reduced in the volute and near its tongue.These results can provide a useful reference for the design of centrifugal pump impeller.