长中短叶片离心叶轮内部流动的数值模拟

1引言随着宇航技术的飞速发展,液体火箭发动机的燃料剂和氧化剂离心泵向高压、高速、高效化发展。为了减轻泵的重量,使结构紧凑,提高泵的功率密度,离心泵的单级扬程和转速要高,因此其比转速较低。但比转速较低的离心泵效率也较低,而且很容易出现小流量工作不稳定性。因此设计具

Numerical simulation of inner flow field in centrifugal impeller with long,middle and short blades

The Navier-Stokes equations and the Spalart-Allmaras turbulence model are adopted to simulate the inner flow field in high-speed complex centrifugal impellers with eight and twenty-four blades, respectively. The relative velocity and pressure distributions are analyzed and compared in the flow channel of two impellers under small-flow and design-flow condition. It is found that the velocity distribution of inner channel and outlet in complex impeller with four-long, four-middle, sixteen-short blades are more uniform than that with four-long, four-middle blades. And the middle and short blades can increase the suction-side pressure and prevent liquid separation from suction side in complex impellers. Through the experiment and simulation, it is validated that the back flow in impeller channel is a key factor which affects the efficiency and small-flow instability of low-specific centrifugal pump and centrifugal pump with closed complex impeller with long, middle and short blades can be used to deliver small-flow high-head liquid media.