高速离心叶轮内部流动的数值模拟

Based on the Navier-Stokes equations and the Spalart-Allmaras turbulence model, three dimension turbulent flow fields in low-specific-speed high-speed centrifugal impellers with eight blades are calculated and analyzed numerically whose three types are closed, half-open and open. It is found that there all exist back flow region in three impellers, the front axial clearance between impeller and casing in half-open impeller can improve the flow in it, and the static pressure in impellers rise gradually from blade inlet to outlet whose contours are almost alone the circumferential orientation and the pressure coefficient of open impeller is highest. The experiment and simulation results show that the axial clearance of impeller and the back flow in it have important influence on the performance of pump. The experimental results also show that the head coefficient of open impeller is highest, eight-blade closed and half-open impeller with splitter blade can’t solve the small-flow instability of low-specific centrifugal pump and open impeller centrifugal pump can transport the small-small media with small capacity work range.