关键词: 离心叶轮; 流场响应; 压力脉冲; 数值求解; 时空分布 

Abstract: In order to investigate the flow response of centrifugal impeller to intake pressure pulse, a flow-field analysis code for turbomachinery based on multi-block structured grids was developed independently, according to the deducted HLLC fluxes of convection terms in the relative coordinate system. Firstly the numerical examples of transonic Krain impeller and a subsonic radial impeller were carried out. The calculated performance curves and surface pressure distribution show favorable agreement with the data from test and commercial software, and furthermore, the code possesses a higher computing speed than the commercial software. Then taking the radial impeller as the research object, the flow responses to different inlet pressure pulses were simulated. The results indicate that, the upstream and downstream flow fields will be more non-synchronous when the pulse becomes sharper, which causes the delay of peak value moment of outlet mass flow and aerodynamic moment, and furthermore, makes the time-space distribution of pressure lose the symmetry axis of time. The characteristic of space distribution of blade load does not change with the variation of pulse width and time marching. The wider the pulse is, the longer the flow field changes, which causes the peak value of load to deviate further from the steady state. The space distribution of density variation is similar at different times.

Key words: Centrifugal impeller; Flow response; Pressure pulse; Numerical solving; Time-space distribution