总压畸变对离心压气机动静干涉非定常效应影响的数值研究

The impeller-diffuser interference phenomenon under inlet distortion of the centrifugal compressor has more intense unsteady effect，which directly affects the aerodynamic performance and stability of the compressor. In this paper，three-dimensional full channel unsteady numerical simulation of a high-load centrifugal compressor was carried out to study the influence of total pressure distortion on the unsteady effect of impeller-diffuser interaction. The results show that the disturbance of impeller-diffuser interference propagates upstream and downstream at the same time，and the channel flowability is reduced. The six intrinsic mode functions components of the static pressure signal at the impeller-diffuser interface capture the characteristic frequencies respectively，and the peak value of the 3rd order IMF component is about 0.44 main blade passing frequency，which is related to the aerodynamic instability. The Hilbert spectrum shows a stall precursor signal after 2.5 ms. The influence of total pressure distortion on impeller-diffuser interaction is as follows:total pressure distortion enhances the interference of radial diffuser to impeller，the unsteadiness of blade load after 50% chord direction increases，and the leakage flow of the impeller clearance overflows and develops horizontally，resulting in channel blockage. The enhanced interference of the impeller on the radial diffuser causes the pressure on the blade surface to fluctuate violently，the passage vortex and throat vortex migrate and accumulate laterally in the diffuser channel，which aggravate the aerodynamic instability of the compressor.