Research On Influence Of Gap Of Rotor And Stator On Stage Performance Of Micro Centrifugal Compressor

Micro centrifugal compressor has been widely applied for military and civil use as its highsingle-stage pressure ratio, simple structure, and small axial length. It is significant for increasingstage performance of micro centrifugal compressor to understand the internal flow in thecompressor. So, in this paper the law of influence of gap of rotor and stator on stage performanceof micro centrifugal compressor is researching by numerical simulation, mainly in the followingaspects:1. Analysis for the mechanism and structure of internal flow in centrifugal compressor iscarried out and the source of loss is found. The influence and cause of shock wave, leakage vortex,passage vortex,“jet-wake” and non-uniform distribution of the parameters at inlet of vaned diffuseron compressor are researched.2. A comparison on performance and flow structure of the impeller between the case of theimpeller with tow kinds of vaneless diffusers and vaned diffuser. The performance is not muchdifferent between the impeller with the tow diffusers, the pressure tario, efficiency and ability ofacting of the impeller are decreased and the separation vortex moves to the exite of the impeller.The law of influence of vaned diffuser on the distribution of parameters at exit of impeller isfounded, the diffuser can affect a range of20%impeller chord from impeller trailing edge onimpeller performance.3. The law of change of the internal flow in the compressor at different relative positionbetween rotor and stator is founded by unsteady simulation. The influence of cyclical non-uniformdistribution of the parameters at inlet of vaned diffuser on impeller by unsteady simulation isresearched.4. Analysis for the mechanism of internal flow in gap between rotor and stator is studied. Theparameters of the impeller and stage are compared between the different gaps. The flow structureand parameters of three different cases are analysed. The law of the influence of gap between rotorand stator on centrifugal compressor is founded. There is a best gap between rotor and stator for thecentrifugal compressor, in this paper, when the maximum diameter and geometry parameters at theoutlet of the diffuser are determined, the best gap is r3/r2=1.08.