Numerical Simulation Of Flow Distortion Of Centrifugal Compressor With Low Specific Speed

Recent years the fossil energy shortage and environmental situation are becoming increasingly serious,our country is facing the challenge of energy shortage and environment pollution.The implementation of dual-integration certification policy puts forward new requirements for fuel vehicles and new energy vehicles at the same time,Electric centrifugal compressor must be used for fuel vehicles to continue to reduce emissions.The development of new energy technologies for fuel cells requires a pressurized intake.Routine use of centrifugal compressor speed need to be as high as 100000 turn above,due to the motor speed is far lower than this level,the ultrahigh speed of the motor due to the high cost is difficult to large-scale application in the car,research is suitable for ordinary motor driven low specific speed centrifugal compressor is imminent.This article according to the volute of low specific speed compressor flow field caused by distortion problem,aims to study distortion caused by volute of centrifugal compressor.A mathematical model is established based on the circumferential distortion caused by volute.The high pressure ratio and low pressure ratio of three kinds of distortion amplitude are calculated respectively.Then draw their performance curves.The influence of distortion amplitude on compressor performance is investigated..The pressure in the impeller passage,different cross section distortion amplitude and entropy are analyzed respectively in this paper,it is concluded that the circumferential pressure fluctuations caused by spiral upward propagation law within the compressor,discovered the distortion phenomenon of the increase of amplitude in the impeller passage,and from the splitter blade structure and pressure changes two aspects has carried on the explanation.It is found that the mass flow and pressure of the impeller exit are not very consistent with the slope of the change in the circumferential direction.The phase difference between flow and pressure is affected by the speed and distortion amplitude of the compressor.In this paper,the periodic variation of the flow of centrifugal compressor fluid in impeller is analyzed by means of unsteady simulation.Come in with outlet pressure distortion the actual flow passage reciprocating flow process of vortex,fluid energy dissipation,and the unsteady simulation of impeller channel and Mach number change has a great association with negative pressure areas in the impeller channel.