| As the emission regulations have become stricter,the requirement of the turbocharger pressurizing ability has become higher as well as the centrifugal compressor,an important part of the turbocharger.The improvement of the compressor ratio often accompanied by a heat waving,which can shorten the steady work time.What’s more,the high emission temperature can reduce the inlet density,then weaken the supercharging effect.So it is necessary to cool the compressor to ensure the stability and improve the performance of compressor.In this article a high-pressure ratio centrifugal compressor is chosen as the research subject,use the software NUMECA and CFX to carry on numerical simulation.And get a intact characteristic curve to verify the veracity of the model.In allusion to this compressor the cooling structure behind the compressor is designed,the cooling water flow through the structure can take away the heat.The CFX is chosen to simulate the compressor inner flow field and the cooling structure,first calculate the heat dissipationof the compressor then calculate the heat taken away by the cooling water.The heat dissipation of the compressor field under different rotation speed has been calculated,the results are chosen as the initial condition to calculate the temperature,compressor ratio and mass flow of the compressor under heat transfer conditions,then compared with the adiabatic condition.With the increasing rotation speed,the influence becomes obvious.At the highest speed,the diffuser blades temperature can reduce 28.3K,the working stability of the compressor has been improved obviously.In low speed range,because of the low temperature of the compressor,the influence of the cooling structure is weak.After cooling the parameters of the compressor have been improved.By analyzing the flow field after cooling,it shows that the flow field becomes well-distributed,it can expressed as the change of the outlet mass flow and compressor ratio.Both the mass flow and the compressor ratio are improved so as the steady working range,the flow range has expanded 4% and the compressor range has expanded 5%.At the same time,the efficiency has increased,the highest efficiency can reach 84.3%,the densityof the outlet increase 0.5%. |
