The pressure ratio required for a turbocharger centrifugal compressor increases with internal combustion engine power density. High pressure ratio causes a transonic flow field at the impeller inducer. Transonic flow narrows the stable flow range and de-teriorates stage efficiency. In this work, an advanced high pressure ratio transonic compressor was designed. The experimental results show that the maximum pressure ratio of this turbocharger is about 4.2, the maximum efficiency is above 80% and the stable flow range at the designed rotating speed is up to 34%. A turbocharger with this transonic compressor has been applied to some vehicle research actually, and improved power density by 40%.
ZHENG XinQian, ZHANG YangJun & YANG MingYang State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China
All components of a turbocharger compressor are axisymmetric except for the spiral-shaped,gas-collecting overhung volute.In this paper,a novel experimental method to evaluate the impact of the volute's asymmetry on centrifugal compressor performance is proposed and applied to a high pressure-ratio turbocharger compressor.This method can isolate the impact of the volute's asymmetry on the compressor performance for the first time.Experiments prove the considerable impact of the volute's asymmetry on the compressor performance,especially the stability and efficiency.The impact of the volute's asymmetry on compressor stability correlates with rotational speed and thus with the pressure ratio,constricting the stable flow range by up to 47 percent and decreasing the maximum efficiency by 4.8 percent at the design speed.The results provide evidence to exploit the potential of intrinsic non-axisymmetric flow induced by asymmetric volute to improve the performance of turbocharger compressor with a high pressure ratio.
LIN YunZHENG XinQianJIN LeiTAMAKI HideakiKAWAKUBO Tomoki
Thermal fatigue (TF) is one of the most important factors that influence turbine's life.This paper establishes a 3D solid-fluid coupling model for a steady temperature analysis of a high-pressure turbine nozzle at different turbine inlet gas total temperatures (TIGTTs).The temperature analysis supplies the temperature load for subsequent 3D finite element analysis to obtain the strain values.Following this,the prediction of the TF life is made on the basis of equivalent strain range.The results show that the strain increases with TIGTT,and the predicted TF life decreases correspondingly.This life prediction was confirmed by one TF test.
