Numerical investigation of the effect of a turbocharger compressor blades angle on its performance

Power increase, efficiency improve and reduce of fuel consumption of internal combustion engines is a great technological interest. For this reason, turbochargers are widely used in the internal combustions engines nowadays. So, studying of the performance of turbochargers is focused in automotive industries. In the present paper, the effect of blades angle of a turbocharger compressor on its performance is studied numerically. First, the impeller geometry and volute geometry of Garrett T25 turbocharger compressor is acquired using 3D scanning, then it is modeled in CFX Ansys software. The results show that the performance of compressor is slightly changed when the blade angle is changed at the layer of hub inlet. On the other hand, the transferred energy to fluid is considerably increased when the blade angle is increased at the shroud. For the mass flow rate of 0.122 kg/s, the efficiency and total pressure ratio are increased up to 1.67 and 1.7 percent respectively when the blade angle is increased 9 degree at the shroud in comparison to the default compressor. The maximum impact on compressor performance is caused due to changing the angle of the outlet of blade. For mass flow rate of 0.124 kg/s, isentropic efficiency and total pressure ratio is increased 1.12 and 3.43 percents respectively when this angle is decreased 9 degree in comparison to the default compressor. Finally, a new impeller was designed in order to have maximum efficiency and maximum total pressure ratio using the acquired results. The results of the final compressor show a shifted of mass flow range in comparison to the main compressor. For the same mass flow rate, The mean values of isentropic efficiency and total pressure ratio of the final compressor are increased 6.52 and 6.65 percents respectively, while the input power is increased 6.19 percent related to the default compressor.