Numerical Investigation on the Effect of Impeller Trimming on the Performance of a Modified Compressor

Abstract

This study was intended to predict the performance of a modified centrifugal compressor used in turbo charger numerically. In order to increase the performance of the conventional turbocharger compressor’s to boost the pressure in the engine, by the impeller trimming. The compressor impeller was trimmed at the impeller hub and shroud layers, thus generating different trim geometries, and the effect of the trimming on the compressor impeller performance was studied. The flow inside these geometries of a small modified centrifugal compressor with double splitters used as an automotive turbocharger was simulated. Further, the performance of the centrifugal compressor depended on the flow in the impeller and splitters, but the splitters were not continued to the leading edge. If the splitters continued to the leading edge, it would produce sufficient blockage to cause choking at high speed. This research aimed to study and simulate the effect of impeller trimming on the performance of a turbocharger compressor. The simulation was undertaken using CFD analyse on the aerodynamic flow field and to predict performance in terms of pressure ratio, efficiency, mass flow rate and aerodynamic characteristics. According to the results of the simulation, it was observed that the fluid flow into a compressor has been indicated a better understanding. In addition the compressor performance was heavily affected by the impeller modification. Conclusively, it was observed the performance it was greatly affected by the double splitter design and the pressure ratio and air mass flow rate were increased.