Effect of hybrid leading edge sweep on the aerodynamic performance of small scale transonic centrifugal compressor

Four transonic compressors with hybrid swept blades were designed by a fully three-dimensional CFD technique, and numerical simulation was carried out to study the influence of hybrid swept leading edge on the flow field of compressors. Result shows that utilication of hybrid forward sweep blades improves flow capacity, extends stall margin, and reduces flow instability, bringing significant improvement of the compressor operation margin. On the contrary, the surge margin is reduced with the hybrid backward sweep blades. For the internal complex flow field, it is found that shock wave decreases significantly near the leading edge and shock wave moves to the upstream of channel by using the hybrid forward sweep blades, while shock wave is strengthened and shock loss increases due to the employment of hybrid backward sweep blades. Analyzing the internal flow of compressor channel shows that the distribution of low energy flow is improved for the splitter through both of swept compressor, in which the effect of forward sweep is much better. In general, the effect of hybrid leading edge sweep on the secondary flow concentrates on the blade leading edge, and there is small influence on the exit of impeller. Usage of hybrid forward sweep blades has an obvious effect on improving flow capacity, operating margin and internal flow.