Effects of reynolds number on internal flow field of centrifugal compressor with the volute

The flow field of a whole flow passage centrifugal compressor with its volute was simulated numerically to investigate the changing trends of the performance at different Re. Effects of Re on the internal flow were analyzed in detail. The results show that, compared with Re=1.4×10⁵, the peak efficiencies of the compressor are down 4.5% with Re=5.7×10⁴ and 8.5% with Re=1.3×10⁴, respectively. The highest efficiency point is near 10% blade span in all working conditions. Due to the influence of the volute, efficiency and working range of the compressor are lower than the calculation results of single passage. In the case of low Re, the air flow ability to resist the adverse pressure gradient decreases rapidly. The leakage flow at one blade tip clearance would bypass the leading edge or blade tip of its adjacent blade with the flow developing downstream. More serious secondary flow is caused by increasing the reduced static pressure gradient on the blade surface along radial direction. The performance of the compressor significantly deteriorates owing to increasing shock intensity, boundary layer thickness and wake width.