Analysis of the low-speed similarity design principle for a compressor airfoil

Some theoretical analyses have been done for the high-to-low blade airfoil similarity designs. The critical factors for the high-to-low transformations were clarified, and some design rules were also proposed.Based on the theoretical analyses, a high-to-low design case of a typical high subsonic compressor airfoil used in a rear stage of a high pressure compressor was carried out. The results showed that, by using the similar normalized blade surface velocity distribution to that in the high speed case to design the low speed airfoil, the low speed blade can achievethe similar blade characteristics to that of the high speed blade. Particularly, the characteristics curves of the inlet-ow-angle/total-pressure-loss for the low and high speed cases are nearly the same from the design condition to the near stall condition. the inflow angle-total pressure loss.