Effect of shroud end wall structure on tip leakage flow in highly loaded helium compressor rotor

In this paper a novel casing treatment structure i.e. leading edge suspended groove shroud end wall structure is proposed in order to reduce the tip clearance losses in highly loaded helium compressor. The highly loaded design method of helium compressor can effectively resolve the problem of helium compression in high temperature gas cooled reactor (HTGR) plants. However, smaller blade height and increase in blade loading cause higher tip clearance leakage losses. The result shows that the leading edge suspended groove shroud structure in highly loaded helium compressor rotor effectively controls the formation of the tip clearance leakage flow and reduces the tip clearance leakage loss. 30° groove slope minimizes the total clearance losses close to blade tip. Moreover, It increases the efficiency of the highly loaded helium compressor by 0.4% at 1 mm tip clearance gap.