Numerical investigation of the effect of highly loaded design on the tip leakage in helium compressor rotors

The highly loaded design method of helium compressors can effectively solve the compression problem of helium in high-temperature gas-cooled reactors. However, the reduction in blade height and the increase in transverse pressure gradient lead to more leakage flow problems at the tip clearance. This study aims to develop a deeper understanding of the tip leakage flow physics and its influence on the loss mechanism. The tip leakage loss characteristics and loss mechanisms in a highly loaded helium compressor are analyzed by numerical simulation to provide the necessary knowledge for optimizing the blade tip aerothermal design. Five different blades are designed with different loading conditions and analyzed with five different blade tip clearances. The sensitivity of the aerothermal performance on tip clearance scales in the highly loaded helium compressor rotor is also analyzed. Based on the results and analysis, a new loss model is developed, which can be fully utilized to predict the tip clearance loss in highly loaded helium compressors. The deviations between the predicted values and CFD values can be less than 3%.