Investigation on the Highly Loaded Helium Compressor Based on Helium Thermophysical Properties: Part A — The Design of Highly Loaded Axial Helium Compressor

Helium is hard to be compressed with the traditional way of air compression because of thermophysical properties differences between helium and air, which would result in helium compressor being of much more stages and shorter blades. In this paper, based on the flowing features of helium, that is, the higher sound speed, the lower Mach number etc. which are also due to the specific thermophysical properties of helium, the design method of a highly loaded helium compressor is investigated in detail. The relationships between the highly loaded helium compressor flow coefficient, load coefficient, reaction degree and its efficiency and pressure ratio are systematically discussed. Then, to meet the higher efficiency and reliability requirements, unequal spanwise work distribution technique is implemented. The results indicate that a 16 stages helium compressor of a 300MW HTGR can be reduced to a 3 stages compressor by the highly loaded design method proposed in this paper, under the condition of the same tip tangential velocity. The polytropic efficiency is 90%, which is higher than that of the previous 16 stages compressor.