Experimental study on expanding the efficient operating range of two-stage series high-speed centrifugal air compressors

The high-speed centrifugal compressor stands out as a vital component of the fuel cell system, accounting for the greatest power consumption among auxiliary systems. Concurrently, the efficient operating range of the centrifugal compressor also affects the operating range of the battery stack. Therefore, in the fuel cell system, it is not only necessary to improve the efficiency of the centrifugal compressor, but also to broaden its efficient operating range. In this study, a high-speed two-stage series centrifugal (HTSC) air compressor is chosen as the gas supply component for a 100kW proton exchange membrane fuel cell (PEMFC) system. Additionally, the efficiency and efficient operating range of the HTSC air compressor are improved by optimizing the multi-objective parameters of the centrifugal impeller. In the optimization model, the specific diameter is modified to suit the design of the HTSC air compressor. This optimization work is proved to be effective by the experimental data of the baseline and optimized HTSC air compressor. The design point efficiency of the optimized HTSC air compressor is improved to 87.06% from 81.19%. The stable operating range at pressure ratio 2.5 of the optimized compressor is broadened by 55% and its efficient operating range (efficiency > 0.75) is broadened by 48%.