Experimental and numerical investigation on off-design performance of a high-pressure centrifugal compressor in compressed air energy storage system

In order to explore the off-design performance of a high-pressure centrifugal compressor (HPCC) applied in the compressed air energy storage (CAES) system, the author successfully built a high-pressure centrifugal compressor test rig for CAES, whose designed inlet pressure can reach 5.5 MPa, and carried out some experiments on adjustment of inlet guide vanes (AIGVs), adjustment of rotational speed (ARS) and adjustment of inlet pressure (AIP). Firstly, by analyzing the experimental data with the angle of AIGVs varying from - 20 degrees to +50 degrees, it can be concluded that the mass flow range is widened by 41.18 %, the maximum efficiency is increased by 3.28 %, and the maximum pressure ratio can realize a slight increase. Then, the comprehensive performance map of the HPCC with AIGVs is obtained through interpolating the existing experimental data. Subsequently, the comparison between experimental and CFD results has been analyzed. Since the losses in the inlet expansion joint and outlet expansion joint, the aerodynamic performance obtained by experiments is slightly lower than CFD. Afterwards, the experiments on the ARS are carried out by three different speeds, and the change regulation of the performance by ARS is obtained. Lastly, the experiments on the AIP are carried out by seven different inlet pressure, when the inlet pressure of the HPCC is > 50 % of the designed pressure, the results after simulated modeling are very close to the experiment results of the designed pressure. But once the inlet pressure is lower than 50 % of the designed pressure, the further the inlet pressure deviates from the designed pressure 5.5 MPa, the further the performance curve obtained by simulated modeling deviates from the design working condition. In this research, the experimental performance of a high-pressure centrifugal compressor applied in CAES under off-design conditions was obtained for the first time, which is of great significance to the research and development for the CAES system in the future.