Performance investigation of sCO2 compressors under various splitter length and circumferential positions for advanced power generation

The sCO2 Brayton cycle is recognized as a highly promising advanced power cycle, garnering significant attention for its future development and applications. The centrifugal compressor serves as the core component of the supercritical carbon dioxide Brayton cycle. As a critical structural element of the centrifugal compressor, the splitter blade plays a vital role in influencing compressor performance. However, the improved length and circumferential position of the sCO2 compressor's splitter blade remain areas for further exploration. This paper investigates the best circumferential position corresponding to the improved splitter blade length to achieve maximum performance of the sCO2 compressor impeller. It also explains the improvement in impeller efficiency from the perspective of loss mechanisms. Additionally, the study examines the interaction between the structural parameters of the splitter blade. CFD results demonstrate that the length and circumferential position of the splitter blade independently affect impeller performance. The three-dimensional loss analysis shows that, under design conditions, the improved length coefficient and circumferential position coefficient for the splitter blade are both 0.5. The improvement in impeller performance is attributed to the combined effect of flow losses in mainly three regions. Changes in the length and circumferential position of the splitter blade alter the total loss, impacting impeller performance. Furthermore, the comparison of flow field in sCO2 compressors is made between the improved compressor and the original compressor. Presented results in this paper shed light on how modifications in flow dynamics contribute to the enhancement of impeller performance.