Control of Inner Flow Field Inside A Transonic Centrifugal Compressor with Splitter Through Chordwise Sweep

The strategy of sweep design should be based on the inner flow field of the compressor. In this paper, a transonic centrifugal compressor within the splitter is discussed in detail, and both forward sweep and backward sweep are studied with numerical simulation for optimization. Splitter introduces extra leakage and it's worth noting that the high-entropy region is shifted from the suction side of the main blade to the suction side of the splitter. Different from the transonic axial rotor, the leakage of the main blade mainly occurs after the passage shock and will be mixed with the leakage of the splitter in the suction side of the splitter. Therefore, the flow control on the middle and rare part of the compressor is more essential for the performance of the stage. In this regard, the backward sweep of the main blade exhibits a good effect by reducing the mixing loss of secondary leakage. Due to the redistribution of the airflow, the mainstream velocity in the tip area is accelerated in the forepart and reduced in the rare part, the aerodynamic loss in the high-entropy zone is then improved, and the flow capacity of the compressor is also increased. The best performance is achieved by an 8° backward sweep for the centrifugal compressor in this work, the pressure ratio is increased by 2.84% and isentropic efficiency is increased by 1.40%, compared to the prototype.