Experimental Study of Tip Clearance Effects on Performance and Flow Field of a Centrifugal Compressor

In this paper, the experiment is carried out to study the effects of tip clearance on overall performance and flow field of a centrifugal compressor, and the operating tip clearance sizes of the impeller are measured by the Non-contact optical fiber displacement sensors. The results shows that, the operating tip clearance sizes fluctuate as time, the averaged operating tip clearance is smaller than the cold one. The pressure ratio and efficiency of centrifugal compressor decrease as the tip clearance increases, and the effects are more obvious with higher rotation speed. At the same time, the analysis of flow field indicates that, the influencing zone of tip clearance flow move upstream as the flow rate decreases. An increased tip clearance expands the influencing zone of tip clearance flow and increases the pressure loss.