The Influence Of Tip Leakage On The Performance Of Compressor

In order to pursue high performance of modern gas turbine, single-stage compressor requires not only a higher pressure ratio and efficiency, but also has good stability. To prevent compressor rotor and casing wall running friction collision, usually left tip clearance on the top of the blade. The exists of tip clearance impact many aspects of the compressor, the tip leakage flow blended with the mainstream will cause flow losses, and lower the compressor efficiency. Meanwhile leakage flow can also cause airflow blockage inside the compressor,resulting in lower pressure ratio, and even lead to rotating stall and surge occurred. Therefore,it is necessary for the analysis of blade tip clearance flow in compressor, to study its characteristics, which has great significance for enhancing the performance of the compressor.In this paper, as NASA transonic compressor Rotor37 for the study, using numerical simulation tools for the tip clearance flow analysis, from the steady and unsteady two angles to explore the characteristics of the blade tip leakage flow. The core content includes the following aspects.1. Conducted steady numerical simulation calculations of single stage compressor and drawn compressor characteristic curve. By calculating the existence of tip clearance and changes in the size of it, analyzed the impact of the tip clearance to the compressor performance, analyzed the changes of the flow field inside the compressor and the influence on compressor stability boundaries when tip clearance increases.2. Conducted unsteady numerical simulation, calculated the unsteady condition of the compressor. Analyzed the starting position of the tip leakage flow; the changes of transient flow field on the tip region in a unsteady fluctuation cycle and analyzed the mechanism and starting mechanism of the unsteady fluctuation based on the results. Through the study of the numerical simulation of the multi-channel model, verified the validity of the numerical simulation of the single-channel model to analysis the unsteady flow fluctuations of the tip clearance flow.3. The spatial structure of the tip leakage flow is analyzed, from two aspects of two-dimensional and three-dimensional to study its structure.