Numerical study of the influence of rain ingestion on the flow field of transonic compressor

The rain ingestion flow field of a four-stage transonic compressor is numerically studied using Lagrange particle tracking method. Considering the breakup, collision and evaporation process of raindrop particles, the influence of water content on the characteristics of multiphase flow field and stable working range of compressor is studied, and the transport process of raindrop in multistage environment is discussed. The numerical simulation results show that the raindrop is broken by the aerodynamic shear force in the front stage of the multi-stage compressor. After colliding with the blade, the raindrop moves to the blade tip and converges near the inner wall of the casing under the centrifugal force. The raindrops are broken into smaller droplets at the back stage of the compressor, and the evaporation process occurs after mixing with high temperature air, thus effectively reduce the air temperature at the outlet of the compressor and improve the wet compression efficiency of the compressor. With the increase of water content, the stable working range of the compressor decreases significantly, and the total pressure ratio and wet compression efficiency increase. When water content ingestion accounts for 5% of the design flow, the stable working range is relatively reduced by 75%, at the design flow point the total pressure ratio is increased by 25%, and the wet compression efficiency is increased by 7.4%. Rain ingestion changes the flow angle matching between each blade row of the compressor. Compared with the design condition, the variation amplitude of the flow angle of attack increases with the increase of water content ingestion and number of stages, and the main variation range is concentrated in the upper half of the blade height. This research provide a reference for revealing the mechanism of multistage compressor rain ingestion flow.