Method and numerical simulation for evaluating the effects of water film on the performance of low-speed axial compressor

Abstract

Numerical simulations for a low-speed axial compressor under water ingestion are performed to evaluate the aerodynamic performance degradation due to the formation of water film. The water film thickness on a blade surface is calculated by a self-compiled program developed by the authors. In addition, the blade surface is divided into several regions, which can be roughened separately, to elucidate the characteristics of the nonuniform water film. The equivalent sand roughness corresponding to the root-mean-square water film thickness are specified for the blade surface to simulate the aerodynamic losses of the blade row caused by water deposition. The results show that the water film thickness is positively correlated with the water content, and negatively correlated with the compressor outlet pressure. The overall compression performance presents a downtrend after water ingestion. When the water content increased from 0.37% to 4.02%, the compression efficiency deteriorated by 1%–3% compared with the dry condition. The distribution of the static pressure coefficient on the blade surface is also changed, wherein the deviation degree at the tip region is greater than that at the hub region. Unfortunately, considering the limitations of the current water film models and computational methods, the water film formed on the tip region cannot be simulated. Therefore, the calculated results near the stall point are different from the experimental results. However, rough surface treatment can still be considered as a feasible method for evaluating the effects of water film on compressor performance.