Study on the impact of fouling on axial compressor stage

Mechanistic research on the fouling of the compressor is necessary to delay the deterioration caused by fouling during long-term operation, and to explore methods that will lower compressor component deterioration, thereby improving the overall performance. The effects of fouling on the performance of an axial compressor stage were investigated numerically. As a representative of the realistic compressor stages, the NASA Stage 35 was considered to perform a numerical investigation by means of a commercial computational fluid dynamic code. The numerical model was validated by comparing with the experimental data available from literatures. The computed performance maps and exit parameter distributions showed a good agreement with experimental data. The model was then used to simulate the effect of fouling on compressor stage by various fouling configurations including added thickness and surface roughness levels. The mechanism of the compressor deterioration due to fouling was discussed in detail. As a result, despite the contribution of added thickness on the work capacity, it substantially narrowed the table operating ranges substantially, causing a greater effect on the overall compressor performance. The influence of roughness applied in the rotor is similar to that in the whole stage, including the drop in mass flow rate at choked and near stall point, pressure ratio, and efficiency, whereas, compressor performance slightly decreases in the stator. When the surface roughness is equal to 50 μm, the drop in mass flow rate under a low Reynolds number is less than that under normal conditions, with little influence on the stable operating range.