Numerical study on the impact of fouling on an axial compressor middle stages

Three-dimensional numerical simulation software CFX was used in an investigation of two-middle-stage of a heavy-duty gas-turbine compressor. By altering roughness of endwall and blades as well as thickness of blades to simulate the varying degrees of fouling in the compressor, the performance and flow filed characteristics of the two stages axial compressor were analyzed. By taking different fouling settings, the interaction of fouling on the former and latter rotor was discussed. As a result, fouling on either former or latter rotor will aggravate the corner separation in the rotor passage, which also leads to the compressor performance decreasing. The influence of increasing roughness is significantly greater than thickening, and the impact of the former rotor is bigger than the latter; Fouling on either the former or latter rotor itself has little influence on the other rotor's isentropic efficiency, and the impact of thickening is bigger than increasing roughness. The interaction of fouling on the former and latter rotor reflects on the total pressure ratio, which is related to the degree of blockage caused by fouling.