Computational Study on the Boundary Layer Suction Effects in the Supersonic Compressor Flow with a Bowed Blade

Flow control methodologies have been widely used to eliminating flow separation and increasing the blade load in axial compressor. Aiming at revealing the flow mechanism of coupled bowed blading and boundary layer suction in a supersonic compressor cascade, a cascade with a diffusion coefficient of 0.62 is numerically presented. First of all, according to the available experimental data, the numerical method was validated; then, different bowed blading effects on flow field in detail were investigated; at last, based on the flow physics of purely bowed blading, the positively bowed blade was coupled with boundary layer suction on blade suction surface, whereas the negatively bowed blade was coupled with endwall suction. For coupled control method, influence mechanism on flow field, especially on the shock structure was revealed, and different aspect ratios of coupled control method were investigated as well. Results showed that the coupled positively bowed blading and suction surface suction can eliminate the flow separation effectively. Compared with that of baseline supersonic cascade, the total pressure loss coefficient of the coupled scheme was reduced by 37.4% at most. At mid-span, the shock moved downstream and the single shock was separated to a dual-shock structure since the positively bowed blading reduced the static pressure of mid-span. The coupled negatively bowed blading and endwall suction also effectively enhanced the performance of cascade by removing the corner separation, with the loss coefficient reduced by as much as 41.9%. However, the suction coefficient of optimal coupled negatively bowed blading scheme reached 10.5%, which is too high for practical use. After coupled control, the 3D shock structure became “C” shaped distribution along spanwise because of the difference in influence mechanism of negatively bowed blading on different spanwise location. Due to the opposite influence effect of positively and negatively bowed blading, the shock structure in the two different schemes of cascades were different and showed opposite variation trends as aspect ratio increased.