Flow field structure analysis in straight and bowed turbine vanes under cooling air mixture

To deeply understand the effects of different blade bowed angle on flow field structure in air cooled turbine cascade, the cascade flow field was numerically simulated under different air injections and different blade bowed angles at low speed. The development of secondary flow in cascade was analyzed. The physical quantity swirl was used to analyze the vortex system and secondary flow distribution. The results show that the secondary flow gather on the blade surface, endwall and nearby trailing edge and cooling air holes; the counter radial secondary flow on pressure surface was observed with injection from leading edge, this phenomenon became more obvious as the blade bowed angle increasing; with injection from multiple rows of cooling air holes, the limiting streamlines on suction surface showed obvious fluctuant flow, the amplitude of fluctuation increased as the blade bowed angle increasing.