Secondary Flow Decay Downstream of Turbine Inlet Guide Vane With End-Wall Contouring

The secondary flows development downstream of a turbine stator blade with non-symmetric endwall contours is measured and analyzed. Measurements are carried out in a subsonic linear cascade with a large test section. The measurements are carried out using micro-pneumatic five hole probes which allow a detailed description of the vortical structures. The effect of secondary flows on the blade load is discussed. The passage vortices are found to collide and produce two pairs of counter-rotating vortices. The collision is caused by the mutual influence of the endwall contours and the pressure distribution on the blade. The measurements in 13 planes downstream of the trailing edge also show the presence of an extra vortex which appears because of sudden channel expansion. The 13 measurement planes orthogonal to the mean flow allow a detailed description of the secondary flow decay. The large flow distortion in terms of pitch and yaw angles is analyzed and discussed.