Experimental investigation of aerodynamic interaction between tip leakage flow and spontaneous tip injection flow using 2D-PIV

This paper aims to investigate the flow field characteristics of tip leakage flow in a linear cascade with single-hole spontaneous tip injection (STI) introduced as a passive control mechanism. A small-scale low-speed wind tunnel test rig was developed and the planar flow field adjacent to the injection hole was measured under different operating conditions using 2D-PIV technique. This paper presented the detailed aerodynamic interaction between the STI and the tip leakage flow (TLF) under the both laminar and turbulent flow conditions in the tip clearance. Based on the measurement results, we found that the maximum suppression effect occurred in the 3 m/s case in the range of test velocity, and the suppression mechanism of spontaneous tip injection on tip leakage flow were illuminated preliminarily. The vortical structure similar to the Karman vortex street (KVS) appearing in the wake of tip injection flow was noticed and discussed briefly in this paper.