Effects of upstream endwall film cooling on a vane cascade flowfield

Abstract

The effects of film cooling on the endwall region flow and aerodynamic losses are investigated experimentally as the film flow is delivered from the slots in the endwall upstream of a linear vane cascade. Four slots inclined at 30 deg deliver the film jet parallel to the main flow at four blowing ratios between 1.1 and 2.3 and at a temperature ratio of 1.0. The slots are employed in two configurations pitchwise: all four slots open (case 1) and two middle slots open (case 2). The inlet Reynolds number to the cascade is 2.0E+05. Measurements of the blade surface pressure, axial vorticities, yaw angles, and total pressure loss distributions along the cascade are reported with and without (baseline) the film-cooling flow. The results show that the film flow changes the orientations, distributions, and strength of the endwall secondary flows and boundary layer. Case 1 of film cooling provides more mass flux and momentum than case 2 affecting the passage vortex legs. The overall total pressure losses at the cascade exit are always lower for the film-cooling cases than for the baseline. The overall losses are also lower at the low blowing ratios but higher at the high blowing ratios for the film-cooling case 1 than for case 2.