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.
