Film cooling of cylindrical holes on turbine blade suction side near leading edge

Abstract

The influences of blowing ratio, rotational speed, Reynolds number, and injection angle on film cooling were experimentally studied on turbine blade suction side near leading edge. One row of round holes is located at streamwise location of 13.5% on suction side. Three injection angles, 30°, 45°, and 60°, were tested. Investigations were conducted with three rotational speeds, 300 rpm, 400 rpm, and 500 rpm with blowing ratio varying from 0.5 to 3.0. Reynolds numbers corresponding to rotational speeds are 20,300, 27,200, and 33,800, respectively. Steady-state Thermochromic Liquid Crystal thermography was adopted to measure the adiabatic film cooling effectiveness. The pressure distributions and the second flow of the whole fluid domain were numerical simulated. Results showed that the blade mid-span has the best film coverage. Film cooling effectiveness descends with the increasing blowing ratio. Rotation can deflect the film trajectories toward the tip of the blade. The corresponding Reynolds number increases with the increase of rotational speed, which improves the film cooling performance. The coolant ejects with a smaller injection angle and a smaller blowing ratio can produce weaker inward film defections and so a better film coverage.