Effect of Location and Rotational Reynolds Number on Film Cooling of Rotating Blade Pressure Side

Abstract

The film cooling performance on the pressure side of turbine blades with single-row film holes is experimentally investigated. Three blades with single-row film holes at three locations (x/S = 10%, 29%, and 48%) of the pressure-side are studied at three rotating Reynolds numbers of 3.6 × 105, 5.4 × 105, and 7.2 × 105 (i.e., the rotational speeds of 400 rpm, 600 rpm, and 800 rpm). The pressure-sensitive paint (PSP) technology is used to measure the film cooling distribution at three blowing ratios (BR = 0.50, 1.00, and 1.50). The results indicate that the film cooling performance varies with the location of pressure side. Upstream of the pressure side, the film cooling performance is poor, with the film trajectories deflecting mainly upward. Downstream of the pressure side, the cooling effectiveness is higher, with the film trajectories deflecting upward and downward. The film trajectories closer to the downstream location are longer than those upstream, and are more prone to detach from the wall at higher blowing ratios. Moreover, the cooling performance slightly improves as the rotating Reynolds number increases.