Film cooling performance under plasma aerodynamic actuation and spoiler ribs of an internal cooling channel based on Suzen model

Abstract

In this paper, a plasma actuator (PA), treated by the Suzen model, is introduced into film cooling, and four rows of rectangular ribs are employed in internal cooling. Combined action and individual action of film cooling and internal cooling are then investigated at four blowing ratios (M = 0.25; 0.5; 0.75; 1.0). Results show that (no PA, no ribs) the coolant is ejected from the film hole in a spiral form under the action of internal crossflow, and its distributions are inclined to crossflow direction. When the plasma actuator is opened (no ribs), the strength and scale of the counter-rotating vortex pairs are weakened, and the motion of coolant is accelerated, the average cooling effectiveness shows an increase of 82.4% (M = 0.25), 98.9% (M = 0.5), 33.4% (M = 0.75) and a decrease of 2.1% (M = 1.0), the spanwise cooling effectiveness is raised by 57.3–143.3% for each streamwise position, the flow coefficient is lowered by 1.8–3.2%. Ribs (no PA) interfere with the coolant flow in the internal channel, reducing the rotation degree and exit momentum of the coolant, and greatly eliminate the uneven distribution of coolant along the spanwise direction, resulting in an enhancement of 50.4–162.8% in the spanwise cooling effectiveness and of 59.2% (M = 0.25) and 79.5% (M = 0.5) in average film cooling effectiveness. The effect of combined action (PA plus ribs) is lower than those effects of individual factors, and wall average film cooling effectiveness with PA and ribs exhibits a 62.4% (M = 0.25) and 49.4% (M = 0.5) higher to PA off a case (no PA, no ribs); however, a local or global heat transfer deterioration appears at M = 0.75 and 1.0.