Computational study of pressure side film cooling—effect of density ratio with combination of holes

Abstract

Film cooling is a proven cooling technique for gas turbine blades. The temperature distribution and flow phenomena vary with the suction and pressure sides. A computational investigation is carried out to understand the film cooling effectiveness and flow phenomenon on pressure side of a gas turbine aerofoil. A specific turbine blade profile is considered with combination of cylindrical and shaped holes in staggered fashion, oriented at different angles. Computations are carried out using the k-ϵ Realizable model available in the commercial code FLUENT 6.3. Meshing of the present model is done by using GAMBIT. The parameter variation considered for the present study is the blowing ratio (0.5–1.25) with an interval of 0.25 and three different density ratios (DR) 1.25, 1.5 and 2. The film cooling performance is discussed with effectiveness distribution on the interface wall. It is inferred that the film cooling performance enhances with increasing density ratio values. Also the optimum value of blowing ratio lies close to 0.75 for higher density ratio values of 2.