Numerical Simulation on Fluid Flow and Heat Transfer of Film Cooling With Backward Injection

Film cooling has been used in gas turbine engines for many years. In film cooling, the relatively cold air blankets the blade surface so that heat transfer between the hot working gas flow and blades is reduced. The main issues related to film cooling are its poor coverage, aerodynamic loss, and increase of heat transfer coefficient due to strong mixing. To overcome these problems, film cooling with backward injection is investigated in this paper, while the coolant air in the existing designs is injected with a forward angle in the mainstream direction. The focus of this paper is on the simple cylindrical hole with different blowing ratios and angles. Numerical simulation is carried out to explore the detailed flow structure and heat transfer behavior of the backward cooling scheme, and its performance is compared with that of the existing design.