The Effect of an Upstream Dune-Shaped Shells on Forward and Backward Injection Hole Film Cooling

Abstract

This article presents the numerical results of a new film cooling design that combines the backward injection hole with Barchan-dune-shaped shells (BH-BDS).The performance of this novel design in improving the film cooling effectiveness is compared to other configurations, forward injection hole (FH), backward injection hole (BH), and the configuration that combines the forward injection with Barchan-dune-shaped shells (FH-BDS). Three blowing ratios are considered in this article, M = 0.5, 1.0, and 1.5. The air coolant was injected through holes inclined at 35 and 155 deg for forward and backward cases, respectively. The lateral-averaged film cooling effectiveness and the distribution of adiabatic film cooling efficiency are studied using commercial software ansys-cfx. Three turbulence models, including the k–ω shear stress transport model, standard k–ε, and renormalization group theory (RNG) k–ε are examined in this investigation. The RNG k–ε model is adopted for the present simulation. The main result of this study reveals that the presence of upstream dune-shaped shells with backward hole yield a better film cooling effectiveness especially at higher blowing ratios (M ≥ 1). At M = 1.5, the FH-BDS and BH-BS cases provide an improvement in the area weighted average film cooling approximately about 24.79% and 10.56%, respectively. The BH-BDS design reduces the pressure loss as compared to BH.