Assessment of Large Eddy Simulation Predictive Capability for Compound Angle Round Film Holes

Abstract

Film cooling holes with a compound angle are commonly used on high pressure turbine components in lieu of axial holes to improve effectiveness or as a result of manufacturing constraints. Whereas large eddy simulation (LES) of axial holes is becoming more common place, assessment of LES predictive ability for compound angle hole has been limited. For this study, the selected compound angle round (CAR) hole configuration has a 30 degree injection angle, a 45 degree compound angle, and a density ratio of 1.5. The geometry, flow conditions, and experimental adiabatic effectiveness validation data are from McClintic et al. [28]. The low free stream Mach number of the experiment puts the flow in the incompressible regime. Two LES solvers are evaluated, Fluent and FDL3Di, on structured meshes with a range of blowing ratios simulated for plenum, inline coolant crossflow, and counter coolant crossflow feed holes. When a steady inlet profile is used for the main flow, LES agreement with the data is poor. The inclusion of a resolved turbulent boundary layer significantly improves the predictive quality for both solvers; consequently, resolved inflow turbulence is a required aspect for CAR hole LES. The remaining differences between the simulations and IR data are partly attributed to the steady coolant inlet profiles used for the counter and inline cross feeds.