The Influence of Discretization Scheme on Large Eddy Simulations of Discrete Film Cooling Holes

Large Eddy Simulations were performed on a simple angle cylindrical film cooling hole with a 35° inclination angle and a length-to-diameter ratio of 3.5. A density ratio of 1.25 and velocity ratio of 0.80 was employed, yielding a mass flux ratio of 1.0 and momentum flux ratio of 0.80. Three different discretization schemes were used in otherwise identical simulations: bounded central differencing, pure second-order upwind, and pure secondorder central differencing. The results of these three cases are compared with experimental data from open literature studies in terms of surface adiabatic effectiveness, mean temperature and velocity fields, and unsteady turbulence characteristics. The pure central differencing scheme was found to perform the best in this film cooling scenario, while the upwind scheme also preformed well. The bounded central scheme compared poorly with the experimental data and the other two schemes. The present investigation was made in an attempt to further explore the abilities of Large Eddy Simulations to resolve the complex flow structure arising from the injection of a film cooling jet into a turbine hot gas path.