Experimental and numerical investigations are carried out to analyze the effect of tangential coolant injection on overall film cooling performance in a cylindrical test section simulating a high curvature surface. Experiments are conducted using hot air as core gas and nitrogen gas as coolant injected through cylindrical holes inclined at 30-degrees to the core gas flow. A three-dimensional multi-species numerical model is formulated using the finite volume formulation and is validated using the obtained experimental data. Simulation results indicate that an optimum blowing ratio exists for which the effectiveness is maximum. The conjugate effectiveness is observed to be higher than adiabatic effectiveness values except in the vicinity of injection owing to the wall conduction effects. Numerical analysis performed with an annular slot placed at the exit of the coolant holes showed an increase in the effectiveness by 21 % compared to the base hole. It is expected that the knowledge acquired in this study has the potential to support new ideas in gas turbine film cooling techniques such as turbine casing film cooling.

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