Experimental Investigation of Net Heat Flux Reduction at Combustion Temperatures

The present work examines film cooling on a flat plate surface with a freestream temperature between 1430K and 1600K and a coolant to freestream density ratio of approximately two. Since the objective of film cooling is to reduce heat flux to a surface, Net Heat Flux Reduction (NHFR) is used to quantify film cooling performance. It is first demonstrated that non-dimensional matching can be used to scale NHFR between freestream temperature conditions of 1490K and 1600K. Next, the NHFR of a single row of cylindrical holes, fan-shaped holes, holes embedded in a trench, and a slot are compared at a blowing ratio of unity. Finally, the NHFR of five rows of cylindrical holes, holes embedded in trenches, and slots are compared to show the effect of a build-up of coolant near the wall.