Experimental and numerical studies on film cooling of a corrugated surface

In this paper the procedure to arrive at a suitable film cooling configuration of an aero engine afterburner liner is discussed. Numerical studies are carried out to select (i) locations of film cooling holes, axial pitch, transverse pitch and hole size on corrugated liner. Numerical studies are extended to investigate the influence of various operating parameters such as mainstream Reynolds number, blowing ratio and density. In the numerical study mainstream Reynolds number is varied from 10 x 10(3) to 4.5 x 10(5), blowing ratio is varied from 0.8 to 3 and density ratio is varied from 1.8 to 5. Effect of coolant injection angle is also studied by varying injection from 45 degrees to 90 degrees. Experimental studies are conducted on the corrugated surface to validate the computational methodology. The parameters considered in the experimental study are: the mainstream Reynolds number of 2 x 105, blowing ratio of 1.8 and density ratio of 0.91. It is found from the current study that the film cooling behavior on a corrugated surface is different from that on flat surfaces. Film cooling effectiveness increases with increase in mainstream Reynolds number upto 3.79 x 10(5) and thereafter it decreases slightly. Blowing ratio and density ratio have significant impact on the film cooling. Film cooling effectiveness increases with the increase in the blowing ratio even at very high blowing ratios. It is also observed that the film cooling effectiveness drastically decreases as injection angle is increased from 45 degrees to 90 degrees. (C) 2016 Elsevier Ltd. All rights reserved.