Computational and experimental Investigations on film cooling with Surface modifications

Abstract

The film cooling is a process where the second low-temperature fluid is injected into the wall surface which is in contact with the hot mainstream flow and this injected fluid creates a thin low-temperature film layer at the intermediate region between the wall surface and mainstream flow.mFilm cooling is a widely used method of cooling for combustion liners, rocket nozzles, thrust chambers, aircraft, and industrial gas turbines. Most of the components of gas turbines are subjected to higher thermal loads and hence effective cooling techniques are required for their continuous operation. Film cooling provides effective protection and can enhance the life cycle of gas turbine components. Improved film cooling methods can pave the way for higher turbine inlet temperature for gas turbines and this, in turn, leads to higher thermal efficiency. The film cooling improvements need to be cost-effective with fewer complications to manufacture. Film cooling with surface modification is a method, where the film cooling holes are embedded within the cut slots framed on the cooling surface with the application of thermal barrier coating. The present film cooling study has been performed on the flat plate model embedded with surface modifications and this flat plate film cooling can be correlated to end wall surfaces of gas turbine components. Different surface-modified film cooling methods were examined from the literature. The trench, ramp, and crater surface-modified film methods were identified for the present investigation. The film cooling parameters for the surface-modified film cooling methods viz., trench, ramp and crater film cooling were identified from the literature. The identified parameters were grouped into two categories viz., fixed parameters and variable parameters. newline