Investigation of film cooling effectiveness and heat transfer coefficient for rectangular holes with two rows

摘要

Purpose - The purpose of this paper is to investigate the film cooling effectiveness and heat transfer coefficient in a flat plate with two rows ofrnrectangular injection holes.rnDesign/methodology/approach - Experimental and numerical investigation of film cooling effectiveness in a flat plate with two rows which arernrectangular injection holes. The liquid crystal technique has been used for measuring the heat transfer coefficients on the mixture region. Three injectionrnholes in model are in a single row. The holes are rectangular cross section and they are 9 x 6.5 mm. The injection holes are inclined at 30° along thernmainstream direction. The blowing ratios are from 0.5 to 2.0. The experiments and their computational models are established to investigate its effectsrnat the 330 and 340 and 350 K injection temperatures and the different blowing ratios.rnFindings - The results show that the film cooling effectiveness and heat transfer coefficient of a given flat plate surface, both along the mainstreamrnand lateral direction, depend on the optimum selection of parameters. In this study, the highest effectiveness is determined at a blowing ratio of 0.5.rnFurther increasing the ratio results in reverse effect on the film cooling effectiveness.rnOriginality/value - It is the fist time the film cooling effectiveness is compared at the rectangular injection holes with two rows as experimental andrnnumerical.