Investigations of modified cooling hole injection angle configurations for improved trench film cooling performance

Abstract This study aims to evaluate the film-cooling performance of trench film cooling with a modified cooling hole injection angle configuration. Five different film hole injection angle configurations viz., forward injection 30°, forward injection 60°, perpendicular injection 90°, backward injection 60°, and backward injection 30° were tested for their performance through Computational fluid dynamic simulation. All the configurations were tested on a trench with a fixed length of 2 times and depth of 0.75 times the film hole diameter. The investigation was conducted at three blowing ratios of 0.4, 1.2, and 2.0. The experimental results of trench film cooling effectiveness with a backward injection of 30° show a close agreement with the computational data. The backward injection 30° film hole configuration has improved the spatially averaged film cooling effectiveness on the trench test surface by 29.41 % at a blowing ratio of 0.4, 30.65 % at a blowing ratio of 1.2, and 47.18 % at a blowing ratio of 2.0.