Effects of trench configuration on the film cooling effectiveness of a fan-shaped hole

In this study, the effects of three trench configurations - the height, the distance from the hole exit to the downstream sidewall, and the radius of the curvature of the downstream sidewall - on the film cooling effectiveness of fan-shaped holes were experimentally investigated. The film cooling effectiveness was measured using pressure sensitive paint (PSP), and the experiment was conducted with blowing ratios of 1.0, 1.5, 2.0, and 2.5, and density ratios of 1.0 and 2.0. The results demonstrated that the film cooling effectiveness inside the trench was generally higher for cases with larger trench heights, smaller distances between the hole exit and downstream sidewall, and smaller radii of curvature. The smaller distances between the hole exit and downstream sidewall showed higher film cooling effectiveness outside the trench. The higher density ratio cases resulted in higher overall film cooling effectiveness. In general, the film cooling effectiveness for fan-shaped holes with a trench was higher than that without a trench. However, a lower trench resulted in lower film cooling effectiveness. (c) 2021 Elsevier Ltd. All rights reserved.