Experimental and Computational Investigations of a Comb-Like Film-Cooling Scheme

Abstract

Film-cooling hole-geometry research needs a better understanding in the mechanism of film cooling effectiveness, which was recently shown to depend rather strongly on the counter-rotating vortex pair (CRVP); in this work, a mechanism of the film-cooling heat transfer is proposed. Its mainstream entrainment was aimed to be eliminated by developing a new scheme named comb scheme, which was intended to move CRVP away from mainstream-coolant interface, rather than suppressing CRVP itself. It is investigated experimentally and numerically in this work. The transient thermochromic liquid crystal technique was used in the experimental work, while the Reynolds-averaged Navier-Stokes equations coupled with a realizable κ-ε turbulence model was used to simulate the flow numerically. The results were assessed against open published results hence demonstrating the so called ‘ideal’ performance (film cooling effectiveness = 1) of the new scheme, but with practical structural integrity. The geometric parameter analysis showed that the visualized strong CRVP, where intensity is more than 20, is trapped in the blind slot, hence its impact on mainstream-coolant interface is dropped to approximately 3, and mainstream entrainment is eliminated. It confirms the success of the comb scheme in achieving the high performance of the film-cooling heat transfer mechanism.

Notes

1 Also named Case A, as a selected case with typical high performance.

2 Also named Case B, as a selected case with typical low performance.

Additional information

Funding

Open Access funding provided by the Qatar National Library.

Notes on contributors

Hao-Ming Li

Hao Ming Li is a Ph.D. candidate at Energy and Heat Transfer Laboratory in University Concordia, Montreal, Canada. The present article is a part of his Ph.D. thesis. His main interests are on the film cooling heat transfer, in both numerical and experimental research works.

Wahid Ghaly

Wahid Ghaly is a Professor at Concordia University, Montreal, Canada. He received his Ph.D. degree from the Aeronautics and Astronautics Department at MIT, Cambridge. He has over 30 years of research experience in the field of turbine aerodynamic design systems and related research.

Ibrahim Hassan

Ibrahim Hassan is a Professor at Texas A&M University, at their branch in Qatar. Before, he was a Professor at Concordia University, Montreal, Canada. He has over twenty years of research experience in the field of heat transfer and energy systems. He is a Fellow of ASME.