The Effect of Vortex Shedding in Film-Cooling Processes

Abstract

Film cooling using coolant jets is effective for increasing the cooling effectiveness of turbines. In the present study, large eddy simulation was employed for predicting small-scale vortices in the film-cooling process with different blowing ratios (BRs). The counter-rotating vortex pair (CRVP) was compared with the hairpin vortex, and results indicated the CRVP was the cross section of hairpin vortex. The results of a spectral analysis indicated a high correlation between the shedding period of the CRVP and the film-cooling effectiveness, and the dominant frequencies of the temperature and vorticity spectra were both identical to the shedding frequency of the CRVP when BR is less than 0.75. Furthermore, a higher shedding frequency of CRVP will suck the hot cross-flow into the core region more frequently, which will lead to a worse film-cooling effectiveness.

Disclosure statement

We declare that we have no financial or personal relationships with other people or organizations that can inappropriately influence our work. There is no professional or other personal interest of any nature in any product, service, and/or company that could be construed as influencing the review of the manuscript.

Additional information

Funding

The authors acknowledge the financial grants from the National Project No. 6140206040301 and the Special Project for Important Fields in the 13th Five-Year Plan from Sun Yat-sen University (No. 17lgjc41) for supporting the present work.

Notes on contributors

Zhi-ya Chen

Zhi-ya Chen is a PhD student at the Department of Applied Mechanics and Engineering, Sun Yat-sen University. He earned his Bachelor in Sun Yat-sen University.

Jie-min Zhan

Jie-min Zhan is a full professor of Sun Yat-Sen University. He is a coeditor of Engineering Applications of Computational Fluid Mechanics. His research areas are fluid dynamics, thermodynamics and hydrodynamics. He has published more than 100 journal papers.

Chi-wai Li

Chi-wai Li is a full professor of the Hong Kong Polytechnic University. His research areas are computational fluid dynamics, coastal and environmental hydraulics. He has published more than 100 journal papers. He is an associate editor of the Journal of Hydro-environment Research and the journal Engineering Applications of Computational Fluid Mechanics.

Wen-qing Hu

Wen-qing Hu received his PhD from Sun Yat-Sen University majored in Fluid Mechanics. His research interests are experimental hydrodynamics and computational fluid dynamics.

Ye-jun Gong

Ye-jun Gong received her PhD from Michigan Technological University and majored in Computational Science and Engineering. Her research interests are computational fluid dynamics with application in turbulent flow, multiphase flow and bio-mimetic fluid dynamics.