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Article

The Evolution of Flow Structures and Coolant Coverage in Double-Row Film Cooling with Upstream Forward Jets and Downstream Backward Jets

College of mechanical and electrical engineering, Hohai University, No. 1 Xiang Road, Nanjing 210098, China
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Author to whom correspondence should be addressed.
Energies 2024, 17(14), 3387; https://doi.org/10.3390/en17143387
Submission received: 8 October 2023 / Revised: 25 December 2023 / Accepted: 6 January 2024 / Published: 10 July 2024
(This article belongs to the Special Issue Improvement of Gas Turbine Cooling Technology for Carbon Neutrality)

Abstract

The spatiotemporal evolution of the flow structures and coolant coverage of double-row film cooling with upstream forward jets and downstream backward jets, having a significant impact on film-cooling performance, is studied using the simplified thermal lattice Boltzmann method (STLBM). Moreover, the effect of the inclination angle of downstream backward jets is considered. The high-performance simulations of film cooling have been conducted by using our verified in-house solver. Results show that special flow structures, such as a sand dune-shaped protrusion, appear in double-row film cooling with upstream forward jets and downstream backward jets, which is mainly because of the blockage effect resulting from the coolant jet with backward injection. The interaction among structures results in the generation of an anti-counterrotating vortex pair (anti-CVP). The anti-CVP with the downwash motion can result in the attachment of coolant to the bottom wall, which promotes the stability and lateral coverage of coolant film. The momentum and heat transport are strengthened as the backward jet is injected into the boundary layer of the mainstream. Although the downstream evolution of the backward jet is not very smooth, its core attaches closely to the bottom wall due to the downwash motion of anti-CVP. Moreover, there is an obvious backflow zone shown in the trailing edge of the downstream backward jet with a large inclination angle. The obvious backflow makes the coolant attach to the bottom wall well. Therefore, the film cooling effectiveness is improved as the inclination angle of the downstream backward jet varies from αdown=135o to αdown=155o, with a constant blowing ratio of BR=0.5. In addition, the fluctuation of the bottom wall’s temperature is weak due to the stable coverage of the coolant layer under αdown=155o. The film-cooling performance with an inclination angle of αdown=155o is the best among all the cases studied in this work. This work provides essential insights into film cooling with backward coolant injection and contributes to obtaining a complete understanding of film cooling with backward coolant injection.
Keywords: spatiotemporal evolution; flow structures; coolant coverage; simplified thermal Boltzmann method; film cooling; forward and backward jets spatiotemporal evolution; flow structures; coolant coverage; simplified thermal Boltzmann method; film cooling; forward and backward jets

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MDPI and ACS Style

Shangguan, Y.; Cao, F. The Evolution of Flow Structures and Coolant Coverage in Double-Row Film Cooling with Upstream Forward Jets and Downstream Backward Jets. Energies 2024, 17, 3387. https://doi.org/10.3390/en17143387

AMA Style

Shangguan Y, Cao F. The Evolution of Flow Structures and Coolant Coverage in Double-Row Film Cooling with Upstream Forward Jets and Downstream Backward Jets. Energies. 2024; 17(14):3387. https://doi.org/10.3390/en17143387

Chicago/Turabian Style

Shangguan, Yanqin, and Fei Cao. 2024. "The Evolution of Flow Structures and Coolant Coverage in Double-Row Film Cooling with Upstream Forward Jets and Downstream Backward Jets" Energies 17, no. 14: 3387. https://doi.org/10.3390/en17143387

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