Film-Cooling Effectiveness Investigation of Various Diffusion Slot Hole Geometries on Turbine Guide Vane Endwall

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  • 1. Advanced Gas Turbine Laboratory, Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
    2. School of Aeronautics and Astronautics, University of Chinese Academy of Sciences, Beijing 100049, China
    3. National Key Laboratory of Science and Technology on Advanced Light-Duty Gas-Turbine, Beijing 100190, China
    4. Key Laboratory of Advanced Energy and Power, Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China

Online published: 2026-01-05

Supported by

The work is supported by the financial support from National Science and Technology Major Project of China (J2019-III-0007-0050).

Copyright

Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2025

Abstract

Endwall film-cooling effectiveness experiments were conducted on a turbine guide vane using pressure sensitive paint measurement technique. Four film hole geometries, i.e., a fan-shaped hole, a horizontal slot hole, and two vertical slot holes with different expansion angles, were tested under a film hole layout that considered the actual multi-chamber construction. A continuous slot was set upstream of the endwall film holes to examine the influence of the upstream cooling. The experiments were performed at a mainstream Reynolds number of 620 000, a mainstream turbulence intensity of 3.7%, and a coolant-to-mainstream density ratio of 1.5. The results showed that the vertical slot holes perform better in the various chamber zones on the endwall than other hole geometries, in particular the zone with highly accelerated mainstream and the zone with large orientation angle. The vertical slot hole with a large exit expansion angle always yields the highest effectiveness on the endwall. The upstream slot cooling remarkably improves the endwall effectiveness and the influences are almost consistent for various hole geometries. Compared with the baseline fan-shaped hole, from blowing ratios of 1.0 to 2.5, the increase in the area-averaged effectiveness by large expansion angle vertical slot hole reaches 10.7%–39.1% without upstream slot cooling, while with upstream slot cooling, the increase decreases to 4.9%–23.1%. The discharge coefficient of various hole geometries on the endwall has almost no difference at small blowing ratios, and the difference at medium and high blowing ratios is also not great.

Cite this article

MA Xiaohui, HU Jiajun, AN Baitao . Film-Cooling Effectiveness Investigation of Various Diffusion Slot Hole Geometries on Turbine Guide Vane Endwall[J]. Journal of Thermal Science, 2026 , 35(1) : 115 -131 . DOI: 10.1007/s11630-025-2210-6

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