Evaluation of Novel Junction Film Holes for Improving Film Cooling Performance

  • HE Juan ,
  • CHEN Lei ,
  • NI Qin ,
  • XIAO Kun ,
  • PENG Hao
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  • 1. Jiangsu Key Laboratory of Process Enhancement and New Energy Equipment Technology, School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, China
    2. Nanjing Yuqing Environmental Technology Co., LTD, Nanjing 211500, China
    3. Jiangsu Province Key Laboratory of Aerospace Power System, College of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China

Online published: 2025-07-04

Supported by

The computational data presented in the current paper was obtained through the support of National Natural Science Foundation of China (No. 22408157), Postdoctoral Fellowship Program of CPSF (GZB20230305) and Jiangsu Province Provincial Department of Science and Technology (No. BK20241413).

Copyright

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

Abstract

The junction film cooling has been proposed to deal with the situation of insufficient film cooling performance under limited coolants. Numerical investigations are performed for baseline case and four junction film hole cases (3_junction, 4_junction, 5_junction and 6_junction cases) at the coolant mass flow rate varying from 0.0016 kg/s to 0.0064 kg/s. From the results, due to the expanded film hole exit and the interactions between branch film jets, junction film hole cases can suppress the “injection phenomenon” of film jet and the “entrainment effect” of mainstream, thus to improve film cooling performance, especially the film spanwise coverage. By comparison, under low coolant mass flow rate, the 5_junction case can generate the most obvious film cooling performance improvement. To be specific, at the coolant mass flow rate of 0.0016 kg/s, it achieves 76.92% improvement in area-averaged adiabatic film cooling effectiveness, and at the coolant mass flow rate of 0.0032 kg/s, the improvement is up to 703.85%. Through flow loss analysis, the results show that at low coolant mass flow rate, the junction film hole cases improve film cooling performance and pay a little cost of pressure loss; but under high coolant mass flow rate, they can improve film cooling performance and reduce total pressure loss concurrently. Among them, the 5_junction case generates the lowest total pressure loss coefficient; corresponding to the coolant mass flow rate of 0.0048 kg/s and 0.0064 kg/s, it decreases by 15.90% and 41.58% respectively. Through this study, the junction film cooling for improving cooling performance is provided, which is conducive to further raising turbine intake temperature, thereby improving the kinetic and thermodynamic properties of gas turbines.

Cite this article

HE Juan , CHEN Lei , NI Qin , XIAO Kun , PENG Hao . Evaluation of Novel Junction Film Holes for Improving Film Cooling Performance[J]. Journal of Thermal Science, 2025 , 34(4) : 1431 -1449 . DOI: 10.1007/s11630-025-2143-0

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