NUMERICAL STUDY OF A NOVEL DIVERGING-EXIT HOLE FOR IMPROVED FILM COOLING PERFORMANCE

Articles in Press

Document Type : Full Length Research Article

Authors

Aero Hydrodynamic Naval Laboratory, (LAHN) USTO-MB, Oran, Algeria University of Science and Technology of Oran, MOHAMED BOUDIAF Faculty of Mechanical Engineering, BP1505 El-MNAOUAR, 31000, Oran, Algeria

Abstract

This study numerically investigates a series of novel lip-shaped divergent-exit hole configurations designed to enhance film cooling effectiveness on turbine blade surfaces. Six configurations were analyzed Full Lip (FL), Oval Lip (OL), Oval Upper Lip (OUL), Oval Lower Lip (OLL), Full Upper Lip (FUL), and Full Lower Lip (FLL) using Reynolds-Averaged Navier–Stokes (RANS) simulations with the RNG k–ε turbulence model. The computational results were validated against experimental data for a baseline cylindrical hole at multiple blowing ratios (M = 0.5, 1.0, and 1.5). The findings indicate that all lip-shaped geometries improved the laterally averaged film cooling effectiveness compared with the conventional cylindrical hole, with the FL configuration exhibiting the most consistent performance. At M = 1.5, the FL hole achieved up to 100% enhancement in film cooling effectiveness relative to the baseline, primarily due to improved coolant attachment and suppression of jet lift-off. These results demonstrate the potential of asymmetric lip-shaped exits to achieve more uniform cooling coverage and higher thermal protection under realistic turbine operating conditions.

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Journal of Heat and Mass Transfer Research

Articles in Press, Accepted Manuscript
Available Online from 29 November 2025

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History

  • Receive Date: 08 August 2025
  • Revise Date: 10 November 2025
  • Accept Date: 29 November 2025

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