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<p>Curvature-induced variations in near-wall flow behavior complicate the design of efficient cooling strategies for gas turbine combustor liners. In the present study, the impact of complex curvature structures on near-wall flow and heat transfer characteristics has been numerically investigated using conjugate heat transfer simulations under three representative curvature radii: flat (<i>r</i>=∞), middle curvature (<i>r</i>=233 mm), and high curvature (<i>r</i>=83 mm). The fundamental mechanism is identified as curvature-induced centrifugal forces fundamentally altering the near-wall vorticity dynamics and pressure fields. Results show that high curvature suppresses the kidney-shaped counter-rotating vortex pair (CRVP) while establishing favorable pressure gradients, thereby enhancing coolant-wall attachment via centrifugal compression effects and improving spanwise film uniformity. These mechanisms collectively enhance both advection and conduction-based cooling performance, as being evidenced at a blowing ratio of <i>M</i>=2 where the cooling effectiveness of the high curvature model reaches 53.5%, representing a 26.4% increase over the flat model. Hole-internal flow analysis indicates that the expansion section velocity decreases by 23% under high curvature, promoting jet energy dissipation. Additionally, velocity uniformity in the <i>y</i>-<i>z</i> plane improves by 40%. These findings elucidate the flow and thermal mechanisms underlying curvature-enhanced film cooling and provide a curvature-geometry coupling strategy for advanced combustor liners design.</p>

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Mechanisms and Characteristics of Film Cooling Enhancement in Expanded Fan-Shaped Holes under Complex Curvature

  • 期刊论文

  • 发表日期：

    2026年5月23日

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  • Shaowen Luo,
  • Jingzhe Ai,
  • Jihao Sun,
  • Ningbo Zhao,
  • Hongtao Zheng

摘要

Curvature-induced variations in near-wall flow behavior complicate the design of efficient cooling strategies for gas turbine combustor liners. In the present study, the impact of complex curvature structures on near-wall flow and heat transfer characteristics has been numerically investigated using conjugate heat transfer simulations under three representative curvature radii: flat (r=∞), middle curvature (r=233 mm), and high curvature (r=83 mm). The fundamental mechanism is identified as curvature-induced centrifugal forces fundamentally altering the near-wall vorticity dynamics and pressure fields. Results show that high curvature suppresses the kidney-shaped counter-rotating vortex pair (CRVP) while establishing favorable pressure gradients, thereby enhancing coolant-wall attachment via centrifugal compression effects and improving spanwise film uniformity. These mechanisms collectively enhance both advection and conduction-based cooling performance, as being evidenced at a blowing ratio of M=2 where the cooling effectiveness of the high curvature model reaches 53.5%, representing a 26.4% increase over the flat model. Hole-internal flow analysis indicates that the expansion section velocity decreases by 23% under high curvature, promoting jet energy dissipation. Additionally, velocity uniformity in the y-z plane improves by 40%. These findings elucidate the flow and thermal mechanisms underlying curvature-enhanced film cooling and provide a curvature-geometry coupling strategy for advanced combustor liners design.