Study on the effects of dimple density and dimple diameter on heat transfer and flow resistance in rotating dimpled channels

Dimpled cooling channels are a promising solution for enhancing the cooling performance of rotating turbine blades, but their practical application is hindered by the lack of systematic studies on the interplay between geometric parameters and rotational effects under realistic conditions. This study provides an in-depth analysis of the effects of dimple density, diameter, and rotational conditions on heat transfer and flow resistance in cooling channels. The research reveals that increasing dimple density enhances heat transfer, particularly at lower Reynolds numbers, though this effect diminishes at higher Reynolds numbers, indicating a threshold beyond which further increases in density offer limited benefits. Similarly, larger dimple diameters improve heat transfer by promoting earlier flow reattachment and increased turbulence within the dimples, especially under high Reynolds numbers. The study also highlights the significant impact of rotational effects, where channels with smaller dimple diameters show a greater sensitivity to rotation, resulting in substantial heat transfer improvements. Flow resistance trends are also explored, showing that while resistance increases with dimple density and diameter, it stabilizes at higher Reynolds numbers, suggesting that an optimal balance between heat transfer enhancement and manageable flow resistance can be achieved. These findings provide valuable insights for the design of cooling channels in turbine blades, demonstrating that by carefully selecting dimple geometries and considering rotational effects, it is possible to maximize heat transfer while minimizing flow resistance, thereby enhancing the overall efficiency of cooling systems in high-performance turbines.