Performance evaluation of a converging-diverging film-cooling hole

초록

A converging-diverging film-cooling hole was designed by combining a converged inlet with a fan-shaped exit. The performance of the proposed design was analyzed numerically and compared to that of a fan-shaped hole. The film-cooling effectiveness was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model. The numerical results for fan-shaped and cylindrical holes were compared with previous experimental data. Compared to the fan-shaped hole, the converging-diverging hole improved the spatially averaged film-cooling effectiveness by 4.3%, 5.9%, and 9.9% at blowing ratios of 0.5, 1.0, and 1.5, respectively. These improved film-cooling performances were achieved by reducing the size of the separation bubble in the hole, thus increasing the thickness of the coolant layer downstream of the hole.

키워드