Numerical Analysis of Film-Cooling Performance and Optimization for a Novel Shaped Film-Cooling Hole
In the present work, a numerical study on a novel shaped film-cooling hole has been performed. The novel shaped hole is designed to enhance lateral spreading of coolant on the cooling surface. The film-cooling performance of the novel shaped hole is compared with the fan, laidback fan, and dumbbell shaped film-cooling holes at density ratio of 1.75 in the range of blowing ratio from 0.5 to 2.5. The optimization of the novel shaped hole has been carried out to increase film-cooling effectiveness with four design variables, i.e., lateral expansion of the diffuser, forward expansion angle of the hole, length to diameter ratio of the hole, and pitch to diameter ratio of the hole. To optimize the hole shape, the radial basis neural network model is constructed and sequential quadratic programming is used to find optimal point from the surrogate model. The novel shaped hole shows remarkably improved film-cooling performance in comparison with the other film-cooling holes. The novel shaped hole modified by the optimization gives enhanced performance in comparison with the reference geometry.