Film cooling is vital to gas turbine blades to protect them from high temperatures and hence high thermal stresses. In the current work, optimization of film cooling parameters on a flat plate is investigated numerically. The effect of film cooling parameters such as inlet velocity direction, lateral and forward diffusion angles, blowing ratio, and streamwise angle on the cooling effectiveness is studied, and optimum cooling parameters are selected. The numerical simulation of the coolant flow through flat plate hole system is carried out using the “CFDRC package” coupled with the optimization algorithm “simplex” to maximize overall film cooling effectiveness. Unstructured finite volume technique is used to solve the steady, three-dimensional and compressible Navier-Stokes equations. The results are compared with the published numerical and experimental data of a cylindrically round-simple hole, and the results show good agreement. In addition, the results indicate that the average overall film cooling effectiveness is enhanced by decreasing the streamwise angle for high blowing ratio and by increasing the lateral and forward diffusion angles. Optimum geometry of the cooling hole on a flat plate is determined. In addition, numerical simulations of film cooling on actual turbine blade are performed using the flat plate optimal hole geometry. 1. Introduction Over the past fifty years, aircraft and power generation gas turbine designers have focused on increasing the temperature at the combustor exit to improve the engine performance, to increase the thrust, and to reduce the fuel consumption. Unfortunately, these high temperatures have a negative effect on the integrity of the high-pressure turbine components specifically the turbine blades. Therefore, there is a need to have an efficient cooling system engineered in a way such that the maximum blade surface temperature during the engine operation does not exceed the maximum allowable temperature of the blade material. To achieve this goal, several researchers such as [1, 2] focused on various innovative cooling techniques. Depending on the nature of the coolant flow, the cooling methods currently implemented in the turbine industry can be classified into two main categories which are the internal and external cooling as shown in Figure 1. In the first type cooler air is bled from the compressor stage and then passed through internal passages incorporated into blade designs for this purpose. This is the most common technique and is called enhanced passage cooling. For maximum heat absorption, the air is
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