Numerical Comparison of Heat Transfer and Pressure Drop in Gas Turbine Blade Cooling Channels With Dimples and Rib-Turbulators

In order to enhance the performance of a gas turbine and to maintain the blade material within operating temperature range, cooling channels are made within the blade materials that extract the heat. The walls of these cooling channels are usually enhanced with some sort of turbulence generators — ribs and dimples being the most common. While both the geometries provide improvement in enhancing the heat transfer, dimples usually have a lower pressure drop. It is essential to improve the heat transfer rate with a minimal pressure loss. In this study, the heat transfer and pressure loss are determined numerically and combined to show the effect of both in channels with ribs and dimples on one wall of the channel. Similar geometric and boundary conditions are used for both the turbulators. Reynolds numbers of 12,500 and 28,500, based on the hydraulic diameter are used for the study. The Reynolds-Stress Model was used for all the computations as a turbulence model by employing Fluent.