Optimal Design and Analysis of the Cooled Turbine Blade in Gas Turbines with CFD

In this study, the effects of the structural geometries of the channels used for cooling blades in the heated regions of the gas turbine exposed to high temperature were investigated. It is aimed to cool the gas turbine blade using 10 different types of ribbed channels by simulation method. Roof, inverted roof, slope and wedge ribs with standard and stepped arrangements developed for improving thermal performance in a rectangular cooling duct with a 4:1 ratio aspect were studied. Square type rib, the basic geometry is designed to make thermal comparisons. Details of turbulent flow and numerical calculations were made using of the standard k-ε turbulence model by means of the Computational Fluid Dynamics (CFD) method. The heat transfer in ribbed walls was examined in four different Reynolds numbers, 10000, 20000, 40000 and 80000 according to the channel input cross section. As a result of the calculations, the temperature changes of the turbine blade depending on Re number, the heat transfer improvement occurring in the internal channels inside the blade and the overall thermal performance were compared. The different types of rib evaluated in the study were compared with the standard-square rib; higher Nu number was obtained in stepped-wedge rib, stepped-roof rib, stepped-slope rib and stepped-inverted roof rib, respectively. It has been observed that a stepped-wedge rib can improve overall thermal performance and is promising for internal turbine blade cooling applications. The best operating range of all models was found to be between Re=40000 and Re=80000. The highest PEC results were obtained in the stepped-wedge rib model. This is 3.37% higher than the closest performing stepped-inverted roof rib model with 5.04 at Re=8000.

Optimal Design and Analysis of the Cooled Turbine Blade in Gas Turbines with CFD Keywords:

Gas turbines , Blade cooling , Computational fluid Dynamic , Rib , Optimization