Simulation of Heat Transfer in A Ribbed Channel of A Gas Turbine Blade

Cooling of blades is a challenge in advancement of gas turbines. Channels are used inside the blades to improve the heat transfer. Repeated ribs have significant impact on the heat transfer and pressure drop characteristics of a channel. In this study the effect of ribs with specified geometry is numerically investigated. In a relatively large range of Reynolds from 10000 to 80000, the fluid flow and heat transfer were simulated. The finite volume method was implemented. To model the turbulence, the standard k– ε model was used. The thermal boundary condition was the constant heat flux at the channel surfaces. The magnitude of the heat flux was assigned in a way to result in temperature difference from 10 K to 15 K. The results of current research were compared to the available experimental data under similar flow conditions. The coefficient of pressure drop was comparable with experimental data both in two dimensional and three dimensional cases. In the two dimensional simulation, the heat transfer coefficient was similar to the experimental data in the range of this study. In the three dimensional simulation, accuracy of the heat transfer coefficient in the case of low Reynolds was not satisfactory. However, it improved progressively as the Reynolds number increased. It was observed that, the maximum improvement in the heat transfer and pressure drop are about more than 200% and 300% respectively. Heat transfer augmentation could be explained by the presence of the secondary flows and disruption of the boundary layer growth due to the ribs.