Study on flow and heat transfer in a finned internal cooling duct

This study focuses on the characteristics of three-dimensional turbulent flow field, heat transfer enhancement, and average duct pressure loss in a finned internal cooling duct for gas turbine blades. An experimental module was set up to analyze the flow properties. Based on the experimental data, the conventional k-ε turbulence model and standard wall function were applied to predict the 3D turbulent flow and heat transfer. A complicated 3D-accelerated spiral flow in the helical-finned duct becomes more remarkable with the increasing value of the guide angle, α, owing to the presence of helix-like cuneiform fins. This feature of the fluid flow causes significant effects on heat transfer enhancement as well as the pressure loss. A detailed discussion on the influence of the guide angle, α, and the coolant flow directions on the 3D flow field characteristics, average Nusselt number, and resistance coefficient inside the duct are presented in this study. In addition, the most efficient geometrical structure parameters of the helix-like cuneiform fins in the internal cooling duct are obtained based on the results of the numerical investigation of all cases studied. The results can be applied in designing the internal cooling duct of gas turbine blades and in designing a potential alternative cooling configuration.