Published Paper Details:

High thermal efficiency in a gas turbine engine can achieved by higher turbine entry temperature. However, this leads to a high thermal load which affects the durability of the turbine components. Therefore, improved cooling techniques such as film cooling and internal cooling are applied to turbine blades. Internal cooling is achieved by circulating low enthalpy air in multi-pass flow channels inside the blade structure. To increase the heat transfer of the internal cooling, the internal surfaces usually are roughened by angled ribs to trip the boundary layer and increase turbulence. A Computational Fluid Dynamics study will be carried out to obtain heat transfer data for a single pass and two-pass rectangular channel (aspect ratio 2:1) with smooth and ribbed surfaces for two channel orientations. The V-shaped ribs are placed on the leading and trailing surfaces of 4 different arrangements of 45 deg V-shaped ribs are studied. The Reynolds numbers for study are selected as 5000, 15000 and 40000 and the rib height to hydraulic diameter ratio is 0.092, the rib pitch-to-height ratio is 8. The CFD studies are carried out for the parallel 45 deg V-shaped rib arrangements, inverted 45 deg V-shaped rib arrangements, parallel inlet and inverted outlet and inverted inlet and parallel outlet to determine the better heat transfer and augmentation of the flow. CFD is used to predict the bulk temperature inside the duct passage from which heat transfer coefficient is arrived. Nusselt number comparison between the various arrangements gives the insight for the enhanced heat transfer. Through this study the enhancement of simple flat surface is achieved and outcomes can be applied for various engineering applications.