NUMERICAL INVESTIGATION OF HEAT TRANSFER ENHANCEMENT IN GAS TURBINE BLADE BY AIR FILM COOLING AND DIFFERENT TYPES OF RIBS

摘要

In this research, numerical studies have been carried out for a film cooling jet on a gas turbine blade in the presence of different kinds of ribs. Simulations are performed for a film cooling jet inclined at 30-degrees. The effect of coolant jet velocity on convection heat transfer coefficient (h) is investigated. In addition, various ribs geometries and their distance from the blade surface are examined. It is shown that a combination of the rib and the film cooling jet stimulate the momentum and thermal boundary layers and subsequently improve the convection heat transfer coefficient. It is indicated that the heat transfer coefficient is dependent on the height of the rib and there is an inverse relation with the rib distance from the plate. Moreover, an increase in coolant jet velocity causes the increase of the heat transfer coefficient. The results show a significant improvement of the heat transfer coefficient over three times more than h on a blade without any ribs or coolant jet.