Numerical study on heat transfer and fluid flow in pin fin-dimple channels with fillet on dimple edge

Pin fins and dimples are used for enhancing heat transfer from surfaces and here we take into account their use in cooling the trailing edge of gas turbine blades. The main problem is the increase in pressure drop with increase in dimple depths. This is a vital factor for the total work done by the turbine. The models for which study has been conducted are the ones with dimple depths of 1mm, 2mm and 3mm. Also, as a modification, fillets are added to the edges of the dimples with 3mm depth. Turbulent flow with Re of about 55,000 is employed through the surface, which is heated with constant heat flux of 50,000 W/m². The results showed that the modified model reduces the frictional loss to a large extent without creating much disturbance to the heat transfer capability of the original structure. The modified model gave the lowest amount of friction factor at the same time providing reasonable amount of heat transfer compared to the other three models.