Effect of Rotation on Heat Transfer and Flow Field Inside Leading Edge Cooling Passage Using Impinging Jets

In this paper, the effect of rotation on impingement cooling on the internal surface (profile) of the leading edge region in a turbine rotor blade is investigated using Computational Fluid Dynamics (CFD) simulations. The flow domain is obtained by stretching the middle cross section of the blade. The simulations are performed for 3 different leading edge profiles to increase the heat transfer rate in the cooling flow passage in stationary domain. In all the profiles, the nozzle position and Mach number of cooling fluid is kept constant at E/D = 4.32 and 0.4 respectively. In the profile 1, the suction side profile is modified to facilitate vortex shift so that it may reduce the crossflow effect which will enhance the Nu_avg. But Nu_avg reduced by 1.9% when compared to base case. In the profile 2, the coolant flow passage is smoothened at the apex to reduce dead zones and to enhance spreading of the jet. In this case, a 3.48% increase in Nu_avg is obtained. Based on the analysis of velocity contours in the profile 2, the leading edge profile is further modified (profile 3). This resulted in 5.37% increase in the Nu_avg. The effect of rotation on the Nu_avg for different Mach numbers (M) in the profile 3 and base case are studied. When compared to stationary domain Nu_avg is reduced for base case and profile 3. In rotating domain profile 3 shows improvement for different M when compared with base case. For M = 0.2, the Nu_avg is increased by 2.7%, for M = 0.4, Nu_avg is increased by 3.98% and for M = 0.6, it is negligible.