Effects of Hot Streak/Airfoil Ratio in a High Subsonic Single-Stage Turbine

Experimental data have shown that combustor temperature non-uniformities can lead to the excessive heating of first-stage rotor blades in turbines. This heating of the rotor blades can lead to thermal fatigue and degrade turbine performance. The results of recent studies have shown that variations in the circumferential location, or clocking, of the first-stage vane airfoils can be used to minimize the adverse effects of the hot streaks due to the hot fluid mixing with the cooler fluid contained in the vane wake. Less effort has been put into determining the effects of the hot streak/airfoil count ratio on the heating patterns of turbine airfoils. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed for a single-stage high-pressure turbine geometry operating in high subsonic flow. Simulations were initially performed without hot streaks to compare with the experimental data. The ratio of the number of hot streaks to the number of vanes and rotors was then varied. The predicted results demonstrate a complex interaction between the hot streak and the secondary flows in the rotor.

Effects of Hot Streak/Airfoil Ratio in a High Subsonic Single-Stage Turbine Academic Article