Abstract
In this paper we consider the impact of trailing edge burn-back on the aerodynamic performance of cooled transonic high-pressure nozzle guide vanes. We consider four levels of burn-back ranging from new parts to severely damaged parts. High-fidelity experimental aerodynamic performance data was taken in the Engine Component AeroThermal facility at the University of Oxford, at engine matched conditions of Mach number, Reynolds number, and coolant-to-mainstream pressure ratio. Experimental data are compared to results of computational fluid dynamics simulations to provide further insights into the mechanisms affecting performance. We find that for fixed row pressure ratio, increasing burn-back leads to: both increased loading, and increased forward loading; increased film cooling flow due to re-loading and increased trailing edge flow due to slot area increase; increased overall boundary layer loss; a significant increase in exit secondary kinetic energy associated with newly formed counterrotating vortices at the edges of the burn-back region; and increased variation in exit whirl angle. We quantify these effects and consider implications for whole-life engine performance.
