Effect of radial hot streak position on heat transfer in a reverse-flow combustor coupled with turbine guide vanes

Abstract

The ongoing pursuit of higher thrust-to-weight ratios in aero-engines has intensified aerodynamic and thermal coupling between combustors and turbines, especially in reverse-flow combustor configurations with compact hot-end layouts. This study presents a novel experimental and numerical investigation of hot streak dynamics and their impact on turbine guide vane (TGV) heat load. A high-fidelity test rig featuring a three-head sector reverse-flow combustor and six TGVs, combined with a dual-stage radial swirler, was developed to evaluate the circumferential and radial temperature distribution at the combustor outlet under representative conditions. Experimental measurements and computational simulations revealed that strategic adjustment of the dilution hole areas in the inner and outer liners enables precise control over the radial positioning of hot streaks. By increasing the inner liner dilution area while proportionally decreasing the outer liner dilution area—thus maintaining a constant total dilution area—the central position of the hot streak is shifted from the upper region to the midsection. This adjustment results in a peak temperature reduction of up to 6.4 % and a 15 % decrease in OTDF, effectively lowering the outlet temperature distortion factor (OTDF) and achieving a more uniform temperature distribution at the combustor exit. This modification not only lowers the temperature and static pressure on the guide vane surface but also significantly alleviates high-temperature ablation at the vane’s upper region. These findings advance understanding on combustor-turbine thermal interaction and inform optimized cooling strategies for advanced aero-engines.