Thermal and Hydraulic Performance of Single-Stage Swirling Impinging Jet Array for Cooling of the Liner of Industrial Gas Turbine Combustor

Stringent global regulations increasingly demand significant reductions in emissions from industrial gas turbines, underscoring the need for optimized combustor liner cooling to achieve lower emissions and enhanced thermal efficiency. Uniform liner temperature is crucial, as it minimizes thermal stresses, reduces fuel consumption, and improves component reliability. Although impinging jet arrays with flow passages are widely utilized for cooling, cross-flow effects can diminish heat removal efficiency from the target surface. In contrast, the induction of swirl has the potential to improve heat transfer and its distribution uniformity. This study investigates the impact of varying swirl intensities, induced by incorporating a cross-twisted tape into the nozzle, on the flow and heat transfer characteristics of the jet array. Six twisted angles (0°, 15°, 30°, 45°, 60°, and 75°) were evaluated, where the introduction of the twisted tape divided the jet into four streams, leading to complex interactions that alter the cooling performance at the target surface. The results show that moderate swirl angles (15° and 30°) enhance temperature uniformity and provide more consistent heat transfer across the surface compared to higher swirl or no swirl. However, excessive swirl (60° and 75°) can hinder jet penetration and reduce cooling effectiveness in downstream regions. Overall, the introduction of swirl improves temperature uniformity but also increases pressure drop due to heightened turbulence.