Conjugate Study of Aerothermodynamics of Internal Ridged-Wall Enhanced Swirl-Film Cooling for Gas Turbine Blade Leading Edge

Abstract

This article introduces a high-performance swirl-film conjugate cooling scheme with the novel ridged wall for the leading edge of a gas turbine blade and presents a numerical study of the aerothermal characteristics of the conjugate cooling using a conjugate heat transfer analysis. Aiming at further improving the cooling efficiency of the turbine blade leading edge, a novel scheme of enhanced swirl-film conjugate cooling with an internal ridged wall is proposed. The complex flow and heat transfer interactions on the blade leading edge cooling effectiveness are studied, including the external main flow, film injection jets, solid wall heat conduction, and internal coolant jets impingement on the curved wall. Detailed aerothermal characteristics of the swirl-film conjugate cooling are presented and compared with each other by analyzing the leading edge external and internal flow structures, heat transfer, and pressure loss under three different jet-wall configurations and for various blowing ratios. The numerical results are effectively validated by the steady-state infrared thermography experimental data. The results indicate that within the range of parameters studied, compared to the baseline leading edge jet impingement-film cooling, swirl-film cooling has increased internal heat transfer rates with more uniform distributions and an even lower internal pressure loss penalty. The averaged Nusselt numbers of the swirl-film cooling with a smooth curved wall can be increased by more than 30.2%, and the overall cooling effectiveness of the leading edge can be increased by 4.8–5.7%. In addition, the pressure loss is reduced by 9.3–10.3%. Furthermore, the proposed ridged wall enhanced swirl-film cooling exhibits superior cooling performance. Specifically, it increases the average Nusselt numbers of internal swirl cooling by over 54%, enhances the overall cooling effectiveness of the leading edge by 8.0–10.1%, and reduces pressure loss by 8.1–9.9%.