Numerical investigation on flow field and heat transfer in the combustor coupled with turbine guide vanes under different contraction ratios

As the thrust-to-weight ratio of aero-engines increases, combustor outlet temperature rises significantly, posing substantial challenges for turbine cooling design due to enhanced turbulence, residual swirl, and temperature distortions. The introduction of lean-burn combustors has further complicated the situation, resulting in more compact engine components and intensified interactions between the combustor and turbine stages.

Existing studies on combustor-turbine coupling primarily focus on the influence of electrically heated simulated hot streak on turbine aerodynamics and heat transfer under non-reactive conditions. This study introduces an integrated test rig featuring a triple combustor and turbine guide vanes (TGVs) equipped with advanced lean-burn dual-stage swirlers. The large eddy simulation is utilized to study the influence of TGVs on the flow field and combustion characteristics within the combustor under different contraction ratios (CR).

Numerical results demonstrate that different TGVs geometric configurations significantly affect the flow and heat transfer characteristics within the combustor under different CR with varying throat Mach number. TGVs significantly alter the pressure gradient distribution within the combustor. As the CR increases, the jets penetration from dilution holes become deeper, intensifying temperature distortions at the combustor outlet. Additionally, the accumulation behavior of film coolant near the combustor outlet changes markedly due to the blocking effect of the TGVs, potentially impacting film cooling efficiency, particularly near the hub and shroud regions. Furthermore, the study reveals that variations in the relative positioning of the TGVs and the dilution holes result in distinct differences in dilution jet behavior and film coolant distribution within the combustor. These findings highlight the critical need for an integrated combustor–turbine co-design strategy to effectively manage thermal loads and flow interactions in advanced aero-engine architectures.