A novel ultra-compact combustor with low flow resistance for the aero-engine

The use of an ultra-compact combustor has the potential to enhance the lightweight and durable characteristics of aero-engines. To reduce flow loss and achieve stable combustion in a compact space, a novel ultra-compact combustor based on trapped-vortex combustion technology was proposed in this study. The impact of the secondary flow ratio (λ) on the flow and combustion characteristics was investigated through a combination of numerical and experimental analysis methods. The nonreacting flow results demonstrated that with increasing λ value, the large-scale streamwise vortex within the cavity gradually decreases and subsequently results in a more stable spanwise vortex. However, increasing the λ value results in higher flow loss, and the total pressure recovery coefficient ranges from 96.6 % to 98.8 % at Mach 0.28. The airflow residence time is less than 1.5 ms, which significantly influences the ignition performance. The combustion results showed that an increase in λ increases the combustion efficiency and reduces the outlet temperature distribution factor. In addition, there is a correlation between the CRT and the ignition fuel–air ratio (FAR). The higher the CRT is, the longer the fuel–air residence time and the lower the FAR. The ignition performance is highest at λ = 21.9 %, and the ignition FAR values range from 0.009 to 0.015. The strong-combustion zone is concentrated at the junction of the front wall of the cavity and the guide vane during stable combustion, and the combustion intensity is highest for λ = 20.1 % at the same equivalence ratio.