Ignition and Lean Blowout Performance of an Annular Mixed-Flow Trapped Vortex Combustor Under Sub-Atmospheric Pressure

In this paper, ignition and lean blowout (LBO) performance of an annular mixed-flow trapped vortex combustor (MTVC) were investigated under sub-atmospheric pressure. Experimental investigations were conducted to evaluate the ignition and lean blowout (LBO) performance under various sub-atmospheric pressure conditions. The findings indicate that MTVC has excellent ignition performance, the ignition pressure of the combustor can reach 35.3 kPa under ambient temperature, and the corresponding altitude is close to 8,000 m. As the pressure drops, the range of ignitable velocities diminishes, leading to increase in ignition fuel to air ratio (FAR) and LBO FAR. These shifts can be attributed to the more challenging combustion conditions and heightened inlet velocity resulting from reduced pressure. Notably, the ignition and LBO performance see substantial enhancements with rising temperatures. However, the positive impact of elevated temperature hardly compensated for the detrimental impact of lower pressure on ignition. There is minimal noticeable impact of the inlet Mach number on the ignition and LBO performance. Numerical simulations are carried out for both unreactive and reactive flow to verify the experiment results.