Study on the Influence of the Pilot Stage Swirl Intensity on the Double-Swirl Combustor’s Ignition Process via Large Eddy Simulation

The ignition reliability of the combustion chamber is crucial for the overall performance of an engine. As the aero-engine combustion chambers continue to advance, the scope of the ignition problem has also expanded. This study employs large eddy simulation to investigate the flow characteristics and ignition process of a double-swirl combustor. The non-reacting flow field and ignition propagation process are acquired using particle image velocimetry (PIV) and high-speed cameras. Experimental findings are employed to validate the numerical simulations. The results demonstrate a close relationship between the ignition process of the double-swirl combustor and the flow field within the combustor. Following the spark discharge, a core is generated at the edge of the recirculation zone. Over time, the spark gradually propagates towards the center of the combustor along the direction of swirl due to the flow. Once the flame reaches the head, the fuel and gas mixture ignited by the core within the recirculation zone stabilizes within the boundary layer of the primary and pilot stages. The flame continues to propagate throughout the combustor until complete ignition is achieved. Additionally, the swirl intensity of the pilot mode is identified as a key factor influencing the ignition propagation process of the double-swirl combustor.