Investigation of flow interaction and the impact on flame propagation in an annular combustor with centrally staged burners

This paper presents a comprehensive experimental and numerical investigation of a centrally staged annular combustor, aiming to analyze the flow interactions between adjacent burners and their effects on flame propagation in the light-round process. Moreover, the current study provides new insights into flow dynamics and their impact on flame propagation, offering valuable guidance for the design of annular combustors. Experimental measurements of longitudinal and circumferential flow distributions across multiple burners are conducted using Particle Image Velocimetry (PIV) and serve to validate corresponding Large Eddy Simulation (LES) calculations. The results reveal that a longitudinal bridge flow connects the main jet with the recirculating flow between the two adjacent burners, forming an inner recirculation zone (In-RZ) in the interaction region. Flow interactions cause disruptions in circumferential swirling flows, resulting in low-velocity flows between the adjacent burners and high-velocity flows along the walls. Additional simulations are conducted to examine the three-dimensional flow interaction and the influence of burner-burner spacings on the flow dynamics. High-speed imaging captures flame propagation sequences in clockwise and anti-clockwise directions, revealing the influence of flow interactions on flame propagation under varying operating conditions. Therefore, the current investigation concluded that the longitudinal and circumferential flow interactions significantly influence the flame propagation patterns and should considered in the burner design.