Investigation of the effects of flame surface development on the ignition mechanism of aero-engine combustors

• Published in: Proceedings of the Institution of Mechanical Engineers. Part G, Journal of aerospace engineering Journal of aerospace engineering, 2023-11, Vol.237 (14), p.3255-3271
• Main Authors: Zhang, Qun, Wang, Zixin, Yang, Fuzheng, Wu, Zhidi, Hu, Fan, Wang, Xiaoyan, Gao, Yaohong, Ma, Xiaoxi
• Format: Article
• Language: English
• Subjects: Combustion chambers; Flame propagation; High speed photography; Ignition; Kernels; Large eddy simulation
• ISSN: 0954-4100; 2041-3025
• DOI: 10.1177/09544100231185226

Large eddy simulation was employed to simulate the effects of different vane angles of the primary and pilot stages on the ignition process of a combustor under normal temperature and pressure conditions. The simulation results of different vane angles of the pilot stage were then verified experimentally. Kernel initiation and flame propagation in the cases of ignition success and failure were analysed. It was found that in the ignition failure case, the flame kernels are confined to the downstream zones of the venturi and cannot propagate radially, and almost no negative displacement exists in the axial direction. However, in the ignition success case, sub-fire kernels are always present outside the radial boundary of the primary stage. Five ignition modes were finally proposed: (I1) typical ignition, (I2) relatively high-speed ignition, (I3) single-kernel alternating dominant, (I4) main kernel dominant, and (I5) dual-kernel dominant modes. Using high-speed photography, the flame shape changes and ignition characteristics in the cases of successful and failed ignition with different pilot-stage vane angles were investigated.