Investigation of ignition process of a multi-swirl staged model combustor in low-temperature environment

•The TF model based on FLUENT undergoes secondary development. By loading UDFs, the DTF model is applied on FLUENT to simulate turbulent combustion.•LES-DTF method coupled with the skeletal mechanism of kerosene is used to investigate the influence in ignition process under low-temperature inlet.•The key factors that influence the ignition process in the cold flow field are analyzed.•The reasons why low-temperature inlet and high oil gas ratio affect the ignition process are discussed. The ignition reliability of lean combustion is fundamental to make sure that gas turbine combustor can operate in low-temperature environment reliably. It is important to investigate the influence of key factors on ignition process to improve ignition performance. Based on the multi-swirl staged model combustor, the effect of low-temperature inlet and fuel to air ratio (FAR) on the behaviors of the initial flame kernel and flame propagation. In this work, Large Eddy Simulation (LES) and Dynamic Thickened Flame (DTF) model coupled with skeletal chemical reaction mechanism of kerosene are used to capture flamelet information during the ignition process. The results show that the numerical method can capture the ignition process accurately. The axial velocity, droplet temperature and local equivalence ratio of the ignition position decrease as the inlet air temperature decreases, while the local equivalence ratio increases with the increase of FAR. Ignition fails when inlet air temperature reducing to 253 K, as local equivalence ratio and local FAR decrease, and the Karlovitz number (Ka) of the ignition position increases. The ignition with low-temperature inlet air can be successful by raising the FAR to 0.04 at the same time, but the ignition delay time is extended by 26.72 % and the flame propagation path is changed.