The ignition performance of the spray flame is an important safety parameter in a gas turbine combustor. Previous studies have shown that the spark axial location has a significant influence on the ignition performance and flame propagation process, and further research is required. The ignition performance and flame kernel propagation at different spark radial locations in a gas turbine model combustor are studied experimentally in this paper to summarize the influence of spark location on ignition performance from the perspective of kernel propagations, and to find the optimal ignition location. The flame propagation trajectory of each ignition location is obtained through high-speed imaging tests. Four conclusions are obtained as follows: 1) In a successful ignition event, flame kernels from different ignition positions will eventually propagate to the same position, which is defined as the flame holding position (FHP). After the flame residence stage, the kernel will begin to grow until the entire combustor is ignited. The FHP is with low axial velocity, small turbulent fluctuation and appropriate fuel concentration to effectively maintain the flame. 2) The ignition performance is the worst when the ignitor is near the wall, and is the best when the ignitor is near the FHP, that is, the inner boundary of the recirculation zone. 3) The ignition performance deteriorates if the flame has to cover greater distances before reaching the FHP where it can ignite the flame stabilization zone. A spark at the FHP can greatly reduce the propagation distance of the flame kernel, thereby avoiding the obstruction of the propagation process. 4) The propagation trajectory of the flame kernel is related to the ignition location and is mainly controlled by the non-reacting flow field and fuel concentration. (C) 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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