Investigations of the effect of dome spacing on ignition performance of a model combustor with RP-3 liquid aviation fuel

Dome spacing is one of the most critical factors to affect the ignition performance of the aerospace engine. In this paper, a three-dome model combustor is designed to investigate the effect of dome spacing on ignition performance with RP-3 liquid aviation fuel. The dome spacing considered are 48 mm, 60 mm, 72 mm, respectively, and the effect on ignition performance including ignition and propagation limits are revealed by a combustion experiments under ambient temperature and pressure, and the reference velocity is from 3 m/s to 8 m/s. The ignition performance is evaluated in terms of the fuel/air ratio, at which ignition occurs. The results show that the best ignition performance is achieved when the dome spacing is 60 mm. Furthermore, numerical simulations with validated methodology of non reacting flows inside the combustor have been conducted. The results show that when the dome spacing is 60 mm, the best mutual support between adjacent domes is attained according to the maximum value of mergin rate and dimensionless width of central toroidal recirculation zone. Besides, the restrictive effect of the primary hole jet on the central toroidal recirculation zone is found to be increased with the decrease of dome spacing.