Research On The Simulation And Characteristics Of Ignition In Aeroengine Combustor

The reliability of ignition and the stability of combustion in main combustion chamber is animportant performance parameters of aircraft engines, to accurately predict ignition and flameoutperformance of combustor has important significance for the design and work of engines. Based onthe commercial software FLUENT, numerical simulation investigation was conducted on the processand characteristics of ignition in combustor. Firstly, In order to establish a credible calculationmethod for ignition prediction, experimental data obtained from a model combustor with vaporativeflameholder was used to validate numerical simulation results. Then a two-phase three-dimensionalsteady combustion and ignition process of a single head and a multi-head annular combustor modelwere simulated. Furthermore, a series of research were conducted which focused on cold flowdistribution, fuel concentration distribution, temperature distribution and performance of ignition andflameout in combustor. The main results include:(1)The flow field and combustion characteristics of model combustor with vapor flameholderunder different inlet Mach number were numerical simulated, The lean ignition and blowout limitwas predicted using fuel steady stepwise method. The results were, compared with the experimentaldata in order to verify the numerical calculation method used in this paper. Research results show thatlean ignition and blowout limit predicted by fuel steady stepwise method is reliable.(2)Simplified model of single head annular combustor was established, cold and hot flowfield ofcombustor model were calculated on constant start inlet condition, and the steady flow characteristicsand lean ignition and blowout limit of single head annular combustor were obtained. Appropriatechemical reaction mechanism of aviation kerosene were choosed to calculate the combustionflowfield, also Laminar Flamelet model was introduced in combustion simulation to compare withEDC model. The results show that: Combustor temperature of each section simulated by multi-stepreaction mechanism was obviously lower than one-step reaction mechanism; while the hightemperature region in the combustion zone moved forward in Laminar Flamelet model simulationcompared with EDC model.(3)Based on steady simulation of single head annular combustor, taking cold flowfield andconcentration field as initial value of ignition simulation, and taking a small fixed high temperatureregion as ignition source, unsteady simulation about ignition process in single head annular combustor was carried out, and characterics of flame propagation in single head annular combustorwas analyzed. According to the structure and flow features of single head annular combustor,simulation model of triple-head annular combustor was established. Transient propagation process offlame in multi-head annular was simulated and analyzed. Results show that this numerical simulationmethod can predict main combustion chamber ignition transient process better.The research results provide a theoretical foundation and technical support for combustionchamber design and engineering application.