Performance Investigation Of Rocket-based Combined Cycle Ejector/Ramjet Mode Under SMC Combustion Orgnization Mode

SMC mode is one of typical combustion organization modes for RBCC engine in which combustion efficiency is low but the length of combustor and the weight of structure are reduced.Therefore it's significant to study SMC mode for increasing the performance of RBCC engine.Being a basal research technique,theoretical analysis can make physical conceptions clear and the laws of physics concise.So it's feasible to study SMC mode by quasi-one-dimensional analysis.Qusai-one-dimensional analysis of SMC combustion organization method of ejector/ramjet modes for RBCC engine was carried out.Physical and mathematical models fit for SMC mode were built.Then analysis of influence factor to ejector mode properties for RBCC engine under SMC mode was carried out.Finally,theoretical results with the nozzle and without the nozzle were verified by the CFD method.Therefore some guides for combustion organization of RBCC engine can be provided.Firstly physical and mathematical models fit for SMC mode of contractive RBCC engine under sea level and static state were built.Then theoretical analysis of ejector without combustion,SMC mode and influence factor to ejector mode properties for RBCC engine were carried out in order.Also,the derivation processes of important equations and results for three parts were respectively given.So the creditability of theoretical models was testified by analyzing theoretical results.Then on the base of the above models,physical and mathematical models fit for SMC mode of divergent RBCC engine under different high altitudes and high flight Mach numbers were built by making large changes.According to two kinds of wall pressure distributions,analysis of influence factor to properties including flight states,ejector rocket and configuration was conducted.Results indicated,conclusions this paper drew were widely fit for SMC mode,and influence of performance for RBCC engine wall pressure distributions exerted on was small.Last investigation of performance for RBCC ejector/ramjet modes was conducted by using CFD method.The main intention was to testify the creditability of theoretical models for SMC mode under different high altitudes and high flight Mach numbers.Validation was developed in the light of different influence factors including flight states,ejector rocket and configuration.The content of validation concludes combustor outlet parameters for non-nozzle conditions,RBCC thrust and nozzle outlet parameters for conditions with nozzles.Results indicated,there were some differences between theoretical and numerical results,but the variation trend was coherent.Therefore CFD methods proved the creditability of theoretical models to some degree.