The Study On Characteristics Of Ejecting And Combustion In RBCC Engine

The complex flow and combustion characteristics in RBCC ejector mode are urgently needed to be settled.The current study focuses on the RBCC ejector mode and investigates the ejecting and combustion characteristics in a combustor-liked confined space experimentally and numerically.The effect of the total pressures of the primary flow on the performance of the ejector was studied experimentally.It was found that the secondary flow mass flow rate increased with the increasing of the total pressure of the primary flow,but the overall entrainment ratio decreased gradually.Besides,the effect of the total temperature of the primary flow on the entrainment ratio was investigated.It is found that under a constant mass flow rate of the primary flow,the increasing of the total temperature is beneficial for increasing the entrainment ratio,which is dominant,comparing to the increasing of the total pressure which can decrease the entrainment ratio.The influence of the configuration of the ejector configuration on the entrainment ratio has also been studied.It was found that in the process of narrowing the minimum section of the throat section,the entrainment ratio was increased first and then decreased.The flow and combustion mechanism in the RBCC ejector mode is investigated by studying the ejecting-combustion characteristics in a confined space experimentally and numerically.The experimental results show that the distance H between the confined space and the burner plate has a significant effect on the flame constructions in the confined space,and it is found that the combustion enhancement effect is obvious under a certain condition.Numerical study found that a secondary combustion occurs in the confined space under high Mach number conditions of the central jet.The flow and combustion characteristics and thrust performance in different combustor configurations were studied numerically.It is shown that under the condition of low flight Mach number in ejector mode,the converging-diverging configuration is more likely to produce secondary flow blocking effect.Under high flight Mach number in ejector mode,compared with other configurations,the converging-diverging configuration can significantly improve the total heat release and combustion chamber thrust.The configuration is further optimized.It is found that changing in the converging angle has no significant effect on the total heat release and thrust performance.The increasing of the contraction ratio increases the total heat release.The thrust performance is optimal when the contraction ratio is 6.5%.