Numerical investigation on effects of injection mode on supersonic combustion of kerosene

In order to optimize fuel injection system in a scramjet engine and improve combustion characteristics and engine reliability, three-dimensional numerical investigation on supersonic combustion of liquid kerosene in different injection modes based on staged-cavities module has been carried out. It is analyzed that wall injection and loop injection have some influence upon the combustor performance. Static pressure predicted by numerical method is compared with experimental data. The results show that loop injection improves mixing characteristics through uniform distribution of fuel in the combustor. Hence, the combustor efficiency of loop injection increased by 4.36% compared with wall injection. The total pressure loss of the two injection modes along the combustor length is almost the same and it loses 50% in the combustor outlet. At the downstream of the second injection ports, range of CO₂ from loop injection is bigger and more uniform than that of wall injection, which indicates that the former can enhance combustion. However, the penetration depth of loop injection is lower than that of wall injection due to small dynamic pressure ratio for the former. In general, it is suggested that wall injection should be chosen to simplify fuel injection system and increase engine reliability at the same fuel equivalence ratio.