Dynamic combustion characteristics of solid fuel ramjet engine based on transient solid fuel regression simulations

The dynamic regression process of solid fuel in solid-fuel ramjets (SFRJ) is critical to combustion efficiency. However, its strong coupling with flow and heat transfer renders accurate prediction and simulation a persistent challenge. In this work, a two-dimensional transient numerical simulation model considering the heat transfer decomposition and dynamic combustion process of solid fuels was constructed, and the reliability of the model was validated through optical-access slab burner experiments enabling direct visualization of the regression process. After this, the influence of inlet gas parameters on the combustion characteristics of solid fuel ramjet was studied. The results show that the simulation model can accurately simulate the dynamic combustion characteristics of SFRJ and the regression characteristics of solid fuels. The simulation results show that the low temperature region generated in the recirculation zone leads to a significantly higher oxygen-fuel ratio in the recirculation zone than in other zones. In addition, increasing the inlet temperature and pressure will increase the fuel surface temperature, which will increase the fuel regression rate, but the increase in temperature will also increase the combustion efficiency (from 77 % to 92 %), and conversely, increasing the total intake air pressure will reduce the combustion efficiency, it was reduced by 10 %.