Numerical investigation of combustion flammability characteristics in solid fuel scramjet combustor

The unsteady combustion of polymethylmethacrylate in solid fuel scramjet (SFSCRJ) combustor has been simulated numerically based on dynamic grid technology. A solid fuel combustion numerical model is established based on coupling of heat transfer and mass injection in supersonic flow. The effects of combustor shape and inlet total temperature on combustion characteristics of PMMA have been studied. The results show that the numerical model is proved to be effective by comparing with the measured values. Self-ignition pressurization and sustained combustion could be permitted in SFSCRJ combustor. During the process of combustion, the cavity becomes more and more narrow due to the uneven distribution of regression rate of fuel grain. The flame-holding capability reduces with the increase of the main flow velocity and the broaden of fuel port leading to the occurrence of flameout. A relatively deep cavity and relatively high inlet total temperature are helpful to sustain combustion. Both the working time and fuel consumption increase by 1.8 times when inlet total temperature increases by 400 K.