Radiation Modeling of a Hydrogen Fueled Scramjet

With the difficulty and cost of full-scale flight experiments, the design of scramjet engines relies heavily on computational simulations. Radiation may play an important role in the wall heating and flow cooling of scramjets. However, very few studies have focused on such. The present analysis is based on three-dimensional turbulent reacting flow simulations of the HyShot II hydrogen fueled scramjet engine running at flight conditions of Mach 7.4. A three-dimensional discrete ordinates method analysis with a narrowband averaged spectral model is employed to determine wall heating and flow cooling from thermal radiation. The discrete ordinates method is verified against a three-dimensional ray tracing method. The radiative species considered are H2O and OH. The radiative heat flux is on the order of 10 kW∕m2, which is 0.1–0.6% of the total convective wall heat flux. Flow cooling due to radiation is found to be on the order of 3 K. Sensitivity analysis shows that radiation is highly dependent on chamber size, temperature, pressure, and radiative species mole fraction. Variations in these factors can explain the differences between previous analyses in the literature that studied hypothetical engines and the current work that models an existing scramjet.