Analysis of the Radiation Effects from Reacting Metal Particles in Counterflow Diffusion Flame using a Eulerian Lagrangian Numerical Simulation*

The radiation effects from reacting metal particles plays an important role in amplifying the regression rate of fuels in a solid fuel ramjet. A highly simplified configuration of the diffusion flame structure within a solid fuel ramjet is studied using a counterflow diffusion flame structure. The radiation transport equation is solved numerically using the filtered spherical harmonics method. The rate at which aluminum particles are inputted into the numerical simulation depends on the fuel recession rate and the particle number density in the solid fuel. The location and temperature of the particles are tracked using the Lagrangian equations of motion. A simplified model of combustion of aluminum particles and a two-equation soot model is also implemented to accurately quantify the radiation effects. The radiation effects are coupled with the hydrodynamic solver using a source term in the energy equation. Different 1D and 2D numerical simulations of the counterflow flame structure are performed and validated with existing experimental databases. We quantify the differences in the flame structure in a counterflow diffusion flame with and without radiation. A preliminary 2D numerical analysis of the diffusion flame with a solid fuel combustion chamber is also performed.