Effects of gas-phase radiation and detailed kinetics on the burning and extinction of a solid fuel

This is the first attempt to analyze both radiation and detailed kinetics on the burning and extinction of a solid fuel in a stagnation-point diffusion flame. A detailed and comparatively accurate computational model of a solid fuel flame is presented along with a quantitative study of the kinetics mechanism, radiation interactions, and the extinction limits of the flame.; A detailed kinetics model for the burning of solid trioxane (a trimer of formaldehyde) is coupled with a narrow-band radiation model, with carbon dioxide, carbon monoxide, and water vapor as the gas phase participating media. The solution of the solid trioxane diffusion flame over the flammable regime is presented in some detail, as this is the first solution of a heterogeneous trioxane flame. High temperature and low temperature reaction paths are identified for the heterogeneous trioxane flame.; The adiabatic solution is then compared to solutions that include surface radiation only and gas phase and surface radiation using a black surface model. The analysis includes discussion of detailed flame chemistry over the flammable regime, and in particular at the low stretch extinction limit. Emphasis is given to the low-stretch regime of the radiatively participating flame, since this is the region representative of micro-gravity flames. When only surface radiation is included, two extinction limits exist (the blow-off limit, and the low stretch radiative limit), and the burning rate and maximum flame temperatures are lower, as expected. With the inclusion of surface and gas-phase radiation, results show that while flame temperatures are lower, the burning rate of the trioxane diffusion flame may actually increase at low stretch rate due to radiative feedback from the flame to the surface.; The trioxane diffusion flame model is then extended to include surface absorption of radicals from the gas phase. The results are compared to the inert surface case. Surface radiation is also included both with and without surface radical interactions. Results indicate that for the model studied, surface absorption of radicals from the gas phase is unimportant.