Computational and experimental study of ammonium perchlorate/ethylene counterflow diffusion flames

We investigated the modeling of counterflow diffusion flames in which the products of ammonium perchlorate (AP) combustion were counterflowed against an ethylene fuel stream. The two-dimensional problem can be reduced to a one-dimensional boundary value problem along the stagnation point streamline through the introduction of a similarity transformation. By utilizing recent developments in hydrocarbon, chlorine, NO_x and AP kinetics, we formulated a detailed transport, finite-rate chemistry system for the temperature, velocity, and species mass fractions of the combined flame system. A detailed soot model is included which can predict soot volume fractions as a function of the strain rate and the fuel mole fraction. We compare the results of this model with a series of experimental measurements in which the temperature was measured with radiation-corrected thermocouples and OH rotational population distribution; several important species were measured with planar laser-induced fluorescence, UV-visible absorption, and Raman spectroscopies; and the soot volume fraction was measured with laser-induced incandescence and visible absorption spectroscopy.