Flame spread over solids in buoyant and forced concurrent flows: Model computations and comparison with experiments

A detailed three-dimensional concurrent flame spread model is tested and compared with three sets of experiments. The parameters varied include: gravity, flow velocity, pressure, oxygen mole fraction, and sample width. In buoyant flows (normal and partial gravities), the computed steady spread rate and flame profiles agree favorably with experiment. The predicted extinction limits are lower but can be improved. Comparison in forced concurrent flow in microgravity shows correct trends. The predicted steady spread rates are lower than the experimental ones if the flames are short but higher than the experimental ones if the flames are long. It is believed that the experimental flames may not have fully reached steady state at the end of the 5-s microgravity drops. Longer duration microgravity experiments in future will be needed to substantiate this belief.