Impact of Fuel Type on Toxic Emissions from a Non-premixed Boundary Layer Laminar Flame in Microgravity – A Numerical Study

Examples from non-premixed boundary combustion representative of fire in microgravity environment are presented. A low forced flow 0.25 m/s is present, which typical air circulation speeds a spacecraft. The numerical simulations have been conducted to evaluate the modes heat transfer with an emphasis on discussion about effects various fuels chemical emissions such as soot, CO, CO2 and unburnt hydrocarbons reduced-gravity conditions. Typically, evaporation temperature smaller for heptane than dodecane, thus lengthening flame seems more pronounced compared that dodecane increase visible zone by factor 2.3 times. rapid regression rate due enhanced feedback contributes additional energy 80% release dodecane. In all cases, only 15% generated exothermic reaction supplied pyrolysis surface, large portion convected forward gas flow. CO molar fraction reaches maximum 11% 8% other ethylene, propane, propylene heptane. mean value concentration depends mainly fuel injection rate, appears practically insensitive oxidizer velocity. Dodecane longer carbon chain produces less propane propylene. existence toxic even size because absence natural convection has important considerations spacecraft safety smoke/gas incapacitation.