One important measure of material fire hazard is the flame height a given polymer produces upon burning in a specified ambience. Six systems are considered here—two fuel geometries: wall-mounted and free standing; and three flow fields: forced, free and mixed-mode. In each case, the extent of the combusting gas downstream of a pyrolyzing slab is obtained as a function of the fuel’s thermochemical properties. The flow is modeled as a steady, laminar, two-dimensional, nonradiative boundary layer. The combustion is described by a single Shvab-Zeldovich energy-species equation assuming unit Lewis number and a fast one-step overall gas phase reaction. Numerical methods are employed due to the abrupt change in boundary conditions at the end of the pyrolyzing slab. However, an approximate similarity solution is found for forced flow which yields explicit flame heights. Based on these results, explicit functional fits to numerical flame heights are obtained for free and mixed-mode flows. Comparisons between theory and experiment indicate quantitative agreement.

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