Computer Modelling of a Plane Flame Furnace Firing Low Volatile Fuels

Abstract

A computer model of a plane flame furnace firing low volatile fuels has been modelled as a one dimensional flow problem between plane-parallel boundaries. The dominant element of the model is the radiation flux, with reaction included by adoption of experimental data for char particles cited in the literature (Field, 1969), modified by inclusion of a “reactivity” parameter, β that takes values from unity to zero. The objective of the modelling was to explain otherwise anomalous experimental values of ignition distance (50 cm) of low reactivity, low-volatile fuels (Cogoli et al., 1977) that simple radiation theory (Essenhigh and Csaba, 1963) could not account for although it did account for the ignition distance (5 cm) of high reactivity fuels. The more complete model described in this paper did account for ignition distances up to 50 cm with flame lengths and temperatures reasonably comparable to those found experimentally, when the reactivity parameter lay between 0.5 and 0.1. The results show that ignition distances are appreciatively sensitive to fuel reactivity although ignition temperatures, defined as the 1 percent combustion point, are not