Fire Safety Science Digital Archive

Merging behavior of flames from two rectangular fire sources (2cm x 80cm, and 2cm x 40cm) in parallel configuration was studied theoretically and experimentally. Propane gas, as a fuel, gave 9.5 - 57 kW per unit length. Height of flame merging started, Lm, was estimated based on the vertical and horizontal distributions of temperature and upward velocity. Lm showed linear dependence on the separation, S, between two parallel fire sources and not on the heat release rates. Dimensionless merging height, S/Lm, is expressed as a coupled function of dimensionless heat release rate Qrec, Froude Number, and separation factor of (1-W/2S). Merged and/or inclined flame tip heights consist of two flames, Lfm, were estimated based on visual data which decreased as separation distance increased with the correction factor of ((S2+2DW)/2(S2+D)) 2/3, where D and W are shorter and longer length of a rectangular burner.