Fire Safety Science Digital Archive

The characteristics and heat transfer mechanisms of flame spread along vertical comer walls have been studied experimentally. An infrared (IR) imaging system was applied to measure 8 the pyrolysis height during flame spread. The total incident heat flux to the wall surface from the flame was measured by Gardon-type heat flux meters. Flame height was recorded by a video camera. Based on these experimental studies and literature review, two important I correlations have been found for both vertical flat wall and comer wall flame spread: (1) Flame heights are primarily proportional to the elapsed time to the power of 1.3, even for the flame on the corner wall which is almost twice higher than the flame on the flat wall. (2) Heat flux correlates with the normalized height x/xf as a power law relation with the exponent 1 of -2.3 in preheat zone. Based on these two correlations, the transient heat flux distribution 1 in preheat zone has been modeled as an exponential function of time and height. Introducing the heat flux model into the one-dimensional heat transfer model for preheating process, an empirical flame spread model has been developed, and verified by experimental results.