Abstract: The wider the substrate of liquid fuel leakage and diffusion, the longer the unconfined multi-directional spreading process of the flowing fire, which increases its hazard. To investigate the effect of substrate width on the combustion characteristics of flowing fire such as diffusion combustion area and burning rate, a series of continuous leakage ethanol flowing fire tests were conducted. Five leakage rates (30, 50, 70, 90, 110 L/min) were set, and the width of the glass substrate of the rectangular flow channel was varied (0.05, 0.10, 0.15, 0.20, 0.25, 0.30 m). The results show that for the same leakage rate, the stable combustion area and maximum combustion area increase with increasing width, and this increasing trend is more pronounced at higher leakage rates. The heat loss of the fuel layer increases with the width of the substrate, leading to a decrease in the burning rate. Comparison of dimensionless burning rate models reveals that the burning rate of ethanol flowing fire on the glass substrate is higher than that on the steel substrate.

Key words: flowing fire, substrate width, combustion area, burning rate