Experimental investigation on morphology of window-ejected flame without facade effect

As the key characteristic of window-ejected flames, flame morphology such as flame height, flame depth involves the ignition of surrounding buildings. This article experimentally investigated the flame height, the maximum flame width and the maximum flame depth ejected from a fire compartment without the facade wall effect. A small-scale compartment with a sidewall opening attached to compartment top is used for simulating the situation without the facade wall. The ejected flame height, maximum flame width and maximum flame depth were recorded and measured for various opening sizes and fuel supply rates. Results show that: (1) The ejected flame height increases as the increase of fuel supply rate and decreases as the increase of opening dimension, and was obviously lower than that with the facade effect; (2) The maximum flame width increases as the increase of fuel supply rate and decreases with the increase of opening dimension, and was higher than that with the facade effect; (3) The maximum flame depth increases as the increase of fuel supply rate, and the formation of maximum flame depth was analyzed based on the ejected thermal plume momentum and the air entrainment momentum. A dimensionless parameter, which presents the complex competition mechanism between the plume momentum and the air entrainment momentum, was proposed to characterize their impacts on flame depth, by which the maximum flame depth was represented well. This work would provide theoretical support for building fire prevention and control.