Wind effects on transition and extension characteristics of the external flame projecting from a compartment with opposing openings. (March 2021)

• Record Type: Journal Article
• Authors: Li, Man; Gao, Zihe; Ji, Jie; Wan, Huaxian
• Is Part Of: Fire safety journal. Volume 120(2021)
• Publication Date: 2021-03
• Subjects: Compartment fires -- External wind -- Transition criteria -- Flame length -- Maximum temperature profile; Fire prevention -- Periodicals; Incendies -- Prévention -- Recherche -- Périodiques; Fire prevention -- Research; Periodicals; 628.92205
• DOI: 10.1016/j.firesaf.2020.103102
• Languages: English
• ISSNs: 0379-7112

Abstract

Abstract: The assisting wind force effect on the transition and extension characteristics of the flame projecting outside the window of a compartment was experimentally investigated. The transition criteria, length, and maximum temperature profile of the external flame were studied. As the wind velocity increases, three states: namely a spill-like plume, horizontally ejected flame and no flame outside the window were identified in the experiments. The Froude number can be used to determine the three states of the external flames, with the critical values separating these stages being 2.3 and 6.4. Two length scales, l 1 and l 2 are proposed to modify the developed theories without a wind effect. The length scales are used to analyze the length and maximum temperature profile of the external flame. The dimensionless flame lengths are proportional to the 1.5 and 1.2 power of the dimensionless convective heat flow rate for the spill-like plume and horizontally ejected flame respectively. Correlations for the maximum temperature rises of the external flame are established between the dimensionless convective heat flow rate and the length (height) of the plume by taking into account the thermodynamic and dynamic effects of the external wind. Highlights: Fr could be used to determine the three states of the external flames. l 1 and l 2 were proposed to modify the developed theories without a wind effect. Flame lengths for the spill-like plume and horizontally ejected flame were analyzed. Correlations for the maximum Δ T of the external flames were established.