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Journal ArticleDOI

Mechanisms of fire spread

01 Jan 1977-Vol. 16, Iss: 1, pp 1281-1294
TL;DR: In this paper, the authors provide a framework within which various studies can be placed, focusing on the underlying heat-transfer, fluid-flow and chemical-kinetic phenomena of fire spread.
Abstract: Mechanisms involved in many types of fire spread are described in a manner that sacrifices accuracy for the purpose of emphasizing general aspects of the underlying heat-transfer, fluid-flow and chemical-kinetic phenomena. Consideration is given to conditions for transition from one mode of propagation to another. Research on fire spread has been pursued intensively in recent years, and in the present contribution at attempt is made to provide a framework within which various studies can be placed. Entries to current literature are provided. Areas of apparent importance that do not seem to have been emphasized are suggested.
Citations
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Journal ArticleDOI
TL;DR: In this paper, an extensive literature review conducted within Edinburgh University's Fire Safety Engineering Group and sponsored by the UK Home Office Fire Research and Development Group was conducted to establish the current state-of-the-art regarding the use of water sprays for the suppression and extinguishment of typical (Class ‘A) compartment fires and to identify where gaps exist in the current knowledge.

411 citations

Journal ArticleDOI
TL;DR: In this article, the authors focus on the latest fire-safety issues of EVs related to thermal runaway and fire in Li-ion batteries and provide a qualitative understanding of the fire risk and hazards associated with battery powered EVs.
Abstract: Over the last decade, the electric vehicle (EV) has significantly changed the car industry globally, driven by the fast development of Li-ion battery technology. However, the fire risk and hazard associated with this type of high-energy battery has become a major safety concern for EVs. This review focuses on the latest fire-safety issues of EVs related to thermal runaway and fire in Li-ion batteries. Thermal runaway or fire can occur as a result of extreme abuse conditions that may be the result of the faulty operation or traffic accidents. Failure of the battery may then be accompanied by the release of toxic gas, fire, jet flames, and explosion. This paper is devoted to reviewing the battery fire in battery EVs, hybrid EVs, and electric buses to provide a qualitative understanding of the fire risk and hazards associated with battery powered EVs. In addition, important battery fire characteristics involved in various EV fire scenarios, obtained through testing, are analysed. The tested peak heat release rate (PHHR in MW) varies with the energy capacity of LIBs ($$E_{B}$$ in Wh) crossing different scales as $$PHRR = 2E_{B}^{0.6}$$. For the full-scale EV fire test, limited data have revealed that the heat release and hazard of an EV fire are comparable to that of a fossil-fuelled vehicle fire. Once the onboard battery involved in fire, there is a greater difficulty in suppressing EV fires, because the burning battery pack inside is inaccessible to externally applied suppressant and can re-ignite without sufficient cooling. As a result, an excessive amount of suppression agent is needed to cool the battery, extinguish the fire, and prevent reignition. By addressing these concerns, this review aims to aid researchers and industries working with batteries, EVs and fire safety engineering, to encourage active research collaborations, and attract future research and development on improving the overall safety of future EVs. Only then will society achieve the same comfort level for EVs as they have for conventional vehicles.

303 citations

Journal ArticleDOI
TL;DR: In this paper, heat transfer and gas phase chemical kinetic aspects of the flame spread process are addressed separately for the spread of flames in oxidizing flows that oppose or concur with the direction of propagation.
Abstract: Recent advances in the experimental study of the mechanisms controlling the spread of flames over the surface of combustible solids are summarized in this work. The heat transfer and gas phase chemical kinetic aspects of the flame spread process are addressed separately for the spread of flames in oxidizing flows that oppose or concur with the direction of propagation. The realization that, in most practical situations, the spread of fire in opposed gas flows occurs at near extinction or non-propagating conditions is particularly significant. Under these circumstances, gas phase chemical kinetics plays a critical role and it must be considered if realistic descriptions of the flame spread process are attempted. In the concurrent mode of flame spread, heat transfer from the flame to the unburnt fuel appears to be the primary controlling mechanism. Although gas phase chemcial kinetics is unimportant in the flame spreading process, it is important in the establishment and extension of the diffusion ...

266 citations

Journal ArticleDOI
TL;DR: A review of recent progress in understanding turbulent, lifted hydrocarbon jet flames and the conditions under which they stabilize can be found in this paper, focusing on experimental results and the physically based theories that have emerged from their interpretations, as well as from the theoretically founded notions that have been supported.

248 citations


Cites background or result from "Mechanisms of fire spread"

  • ...While appearing quite different, diffusion flame stabilization in nonpremixed jets may have much in common with flame spread across liquid fuel pools and solid combustibles [16]....

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  • ...Just as it is discussed [16] that flame spread in general can be represented as lean-limit phenomena (flame spread over fuel pool), possibly lean regions in lifted jet flames may serve a similar role, especially with the recent results reported higher than previously presumed velocities witnesses in lean regions of combustion of stratified mixtures [100]....

    [...]

Journal ArticleDOI
TL;DR: A review of the essential ingredients needed to make a mathematical model of fire spread through a fuel bed is given in this article, where a unified mathematical treatment is presented, which permits a more objective comparison of the different physical models.

205 citations

References
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28 Oct 2017
TL;DR: In this paper, a mathematical model for predicting rate of fire spread and intensity applicable to a wide range of wildland fuels is presented from the conceptual stage through evaluation and demonstration of results to hypothetical fuel models.
Abstract: The development of a mathematical model for predicting rate of fire spread and intensity applicable to a wide range of wildland fuels is presented from the conceptual stage through evaluation and demonstration of results to hypothetical fuel models. The model was developed for and is now being used as a basis for appraising fire spread and intensity in the National FireDanger Rating System. The initial work was done using fuel arrays composed of uniform size particles. Three fuel sizes were tested over a wide range of bulk densities. These were 0.026-inch-square cut excelsior, 114-inch sticks, and 112-inch sticks. The problem of mixed fuel sizes was then resolved by weighting the various particle sizes that compose actual fuel arrays by either surface area or loading, depending upon the feature of the fire being predicted. The model is complete in the sense that no prior knowledge of a fuel's burning characteristics is required. All that is necessary are inputs describing the physical and chemical makeup of the fuel and the environmental conditions in which it is expected to burn. Inputs include fuel loading, fuel depth, fuel particle surface-area-to-volume ratio, fuel particle heat content, fuel particle moisture and mineral content, and the moisture content at which extinction can be expected. Environmental inputs are mean wind velocity and slope of terrain. For heterogeneous mixtures, the fuel properties are entered for each particle size. The model as originally conceived was for dead fuels in a uniform stratum contiguous to the ground, such as litter or grass. I t has been found to be useful, however, for fuels ranging from pine needle litter to heavy logging slash and for California brush fields. The concept of fuel models is introduced, wherein parameters of wildland fuels necessary for inputs to the model are categbrized and tabulated. These are then used to predict fire spread and intensity; this eliminates the necessity for repeatedly measuring such parameters. The conceptual approach recognizes that fuels have inherent characteristics that are repeatable.

1,907 citations

Journal ArticleDOI
TL;DR: In this article, the propagation of smouldering inside dust deposits, following ignition at or near the base of the deposits, was studied with several dusts in layers up to 85 cm in depth.

125 citations

Journal ArticleDOI
TL;DR: In this paper, a theory for predicting the steady rate of spread of a flame over the surface of a solid in directions ranging from downward to horizontal is developed. But the model is based on a diffusion flame in a boundary layer downstream from a point of flame inception, heat transfer by natural convection from this flame to the gasifying fuel which supports it, heat conduction through the solid to the cooler fuel ahead of the flame, generation of an upstream boundary layer due to entrainment into the flame plume, upstream gasification and diffusion of fuel into this boundary layer,

104 citations

Journal ArticleDOI
TL;DR: The physical mechanism of smoking smouldering has been studied with a view to elucidating the dependence of temperatures, consumption rates, etc., upon cigarette structure and smoking parameters as mentioned in this paper.

99 citations

Journal ArticleDOI
TL;DR: In this paper, a mathematical formulation and a method of solution for the phenomenon of flame spread over solid fuels with forward heat conduction in both the solid and the gas is presented, using an energy integral over the field to determine the spreading rate in terms of the basic properties of the fuel and air.
Abstract: Mathematical descriptions of flames spreading over liquid and solid fuels are obtained, using basic assumptions derived from observations or physical reasoning. A review of existing theories shows that they are incomplete in that they either treat an uncoupled problem of the condensed phase where the spreading rate and heat flux at the surface are given, or they merely determine the spreading rate in terms of a new vaguely defined eigenvalue. An important difference between the liquid and solid cases, due to convection, is pointed out, and it is shown that solid-fuel flame-spread theories which claim to apply to the liquid case, in reality do not apply to it. A mathematical formulation and a method of solution are presented for the phenomenon of flame spread over solid fuels with forward heat conduction in both the solid and the gas. The method uses an energy integral over the field to determine the spreading rate in terms of the basic properties of the fuel and air.

94 citations