Effects of fuel Lewis number on flame spread over solids

Tolejko, Kevin; Feier, Ioan I.; T’ien, James S.

doi:10.1016/j.proci.2004.08.129

Cited by 8 publications

(4 citation statements)

References 15 publications

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“…This was assumed as the exact products of pyrolysis at the surface and their diffusivities are not known, hence, the fuel Lewis number remains an unknown quantity. The effect of fuel Lewis number has been studied [26] by varying fuel Lewis number over a wide range (0.1 to 3). The flame location was reported to shift with the change in Lewis number.…”

Section: Discussionmentioning

confidence: 99%

Effect of Gas Phase Heat Sink on Suppression of Opposed Flow Flame Spread over Thin Solid Fuels in Microgravity Environment

Malhotra

Kumar

2012

Journal of Combustion

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A two-dimensional numerical model of opposed flow flame spread over thin solid fuel is formulated and modeled to study the effect of gas phase heat sink (a wire mesh placed parallel to the fuel surface) on the flame-spread rate and flame extinction. The work focuses on the performance of the wire mesh in microgravity environment at an oxygen concentration 21%. The simulations were carried out for various mesh parameters (wire diameter, "d wr " and number of wires per unit length, "N") and mesh distance perpendicular to fuel surface "Y mesh ". Simulations show that wire mesh is effective in reducing flame-spread rate when placed at distance less than flame width (which is about 1 cm). Mesh wire diameter is determined not to have major influence on heat transfer. However, smaller wire diameter is preferred for better aerodynamics and for increasing heat transfer surface area (here prescribed by parameter "N"). Flame suppression exhibits stronger dependence on number of wires per unit length; however, it is relatively insensitive to number of wires per unit length beyond certain value (here 20 cm −1).

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Section: Discussionmentioning

confidence: 99%

Effect of Gas Phase Heat Sink on Suppression of Opposed Flow Flame Spread over Thin Solid Fuels in Microgravity Environment

Malhotra

Kumar

2012

Journal of Combustion

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“…However, for the hydrogen, the larger effect is observed. Since the deficient reactant is fuel in lean premixed mixture, it is important to consider the Lewis number (Le = K/D), where K is the thermal diffusivity and D is the diffusion coefficient [14,28]. It is well known that, roughly Le = 1 for lean methane/air mixture, Le > 1 for lean propane/air mixture, and Le < 1 for lean hydrogen/air mixture.…”

Section: Discussionmentioning

confidence: 99%

“…The phenomena of flame spread are therefore complex process. So far, many studies on the flame spread over inflammable solids have been performed, often using samples such as filter papers and polymethyl methacrylate (PMMA) materials to simulate the flame spread in fire [9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Flame structure and flame spread rate over a solid fuel in partially premixed atmospheres

Yamamoto

Ogata

Yamashita

2011

Proceedings of the Combustion Institute

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“…Predictions of fire growth and spread rely heavily on the understanding of fire spread mechanisms on solid fuels. A number of researchers, including Wichman [2], Fernandez-Pello [2][3][4][5][6][7], Tolejko [8], T'ien [8,9], and Dl Blasi [10,11], have made contributions to the study of counterflow fire spread on solid fuels. These researchers have simplified heat transfer and flow models in the flame spread process and studied the effect of parameters such as the Lewis number and wind speed on the flame spread.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Downward Flame Propagation in Discontinuous Region of Solid Fuel

Zhu

Luo

Zhao

et al. 2023

Fire

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This paper presents a numerical model that investigates the characteristics of flow, heat, and mass transfer on downward flame propagation in the discontinuous region of solid fuel. Simulations were carried out for various discontinuous distances to analyze the morphology of the flame front and the competition between the “jump” of flame spread and heat transfer from the flame to the unburned area. The results demonstrate that there is a “jump” in the flame propagation in the discontinuous zone, with the flame front exhibiting a defined “acute angle” that undergoes a process from large to small during the flame spreading in the discontinuous area and deflects towards the discontinuous area of the material. The temperature in the discontinuous zone reaches a peak, and the average flame spread rate initially increases and then decreases with the increase of discontinuity distance until the flame spread stops. The study provides valuable insights into the growth and development of fires involving discretely distributed combustible materials.

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Effects of fuel Lewis number on flame spread over solids

Cited by 8 publications

References 15 publications

Effect of Gas Phase Heat Sink on Suppression of Opposed Flow Flame Spread over Thin Solid Fuels in Microgravity Environment

Effect of Gas Phase Heat Sink on Suppression of Opposed Flow Flame Spread over Thin Solid Fuels in Microgravity Environment

Flame structure and flame spread rate over a solid fuel in partially premixed atmospheres

Numerical Simulation of Downward Flame Propagation in Discontinuous Region of Solid Fuel

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