Upward flame spread on a vertically oriented fuel surface: The effect of finite width

Rangwala, Ali S.; Buckley, Steven G.; Torero, José L.

doi:10.1016/j.proci.2006.07.235

Cited by 102 publications

(63 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Non-uniform spreading may lead to an inaccurate estimation of the location of the pyrolysis front. In order to promote a more uniform spread rate, a fuel width (20 cm) was selected based on the recommendations of previous researchers [25,27]. Later analysis, detailed in Section 4.3, indicates that the pyrolysis front maintained the same basic U-shape during all tests.…”

Section: Assumptions and Sources Of Experimental Errormentioning

confidence: 99%

Upward flame spread over discrete fuels

Miller

Gollner

2015

Fire Safety Journal

View full text Add to dashboard Cite

Upward flame spread over discrete fuels has been analyzed through experimental research on vertical arrays of alternating lengths of PMMA and insulation. By manipulating the lengths of the PMMA fuel and the insulation, several important trends related to flame spread were identified and assessed.The peak flame spread rate for arrays with 4 cm lengths of PMMA occurred at a fuel percentage of 67%; for arrays with 8 cm PMMA, a peak flame spread rate occurred at fuel percentages of 67%, 80%, and 89%. It has been hypothesized that increased air entrainment at these fuel percentages maximizes the flame spread rate.Based on observed trends, this study proposed a method for approximation of the fuel spread rate at various fuel percentages. Given reasonable estimates for the homogeneous flame spread rate and the lowest fuel percentage that sustains spread, an estimation for intermediate spread rate values is feasible.

show abstract

Section: Assumptions and Sources Of Experimental Errormentioning

confidence: 99%

Upward flame spread over discrete fuels

Miller

Gollner

2015

Fire Safety Journal

View full text Add to dashboard Cite

show abstract

“…For horizontal flame spread, Li et al [3] demonstrated that flame spread rate increased with a rise in sample width, while Mell et al [4] concluded that the reverse is true. Rangwala et al [5] and Pizzo et al [6] attributed width effects to heat diffusion by sample sides. However, Mell et al [4] hypothesized that these phenomena were caused by the convective heat transfer variation due to a change in width.…”

Section: Introductionmentioning

confidence: 99%

Effects of Sample Width and Sidewalls on Downward Flame Spread over XPS Slabs

An¹,

Xiao²,

Sun³

et al. 2014

Fire Saf. Sci.

View full text Add to dashboard Cite

To study the effects of sample width and sidewalls on downward flame spread over extruded polystyrene (XPS) slabs, a series of laboratory-scale experiments were conducted. Flame shape, flame spread rate, mass loss rate and temperature were recorded. For XPS without sidewalls, the average maximum flame height (H) and average flame area per unit of width (A/w) rise linearly with an increase in sample width (w) and mass loss rate per unit of width. When sidewalls are absent, flame spread rate first drops and then rises with an increase in width. This trend is determined by gas-phase heat transfer. When sidewalls are present, flame spread rate increases with a rise in width, and solid-phase heat conduction determines the trend. Sidewall effects are comprised of four aspects: oxygen concentration near the sidewalls and gypsum board is low, which leads to reduced flame heat flux; upward and front air flow is intensified; the flame is stretched, and the surface flame is weakened; and molten XPS mass decreases. For narrow samples, H and A/w with sidewalls are higher than those without sidewalls, while the reverse was observed in wider samples. The mass loss rate, preheating length and average flame spread rate with sidewalls are smaller than those obtained without sidewalls. Flame spread acceleration with sidewalls occurs at a broader width than that without sidewalls. The experimental results agree well with the theoretical analysis.

show abstract

“…Using the theory developed by Pagni and Shih [25], the excess pyrolyzate can be determined. The excess pyrolyzate depends on the B-number; recent work published by the authors' shows that the excess pyrolyzate is also a function of the width of the fuel [43]. Assuming that all the excess pyrolyzate is burned upstream, a flame length can then be obtained.…”

Section: Evolution Of the B-number With Timementioning

confidence: 99%

Flame Spread Analysis Using a Variable B-Number

Rangwala¹

2008

Fire Saf. Sci.

View full text Add to dashboard Cite

Flame spread over solid materials is commonly described in the literature by a two-dimensional reactive boundary layer solution first formulated by Emmons (1956). In the recent past, experimental measurements associated with material flammability testing (e.g. NASA-STD-6001) are compared with the Emmons solution, as modified by Pagni and Shih (1979), and found in disagreement. In the classical solution, the B-number (Spalding mass transfer number) appears as one of the boundary conditions, and has been traditionally assumed a constant for mathematical simplicity. However, experimental results show that the B-number is not a constant, but varies with time and space. A simple modification to the standard measurement procedure is described, which allows calculation of the B-number from the flame stand-off distance. Measurements of flame standoff distance are performed to determine the B-number as a function of time. The classical combustion problem is revisited to model flame spread over a combustible surface. An experimentally-obtained B-number is used to model flame propagation, showing good agreement with current and previous experimental data obtained from the literature. Implications to microgravity flame spread are discussed.

show abstract

Upward flame spread on a vertically oriented fuel surface: The effect of finite width

Cited by 102 publications

References 19 publications

Upward flame spread over discrete fuels

Upward flame spread over discrete fuels

Effects of Sample Width and Sidewalls on Downward Flame Spread over XPS Slabs

Flame Spread Analysis Using a Variable B-Number

Contact Info

Product

Resources

About