Downward flame spread over poly(methyl)methacrylate

Bhattachariee, Subrata; King, Matthew D.; Takahashi, Shuhei; Nagumo, Takeshi; Wakai, Kazunori

doi:10.1016/s0082-0784(00)80713-4

Cited by 35 publications

(11 citation statements)

References 20 publications

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“…In addition, the XPS employed in this work is the thermally thick solid . Bhattacharjee et al proposed a formula to predict the downward flame spread rate of thermally thick solid, as shown in Equation :

V_{f, thick} ~ V_{g} \frac{λ_{g} ρ_{g} c_{p, g} {(T_{f} - T_{v})}^{2}}{λ_{s} ρ_{s} c_{p, s} {(T_{v} - T_{\infty})}^{2}} .

The weakening of the stack effect attributes to the dropping of the buoyancy‐induced airflow rate ( V g ), which is positively correlated with V f . Thus, the flame spread rate decreases as the dimensionless opening area rises.…”

Section: Resultsmentioning

confidence: 99%

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Study on downward flame spread over extruded polystyrene foam in a vertical channel: Influence of opening area

Yin

Chen

et al. 2018

Fire and Materials

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Summary Experimental methods and theoretical analysis are employed to investigate effects of channel opening area on downward flame spread characteristics of extruded polystyrene (XPS) thermal insulation materials on building facade. The average flame height first drops and then rises as dimensionless opening area (the ratio of sidewall opening area to sidewall area, ie, S*) increases. As S* rises, both the average and maximum temperature of the curtain wall decrease, and the decreasing of the average temperature is linear. XPS surface temperature history can be divided into four stages, ie, inapparent rising stage (preheating), significant rising stage (melting), dropping stage (pyrolysis), and rerising stage (ignition). The preheating length first rises and then drops as S* increases. The XPS flame spreads steadily at the early period while acceleration occurs at the later period. For different opening areas, the difference in spread distance history is not apparent in the early stage while this difference is significant in the later stage. The flame spread rate (Vf) first increases and then decreases as S* rises. A downward flame spread model for XPS in vertical channel with openings is built. The varied trend of Vf predicted using this model corresponds to the experimental result.

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V_{f, thick} ~ V_{g} \frac{λ_{g} ρ_{g} c_{p, g} {(T_{f} - T_{v})}^{2}}{λ_{s} ρ_{s} c_{p, s} {(T_{v} - T_{\infty})}^{2}} .

Section: Resultsmentioning

confidence: 99%

“…In addition, the XPS employed in this work is the thermally thick solid. [40][41][42] Bhattacharjee et al 43,44 proposed a formula to predict the downward flame spread rate of thermally thick solid, as shown in Equation 14:…”

Section: Flame Spread Process and Flame Spread Ratementioning

confidence: 99%

Study on downward flame spread over extruded polystyrene foam in a vertical channel: Influence of opening area

Yin

Chen

et al. 2018

Fire and Materials

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“…de Ris [5] developed the early significant analytical model for flame spread in a forced convection environment with an exact solution in the thick limit and an approximate solution. Bhattacharjee et al [6,7] extended the de Ris’s theory to downward spreading configuration by proposing an empirically determined equivalent buoyant convection velocity. The predictions which retain the functional form of the de Ris formula, are shown to accord well with computational and experimental results.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Thermal Behavior of Insulation Material Rigid Polyurethane in Parallel, Symmetric, and Adjacent Building Façade Constructions

Zhu

et al. 2018

Polymers

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Both experimental and theoretical methods were proposed to assess the effects of adjacent, parallel, and symmetric exterior wall structures on the combustion and flame spreading characteristics of rigid polyurethane (PUR) foam insulation. During the combustion of PUR specimens, the flame leading edge was found to transfer from a unique inverted ‘W’ shape to an inverted ‘V’ during flame propagation. This phenomenon is attributed to edge effects related to boundary layer theory. The effects of the adjacent façade angle on flame spreading rate and flame height were shown to be nonlinear, as a result of the combined influences of heat transfer, radiation angle, and the chimney restriction effects. A critical angle around 90 degree with maximum thermal hazards outwards by parallel fire was observed and consistent with the mass loss rate and flame height tendencies. For narrow spacing configurations or angles (e.g., 60 and 90 degrees), phenomenological two-pass processing in conjunction showed that increased preheating lengths were associated with enhanced heat transfer. The results of this study have implications concerning the design of safe façade structures for high-rise buildings, and provide a better understanding of downward flame spreading over PUR.

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“…2 The influence of sample thickness on flame spread over solid fuel is a fundamental study both for charring and non-charring materials. [3][4][5][6][7] As thickness increases, thermal conduction through solid phase plays an increasingly significant role in the paths of heat transfer. 8 De Ris 3 presented a formulated model of opposed flow flame spread, in which sample thickness is considered to influence the flame spread rate.…”

Section: Introductionmentioning

confidence: 99%

Width effects on downward flame spread over poly(methyl methacrylate) sheets

Zhao

Zhou

Yang

et al. 2014

Journal of Fire Sciences

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The experiments of downward flame spread over poly(methyl methacrylate) sheets with different dimensions were conducted in this study. In comparison with flame spread over samples under infinite width condition, lateral air entrainment shows significant influence on downward flame spread of finite width. The characteristic angles, defined as those produced on sample residues in a steady-state stage, are constant for different dimensions. Based on the characteristic angles and with reasonable assumptions, a three-dimensional theoretical model is proposed to illustrate the experimental results. Width effects on downward flame spread over thicker samples are more obvious and they fade away with gradual increase in width. Moreover, the heat flux penetrating through the solid surface at the front of the pyrolysis region is higher than that in the twodimensional case. The flame height correlates well with mass loss rate as an exponential function with a mean power value of 0.79.

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Downward flame spread over poly(methyl)methacrylate

Cited by 35 publications

References 20 publications

Study on downward flame spread over extruded polystyrene foam in a vertical channel: Influence of opening area

Study on downward flame spread over extruded polystyrene foam in a vertical channel: Influence of opening area

Experimental Study of Thermal Behavior of Insulation Material Rigid Polyurethane in Parallel, Symmetric, and Adjacent Building Façade Constructions

Width effects on downward flame spread over poly(methyl methacrylate) sheets

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