Opposed-flow flame spread over carbon fiber reinforced plastic under variable flow velocity and oxygen concentration: The effect of in-plane thermal isotropy and anisotropy

Kobayashi, Yoshinari; Terashima, Kaoru; Oiwa, Rikiya; Tokoro, Misuzu; Takahashi, Shuhei

doi:10.1016/j.proci.2020.06.380

Cited by 23 publications

(5 citation statements)

References 20 publications

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“…Di Blasi [22] discovered that increasing the thermal conductivity along the parallel direction of the flame spread had no impact on the flame spread velocity, but enhancing the thermal conductivity along the vertical flame spread direction increased the thermal penetration depth and decreased the flame spread rate. Similar conclusions were subsequently drawn by Kobayashi [23] based on flame spread tests of carbon-fiber-reinforced polymers. However, these conclusions were obtained from either theoretical calculations or non-charring polymer tests, which might not be valid for charring wood.…”

Section: Introductionsupporting

confidence: 83%

Influences of Species and Density on the Horizontal Flame Spread Behavior of Densified Wood

Zhou,

Qiu,

Zhou

et al. 2024

Buildings

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Densified wood possesses outstanding mechanical properties and serves as a desired construction material for modern timber buildings. However, the limited research on its flame behavior hinders its broader applications. The authors of this paper experimentally and analytically investigated the influence of wood species and density on horizontal flame spread behavior. Densified oak and densified fir were tested. The flame spread rate decreased with wood density in both densified wood types. Their values were close at the same density. The mass loss rate (m˙) of the densified wood decreased with the increase in wood density. The densified oak had higher m˙ due to its lower lignin content. Dimensionless correlations between the m˙ and density were obtained which agree with the experiments. The flame heights (Lf) of the densified wood also decreased with the increase in wood density. The densified oak had higher Lf due to its higher m˙. As the densified wood density increased, the radiation (and conduction) was reduced (and enhanced), but the convection remained constant. The densified oak had lower convection, lower conduction, and higher radiation than the densified fir at the same density. Gas-phase heat transfer was dominant in the flame spread of the densified wood, but conduction was also significant as its contribution can be as high as 70% of gaseous heat transfer.

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Section: Introductionsupporting

confidence: 83%

Influences of Species and Density on the Horizontal Flame Spread Behavior of Densified Wood

Zhou,

Qiu,

Zhou

et al. 2024

Buildings

View full text Add to dashboard Cite

show abstract

“…In other words, the orientation of the reinforcement did not affect the ROS (but there was influence from the orientation along and perpendicular to the fibers). In the case of CFRP [ 6 , 7 ], the behavior of ROS was significantly different—a significant influence of the direction in which the sample was burning was observed. This is due to the dependence of thermal conductivity on the fibers’ orientation.…”

Section: Resultsmentioning

confidence: 99%

“…Fiber reinforcement was found to influence the combustion mechanism and to act as a barrier for the heat from the flame and to prevent migration of the matrix degradation products [ 5 ]. Opposed-flow and buoyant-flow flame spread over carbon-fiber-reinforced plastic (CFRP) under variable flow velocity and oxygen concentration was investigated [ 6 , 7 ]. It was revealed that a change in the orientation of the carbon fibers caused thermal anisotropy, resulting in the differences in the values of the oxygen concentration limit and the flame spread rate [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study of Downward Flame Spread over Glass-Fiber-Reinforced Epoxy Resin

et al. 2022

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For the first time, a comprehensive study of downward flame spread over glass-fiber-reinforced epoxy resin (GFRER) slabs in oxidizer flow has been carried out experimentally and numerically. Microthermocouples were used to measure the temperature profiles on the solid fuel’s surface and in the flame, and a video camera was used to measure the rate of flame spread (ROS). The ROS was found to be linearly dependent on the oxygen concentration, to be inversely proportional to the slab thickness and not to depend on the direction of the flame spread over the slab. The absence of the influence of the forced oxidizing flow velocity and the weak influence of the GFRER pyrolysis kinetics on the ROS were observed. For the first time, a numerical model of flame spread over reinforced material with thermal conductivity anisotropy was developed on the basis of a coupled ‘gas–solid’ heat and mass transfer model, using modifications of the OpenFOAM open-source code. The sensitivity analysis of the model showed that the thermal conductivity in the normal direction to the GFRER surface had a much greater effect on the ROS than the thermal conductivity along the direction of flame propagation. The numerical results show good agreement with the experimental data on the dependences of the ROS on oxygen concentration, slab thickness and the N2/O2 mixture flow velocity, as well as temperature distributions on the fuel surface, the maximum flame temperatures and the flame zone length.

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“…However, the type of reinforcing fiber can affect the flame propagation mechanism. In contrast to carbon fiber plastics [ 77 ], in the case of glass fiber plastics (for GFRER), the ROS does not depend on the thermal conductivity along the glass–epoxy, but rather, it depends on the thermal conductivity in the direction perpendicular to the flame propagation velocity [ 67 ] ( Figure 23 ). Thermal conduction in the normal direction to the slab has a greater effect on the rate of flame spread (ROS) than along it [ 67 ].…”

Section: Combustion Mechanisms Of Pmma Pe and Gfrer Without Flame-ret...mentioning

confidence: 99%

Mechanisms of the Action of Fire-Retardants on Reducing the Flammability of Certain Classes of Polymers and Glass-Reinforced Plastics Based on the Study of Their Combustion

et al. 2022

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In the present review, using an integrated approach based on the experimental and theoretical study of the processes of thermal decomposition and combustion of practically important polymers, such as polymethyl methacrylate, polyethylene, and glass-fiber-reinforced epoxy resin, the features of the mechanism for reducing the combustibility of these materials with phosphorus-containing flame-retardants (FR), as well as graphene, are identified. A set of original experimental methods was developed and applied that make it possible to study the kinetics of thermal decomposition and the thermal and chemical structure of the flames of the studied materials, including those with FR additives, as well as to measure the flame propagation velocity, the mass burning rate, and the heat fluxes from the flame on the surface of a material. Numerical models were developed and tested to describe the key parameters of the flames of the studied polymeric materials. An analysis of the experimental and numerical simulation data presented showed that the main effect of phosphorus-containing fire-retardants on reducing the combustibility of these materials is associated with the inhibition of combustion processes in the gas phase, and the effect of adding graphene manifests itself in both gas and condensed phases.

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Opposed-flow flame spread over carbon fiber reinforced plastic under variable flow velocity and oxygen concentration: The effect of in-plane thermal isotropy and anisotropy

Cited by 23 publications

References 20 publications

Influences of Species and Density on the Horizontal Flame Spread Behavior of Densified Wood

Influences of Species and Density on the Horizontal Flame Spread Behavior of Densified Wood

Experimental and Numerical Study of Downward Flame Spread over Glass-Fiber-Reinforced Epoxy Resin

Mechanisms of the Action of Fire-Retardants on Reducing the Flammability of Certain Classes of Polymers and Glass-Reinforced Plastics Based on the Study of Their Combustion

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