Validating Thermal Response Models Using Bench-Scale and Intermediate-Scale Fire Experiment Data

2013

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This study presents a simplified theoretical model to predict the ignition of FRP composites of general thermal thickness (GTT) subjected to one‐sided heating. A simplified GTT heat transfer model to predict the surface temperature of GTT composite panels was developed, and the exposed surface temperature was used as ignition criterion. To validate the GTT model, intermediate scale calorimeter fire tests of E‐glass fiber reinforced polyester composite panels at three heat flux levels were performed to obtain intermediate‐scale fire testing data in a controlled condition with well‐defined thermal boundary conditions. The GTT model was also verified by using results from finite element modeling predictions. This model can be used to estimate the surface temperature increase, time‐to‐ignition, and mass loss of FRP composites for fire safety design and analysis. Copyright © 2013 John Wiley & Sons, Ltd.

Section: Resultsmentioning

confidence: 99%

“…The modified Arrhenius equation shown as Equation is used to describe the relationship between pyrolysis and temperature of composite material.

\frac{\partial ρ_{normals}}{\partial t} = - A (ρ_{normalo} - ρ_{normalch}) {((), \frac{ρ_{normals} - ρ_{normalch}}{ρ_{normalo} - ρ_{normalch}})}^{n} exp [- \frac{E}{R (T - T_{normalsh})}]

Where ρ s , ρ o , and ρ ch are the density at time t , the original density, and char density of the composite, respectively.…”

Section: Effect Of Combustion Flame On Temperature and Mass Lossmentioning

confidence: 99%

T_{normalsh} = {\begin{array}{c} center & = 0, \frac{\partial T}{\partial t} < {\dot{T}}_{Critical} \\ center & = scriptϵ {\dot{q}}^{''} normalMax ({}, \frac{\partial T}{\partial t}), \frac{\partial T}{\partial t} \geq {\dot{T}}_{Critical} \end{array}

where

{\dot{T}}_{Critical}

and

scriptϵ

are the critical temperature changing rate and a shift coefficient; they are constants for a specific material.…”

Section: Effect Of Combustion Flame On Temperature and Mass Lossmentioning

confidence: 99%

See 1 more Smart Citation

A simplified model for predicting the ignition of FRP composites with validation using intermediate‐scale fire experiment data

Tian

2013

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“…On the basis of the GTT solutions in , the surface temperature of the exposed surface of a solid subjected to

{\overset{true˙}{q}}_{e}^{″}

with the convective boundary condition at the back surface can be expressed as Eq. .…”

Section: Development Of a Heating Rate‐related Ignition Criterionmentioning

confidence: 99%

“…The MPs can be found in Table . Because of the limit available experimental data, the

T_{ig}^{\inf}

was chosen as the average ignition surface temperature (363 °C) under external heat flux 45 and 65 kW/m 2 . The critical heat flux of E‐glass/polyester composites was reported as 16 ~ 17 kW/m 2 .…”

Section: Application Of the New Ignition Criterion To Solid Materialsmentioning

confidence: 99%

An ignition criterion for combustible solids integrating surface temperature and heating rate

Tian

2014

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Summary Surface ignition temperature has been widely used as an ignition criterion for the piloted ignition of common combustible solids. However, experimental observations have shown that the surface temperature of a solid at ignition varies with external heat flux. In addition, if the external heat flux is smaller than the critical heat flux for ignition, the solid will not ignite while the actual surface temperature may be higher than the defined surface ignition temperature. To overcome these limitations and maintain the simplicity of the surface ignition temperature criterion, a new ignition criterion integrating heating rate and surface temperature is proposed, developed, and validated. Predictions based on the new criterion compare well with experimental results on piloted ignition of a thermoplastic material (black PMMA), a thermoset composite material (E‐glass fiber reinforced polyester composite) and a cellulosic material (Red Oak) subjected to different heat flux levels. Potential factors affecting the accuracy and predictive capability of the new heating rate‐related ignition temperature criterion are discussed. The method and associated procedures to construct the heating rate‐related temperature ignition criterion can be used to obtain the same ignition criterion for other combustible solids. Copyright © 2014 John Wiley & Sons, Ltd.

Effect of flame heat flux on thermal response and fire properties of char‐forming composite materials

2012

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SUMMARY This study evaluates the effect of flame heat flux on the prediction of thermal response and fire properties of a char‐forming composite material. A simplified two‐layer flame model was developed and incorporated into a heat transfer thermal model to predict the thermal response and fire reaction characteristics of a burning material. A typical char‐forming material, E‐glass reinforced polyester composite, was used in the study. A cone calorimeter was used to measure the fire reaction characteristics of the composite. The flame heat flux in a cone calorimeter test setup was estimated using the simplified flame model. Thermal response and fire property predictions with and without the effect of flame heat flux were compared with experimental data obtained from the cone calorimeter tests. Results showed that the average flame heat flux of the composite in a cone calorimeter was 19.1 ± 6 kW/m² from model predictions. The flame had a significant effect on the thermal response and fire properties of the composite around the first heat release peak but the effect decreased rapidly afterwards. Copyright © 2012 John Wiley & Sons, Ltd.