A theoretical explanation of the influence of char formation on the ignition of polymers

Watt, Simon; Staggs, J.E.J.; McIntosh, Andy C.; Brindley, J.

doi:10.1016/s0379-7112(01)00008-x

Cited by 19 publications

(22 citation statements)

References 11 publications

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“…When the ablative sample is exposed to high temperature and high velocity fluid stream, decomposition of resin begins at pyrolysis temperature, and subsequently char layer ablation occurs at higher temperature [15][16][17][18]. The free surface of the sample under the influence of high temperature stream is continuously spilled.…”

Section: Mathematical Model Of Ablationmentioning

confidence: 99%

“…Therefore, three zones are formed ( Fig. 1): the virgin material, the pyrolysis zone and the porous char layer [11,15,18]. The char layer in nanocomposite samples is a dense ceramic layer [11].…”

Section: Mathematical Model Of Ablationmentioning

confidence: 99%

“…The main assumptions on which the model rests are listed below [17][18][19][20][21][22][23] frequency factor (s −1 ) A c frequency factor for char formation (s −1 ) A g frequency factor for gas formation (s −1 ) c heat capacity (J kg −1 K −1 ) c g heat capacity of the gas (J kg −1 K −1 ) E activation energy of thermal degradation (J mol −1 ) E c activation energy for char formation (J mol −1 ) E g activation energy for gas formation (J mol −1 ) G mass rate of gaseous products of thermo-…”

Section: Mathematical Model Of Ablationmentioning

confidence: 99%

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Ablation mechanism of polymer layered silicate nanocomposite heat shield

Bahramian

Kokabi

2009

Journal of Hazardous Materials

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Section: Mathematical Model Of Ablationmentioning

confidence: 99%

Section: Mathematical Model Of Ablationmentioning

confidence: 99%

Section: Mathematical Model Of Ablationmentioning

confidence: 99%

See 1 more Smart Citation

Ablation mechanism of polymer layered silicate nanocomposite heat shield

Bahramian

Kokabi

2009

Journal of Hazardous Materials

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“…Ignition is determined using the critical mass flux (CMF) criterion in the following way (see [6,7] for details). The model equations are integrated forward in time and the total mass flux of volatiles, i.e.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…In this work, the cone calorimeter is again used as the fire test instrument and the results are interpreted using an extended version of a pyrolysis model developed by Staggs in previous papers [5,6].…”

Section: Introductionmentioning

confidence: 99%

The Effect Of Paint On The Ignition Resistance Of Plywood And Chipboard

Staggs¹,

Phylaktou²,

Mccreadie³

2003

Fire Safety Science - Proceedings of the Seventh International

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In this work the influence of paint loading on the time to ignition is investigated for chipboard and plywood. Unpainted and painted specimens, 100-mm-square, 18-mmthick, were subjected to constant incident heat fluxes of 35, 50 and 65 kWm -2 in a cone calorimeter. The time to ignition, mass loss rate and heat release rate are reported as functions of time and of the initial dried mass of paint on the sample (as opposed to number of coats reported in previous work by others). It was found that addition of a small amount of paint (up to 2 g or 200 g/m 2 -equivalent to 2 coats) increased the ignition time by a maximum factor of approximately two. However, addition of even more paint (up to about 4.5 g or 450 g/m 2 -equivalent to 5 coats) actually reduced the ignition time by up to a factor of approximately 7 relative to the unpainted material. A critical paint loading appears to exist (which decreases with increasing external heat flux), at which the physical mechanism controlling the ignition process changes. A mathematical model with simple kinetics was used in order to interpret the results and understand the ignition behaviour.

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Extension and evaluation of the integral model for transient pyrolysis of charring materials

et al. 2005

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SUMMARYIn most numerical simulations of fire growth and fire spread, pyrolysis models are required to calculate the reaction of the solid material to an incident heat flux. Important results of the pyrolysis model are the mass release rate of combustible pyrolysis gases and the surface temperature. In this paper an integral model is evaluated for the prediction of pyrolysis of charring materials. An existing integral model is extended with a finite and semi-infinite cooling state. In this state both char and virgin material are present but the pyrolysis reactions have been interrupted due to insufficient heat supply. The results show that such a cooling state can occur in flame spread calculations. Simulations with the integral model are further compared with the results of a moving grid model, which has the same physical basis. Unlike the integral model, the moving grid model does not require any assumption for the temperature profile in the solid. The influence of the quadratic assumed temperature profile in the integral model on the accuracy of the predictions of the mass release rate of pyrolysis gases is evaluated for several cases. It is shown that the integral model has problems with sudden variations of the external heat flux.

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A theoretical explanation of the influence of char formation on the ignition of polymers

Cited by 19 publications

References 11 publications

Ablation mechanism of polymer layered silicate nanocomposite heat shield

Ablation mechanism of polymer layered silicate nanocomposite heat shield

The Effect Of Paint On The Ignition Resistance Of Plywood And Chipboard

Extension and evaluation of the integral model for transient pyrolysis of charring materials

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