Absorption of thermal energy in PMMA by in-depth radiation

Jiang, Fenghui; Ris, John L. de; Khan, Mohammed M.

doi:10.1016/j.firesaf.2008.04.004

Cited by 80 publications

(78 citation statements)

References 16 publications

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“…Figure 8 shows results from the model with the parameter set given in Table 1 with the experimental data of Beaulieu [2], [3], Kashiwagi [1] and the coated PMMA data of Jiang et al [4]. The obvious point to note is the model confirms that in-depth absorption plays an important role in ignition at high heat flux.…”

Section: Resultsmentioning

confidence: 72%

“…This unfortunately means that there is no clearly defined optimum and any values within the dashed region will produce good fits to the experimental data. Therefore, broadly in line with other observations [4], [5] it was decided to take  / 1 as 1 mm and seek the optimum R  that minimised the residual. This process gives the best value of R  as 0.56, as Figure 6 confirms.…”

Section: Parameter Valuesmentioning

confidence: 91%

“…Measurements of the transmissivity of black PMMA (Polycast) [4] suggest that the absorption coefficient  is approximately 960m -1 , indicating a characteristic absorption depth of ~1mm. If the external heat flux is q    at the exposed surface, T is temperature and  is thermal conductivity then ignoring in-depth absorption, the characteristic thermal penetration depth assuming conduction heat transfer is q T     /   , where T  is a physically significant temperature interval.…”

Section: Introductionmentioning

confidence: 99%

“…Kashiwagi's observations of ignition of PMMA by CO 2 laser [1] show that there is significant absorption of radiation by gaseous MMA in the plume above the degrading sample and the role of gas-phase absorption in ignition and steady burning rate is unclear. Measurements of quasi-steady mass flux (the approximately steady mass loss rate per unit surface area due to out-gassing of volatiles for an initially thick sample, also referred to as "burning rate") as external heat flux is varied indicate a nonlinear trend at high heat flux [2] - [4]. This is unexpected from simple ablation theory, which predicts that steady mass flux should be proportional to the ratio of net heat flux at the exposed surface to heat of gasification [7] - [11].…”

Section: Introductionmentioning

confidence: 99%

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The effects of gas-phase and in-depth radiation absorption on ignition and steady burning rate of PMMA

Staggs

2014

Combustion and Flame

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Article:Staggs, J (2014) The effects of gas-phase and in-depth radiation absorption on ignition and steady burning rate of PMMA. Combustion and Flame, 161 (12 ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request.

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Section: Resultsmentioning

confidence: 72%

Section: Parameter Valuesmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The effects of gas-phase and in-depth radiation absorption on ignition and steady burning rate of PMMA

Staggs

2014

Combustion and Flame

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“…Hallman [8] studied the angular variation of the absorptance for clear PMMA and showed that the variation from a normal orientation to 70° is included within 15 % for wavelength lower than 2 μm. A supplementary study, with the relation given by Jiang et al [16] to calculate the reflectivity at a particular wavelength (linked to reflective index), shows that the reflected ratio varies between 0.038 and 1 when the angle formed with the normal of the sample is between 0 and 90° (0.17 for an angle of 70° and 0.39 for an angle of 80°).…”

Section: Discussionmentioning

confidence: 98%

Comparison of Pyrolysis Behavior Results between the Cone Calorimeter and the Fire Propagation Apparatus Heat Sources

Girods¹,

Bal²,

Biteau³

et al. 2011

Fire Safety Science - Proceedings of the 10th International Sym

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The cone calorimeter and the fire propagation apparatus (FPA) are often used to carry out flammability studies of materials. There are various differences in the set-up of these two devices that could lead to different fire behaviour for the same material. Among these, the impact of the different heat sources used is studied here. The cone calorimeter employs an electrical cone heater and the FPA uses tungsten lamps to radiate a given heat flux level to the sample. Experiments are conducted in the FPA set-up using a conical heater or tungsten lamps as the heat source with clear PMMA and wood samples. Mass loss and temperature measurements are taken during the tests, and the bubble layer depth is measured after the tests. Significant differences in pyrolysis behaviour of both samples between the cone calorimeter and the FPA are consistently observed at the same heat flux level. These different pyrolysis behaviours can be explained by the wavelength dependency of the radiative material properties (reflectance, absorptance and transmittance). This conclusion is in agreement with, and provides an experimental confirmation, to theoretical findings in previous studies.

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Numerical simulations of polymer pyrolysis rate: Effect of property variations

Linteris

2010

Fire and Materials

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SUMMARYThe mass loss rate (MLR) of poly(methyl methacrylate) (PMMA) exposed to known radiant fluxes is simulated with two recently developed numerical codes, the National Institute of Standards and Technology (NIST) Fire Dynamics Simulator (FDS) and the Federal Aviation Administration (FAA) ThermaKin. The influence of various material properties (thickness, thermal conductivity, specific heat, absorption of infrared radiation, heat of reaction) on mass loss history is assessed, via their effect on the ignition time, average MLR, peak MLR, and time to peak. The two codes predict the influence of material parameters on the MLR in the order of decreasing importance: heat of reaction, thickness, specific heat, absorption coefficient, thermal conductivity, and activation energy of the polymer decomposition. Changes in the material properties also influence the MLR curves by switching the sample from thermally thick to thermally thin. The two numerical codes are generally in very good agreement for their predictions of the MLR vs time curves, except when in-depth absorption of radiation was important.

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Absorption of thermal energy in PMMA by in-depth radiation

Cited by 80 publications

References 16 publications

The effects of gas-phase and in-depth radiation absorption on ignition and steady burning rate of PMMA

The effects of gas-phase and in-depth radiation absorption on ignition and steady burning rate of PMMA

Comparison of Pyrolysis Behavior Results between the Cone Calorimeter and the Fire Propagation Apparatus Heat Sources

Numerical simulations of polymer pyrolysis rate: Effect of property variations

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