Pyrolysis and ignition of a polymer by transient irradiation

Vermesi, Izabella; Roenner, Nils; Pironi, Paolo; Hadden, Rory M.; Rein, Guillermo

doi:10.1016/j.combustflame.2015.08.006

Cited by 74 publications

(37 citation statements)

References 14 publications

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“…At higher loadings the changes to the thermal properties are starting to become significant [29,30] but have to the best of our knowledge not yet been investigated for their effect on flammability. This has been related in the past for other systems to improvements in flammability [31,32] .…”

Section: Introductionmentioning

confidence: 99%

Simultaneous improvements in flammability and mechanical toughening of epoxy resins through nano-silica addition

Roenner

Hutheesing

Fergusson³

et al. 2017

Fire Safety Journal

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Section: Introductionmentioning

confidence: 99%

Simultaneous improvements in flammability and mechanical toughening of epoxy resins through nano-silica addition

Roenner

Hutheesing

Fergusson³

et al. 2017

Fire Safety Journal

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“…Heat, momentum, and mass transfer as well as the chemical processes must be considered [12]. These simulations have been performed for a variety of materials, from woods and other natural materials [12], to polymers such as PMMA [13], and polyurethanes [14]. An example of a numerical code used to simulate the pyrolysis of these types of materials is Gpyro [15].…”

Section: Literature Reviewmentioning

confidence: 99%

Modeling Heat Transfer and Pressurization of Polymeric Methylene Diisocyanate (PMDI) Polyurethane Foam in a Sealed Container

Scott¹

2018

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Polymer foam encapsulants provide mechanical, electrical, and thermal isolation in engineered systems. It can be advantageous to surround objects of interest, such as electronics, with foams in a hermetically sealed container to protect the electronics from hostile environments, such as a crash that produces a fire. However, in fire environments, gas pressure from thermal decomposition of foams can cause mechanical failure of the sealed system. In this work, a detailed study of thermally decomposing polymeric methylene diisocyanate (PMDI)-polyether-polyol based polyurethane foam in a sealed container is presented. Both experimental and computational work is discussed. Validation experiments, called Foam in a Can (FIC) are presented. In these experiments, 320 kg/m 3 PMDI foam in a 0.2 L sealed steel container is heated to 1073 K at a rate of 150 K/min and 50 K/min. FIC is tested in two orientations, upright and inverted. The experiment ends when the can breaches due to the buildup of pressure from the decomposing foam. The temperature at key locations is monitored as well as the internal pressure of the can. When the foams decompose, organic products are produced. These products can be in the gas, liquid, or solid phase. These experiments show that the results are orientation dependent: the inverted cans pressurize, and thus breach faster than the upright. There are many reasons for this, among them: buoyancy driven flows, the movement of liquid products to the heated surface, and erosive channeling that enhance the foam decomposition. The effort to model this problem begins with Erickson's No Flow model formulation. In this model, Arrhenius type reactions, derived from Thermogravimetric Analysis (TGA), control the reaction. A three-step reaction is used to decompose the PMDI RPU (rigid polyurethane foam) into CO2, organic gases, and char. Each of these materials has unique properties. The energy equation is used to solve for temperature through the domain. Though gas is created in the reaction mechanism, it does not advect, rather, its properties are taken into account when calculating the material properties, such as the effective conductivity. The pressure is calculated using the ideal gas law. A rigorous uncertainty quantification (UQ) assessment, using the mean value method, along with an analysis of sensitivities, is presented for this model. The model is also compared to experiments. In general, the model works well for predicting temperature, however, due to the lack of gas advection and presence of a liquid phase, the model does not predict pressure well. 2 Porous Media Model is then added to allow for the advection of gases through the foam region, using Darcy's law to calculate the velocity. Continuity, species, and enthalpy equations are solved for the condensed and gas phases. The same reaction mechanism as in the No Flow model is used, as well as material properties. A mesh resolution study, as well as a calibration of parameters is conducted, and the model is compared to experimental results. This m...

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“…Ignition, spontaneous or piloted, occurs only when some sorts of ignition criteria are satisfied. Four criteria can be found in the literature and were summarized by Vermesi [ 15 ], namely critical temperature, critical mass flux, critical energy and time-energy squared. The critical temperature is reliable for a thermally thick solid exposed to a constant irradiation (e.g., Ref.…”

Section: Introductionmentioning

confidence: 99%

Effects of Combined Surface and In‐Depth Absorption on Ignition of PMMA

Gong

Chen

et al. 2016

Materials

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A one-dimensional numerical model and theoretical analysis involving both surface and in-depth radiative heat flux absorption are utilized to investigate the influence of their combination on ignition of PMMA (Polymethyl Methacrylate). Ignition time, transient temperature in a solid and optimized combination of these two absorption modes of black and clear PMMA are examined to understand the ignition mechanism. Based on the comparison, it is found that the selection of constant or variable thermal parameters of PMMA barely affects the ignition time of simulation results. The linearity between tig−0.5 and heat flux does not exist anymore for high heat flux. Both analytical and numerical models underestimate the surface temperature and overestimate the temperature in a solid beneath the heat penetration layer for pure in-depth absorption. Unlike surface absorption circumstances, the peak value of temperature is in the vicinity of the surface but not on the surface for in-depth absorption. The numerical model predicts the ignition time better than the analytical model due to the more reasonable ignition criterion selected. The surface temperature increases with increasing incident heat flux. Furthermore, it also increases with the fraction of surface absorption and the radiative extinction coefficient for fixed heat flux. Finally, the combination is optimized by ignition time, temperature distribution in a solid and mass loss rate.

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Pyrolysis and ignition of a polymer by transient irradiation

Cited by 74 publications

References 14 publications

Simultaneous improvements in flammability and mechanical toughening of epoxy resins through nano-silica addition

Simultaneous improvements in flammability and mechanical toughening of epoxy resins through nano-silica addition

Modeling Heat Transfer and Pressurization of Polymeric Methylene Diisocyanate (PMDI) Polyurethane Foam in a Sealed Container

Effects of Combined Surface and In‐Depth Absorption on Ignition of PMMA

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