Radiation blockage in small scale PMMA combustion

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

doi:10.1016/j.proci.2010.08.007

Cited by 30 publications

(7 citation statements)

References 18 publications

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“…Mass loss rates were measured when samples were pyrolyzed in a pure nitrogen atmosphere and also burnt in air with 18%, 30% and 40% ambient oxygen-nitrogen, respectively, while being subjected to various external radiant fluxes. Some of the experimental results were already reported in the previous paper [31].…”

Section: Definition and Measurement Of Flame Heat Transfer Blockagementioning

confidence: 66%

“…Accurate evaluation on gas absorption and emission is the key as well as the difficult point in this model development, especially for fuel vapors. As the prophase work of this theoretical model, previous paper [31] provides details of the study and prediction of the absorptivity and emissivity of gas-soot mixtures. For properly handling wavelength dependence of the fuel vapor, an approximate band model was developed and inserted into the RADCAL program, which is based on the statistical narrow band model, to compute radiances from mixtures of the gases.…”

Section: Absorptivity and Emissivity Of Flamesmentioning

confidence: 99%

“…(1) Outward radiant heat flux For a volume of gas-soot mixture with given temperature profile T (x) and optical thickness profile ξ(x), the outward radiance can be described by the following universal equation and boundary conditions [33]: [31]. Solving this differential equation with the boundary condition, the outward radiance is derived as…”

Section: Radiances and Radiant Heat Fluxesmentioning

confidence: 99%

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Heat transfer blockage in small scale combustion of polymers

Jiang

Ris

et al. 2011

Sci. China Technol. Sci.

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Flame heat transfer blockage occurs as fuel vapors, soot and products of combustion near a burning fuel surface block much of the heat feedbacks (including external radiative heat flux) to the fuel surface of a burning object. Blockage clearly affects burning rates and heat release rates of fires. This needs to be included when calculating flame heat transfer in fire growth models. An understanding of burning of materials in small scale fires is of broad and vital importance for predicting their burning performance in large scale fires. The blockage phenomenon was clearly observed and quantitatively measured in experiments that took advantage of the unique capability of the Fire Propagation Apparatus (FPA) of being able to vary the ambient oxygen concentrations. An indirect measurement approach was established which provides an experimental understanding of the concept of the blockage. The measurements were further explained by a one-dimensional steady-state model of a diffusion flame, which focuses on the radiant absorption and emission by the gas-soot mixture of flames. The theoretical model provides a greater understanding of the fundamental knowledge of the blockage. The overall heat transfer blockage factor can be up to 0.3 -0.4 for PMMA and POM. The factor and its components are nearly independent of the external radiation, but increase as the ambient oxygen concentration rises. A comparison between experimental data and model prediction shows a good agreement. polymer, flame heat transfer blockage, gas-soot mixture, gas absorption and emission, external radiant heat flux, oxygen concentration Citation: Jiang F H, Qi H Y, de Ris J L, et al. Heat transfer blockage in small scale combustion of polymers.

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Section: Definition and Measurement Of Flame Heat Transfer Blockagementioning

confidence: 66%

Section: Absorptivity and Emissivity Of Flamesmentioning

confidence: 99%

Section: Radiances and Radiant Heat Fluxesmentioning

confidence: 99%

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Heat transfer blockage in small scale combustion of polymers

Jiang

Ris

et al. 2011

Sci. China Technol. Sci.

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“…这便是能量守恒方程(14)中的辐射源项. 它包含温度分布与光学厚度分布, 而后者却也由温度分布和组分分布决定 [31] . 于是, 利用能量守恒方程, 便可最终对一维温度分布进行数值解, 从而使整个问题得以求解.…”

Section: 辐射传递方程和辐射热流密度方程unclassified

聚合物小尺寸燃烧中的传热阻碍

KHAN¹,

祁²,

de³

et al. 2011

Sci. Sin.-Tech.

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“…Engineering approaches to the analysis and characterization of the pyrolysis and combustion of materials are discussed in Refs. [7,8].…”

Section: Introductionmentioning

confidence: 99%

Time‐resolved measurements of pyrolysis and combustion products of PMMA

et al. 2012

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We studied transient chemical speciation during high‐temperature solid material pyrolysis and combustion in air. Our objective was to develop a database of chemical burn signatures. The material tested was the thermoplastic PMMA. Material samples were heated in an infrared furnace until they pyrolyzed, ignited, and combusted in air. Time‐resolved quantitative measurements of the exhaust species CO2, O2, hydrocarbons, and CO along with exhaust gas temperature were obtained. Two categories of experiments were conducted: (1) pyrolysis tests in which there was no combustion; (2) combustion tests with chemical reaction and heat release. During heating, the sample underwent numerous processes that appear as diagnostic sequences. In the pyrolysis tests, as the furnace temperature was raised, the CO and hydrocarbon (HC) signals underwent transition from one peak to two peaks. In the combustion tests, spontaneous ignition occurred at higher test temperatures as evidenced by an exothermic reaction reported by the thermocouples, leading to three‐peak CO and HC profiles. The measured O2/CO2 ratio of 1.3 ± 0.1 agreed with stoichiometric methyl‐methacrylate monomer decomposition. Calculations of the power output using two independent methods supported (1) that combustion was experimentally observed in the furnace, and (2) the accuracy of the combustion gas analysis. Copyright © 2012 John Wiley & Sons, Ltd.

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Radiation blockage in small scale PMMA combustion

Cited by 30 publications

References 18 publications

Heat transfer blockage in small scale combustion of polymers

Heat transfer blockage in small scale combustion of polymers

聚合物小尺寸燃烧中的传热阻碍

Time‐resolved measurements of pyrolysis and combustion products of PMMA

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