Effects of external radiant flux and ambient oxygen concentration on nonflaming gasification rates and evolved products of white pine

Kashiwagi, Takashi; Ohlemiller, Thomas J.; Werner, K.G.

doi:10.1016/0010-2180(87)90125-8

Cited by 62 publications

(70 citation statements)

References 6 publications

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“…As with the thermoplastic model above, when using Equations 2.11 -2.18 there is no way to account for the influence of oxygen on the pyrolysis reaction, unless Z, E, and ∆H p are made explicit functions of the ambient oxygen concentration or an additional oxidative reaction is added. To illustrate the importance of oxygen concentration on the decomposition of charring materials, the mass loss rate and surface temperature of white pine irradiated at 40 kW/m 2 at three different oxygen concentrations [84] is shown in Figure 2.5. It can be seen from Figure 2.5a that the mass loss rate in air is approximately double that in nitrogen.…”

Section: Comprehensive Pyrolysis Models: Charring Materialsmentioning

confidence: 99%

“…Ohlemiller, Kashiwagi, and Werner [84,207] experimentally studied the effects of ambient oxygen concentration on the nonflaming gasification of irradiated white pine.…”

Section: Charring Gasification -White Pinementioning

confidence: 99%

“…Reference [84] The experiments of Kashiwagi, Ohlemiller, and Werner [84] have been simulated by Jia et al [60] and Weng et al [208] using integral charring models. Jia et al [60] modeled only the experiments [84] that were conducted in pure nitrogen because their model did not include exothermic char oxidation.…”

Section: Charring Gasification -White Pinementioning

confidence: 99%

“…Jia et al [60] modeled only the experiments [84] that were conducted in pure nitrogen because their model did not include exothermic char oxidation. Weng et al [208] recently modeled the experiments [84] with a previously-developed integral model that was modified to explicitly consider char oxidation. Both groups obtained reasonably good agreement between their model calculations and the experimental data.…”

Section: Charring Gasification -White Pinementioning

confidence: 99%

“…Shen et al [211] obtained good agreement between measured and calculated temperatures (at the surface and in depth), but did not present a comparison of modeled and measured mass loss rates. Weng et al [208] recently modeled the same set of experiments [84] that are modeled here. They included the effect of char oxidation through the surface boundary condition.…”

Section: Oxidative Pyrolysismentioning

confidence: 99%

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Generalized pyrolysis model for combustible solids

Lautenberger

Fernandez-Pello

2009

Fire Safety Journal

307

259

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This dissertation presents the derivation, numerical implementation, and verification/validation of a generalized model that can be used to simulate the pyrolysis, gasification, and burning of a wide range of solid fuels encountered in fires. The model can be applied to noncharring and charring solids, composites, intumescent coatings, and smolder in porous media. Care is taken to make the model as general as possible, allowing the user to determine the appropriate level of complexity to include in a simulation. The model considers a user-specified number of gas phase and condensed phase species, each having its own temperature-dependent thermophysical properties.Any number of heterogeneous (gas-solid) or homogeneous (solid-solid or gas-gas) reactions can be specified. Both in-depth radiation transfer through semi-transparent media and radiation transport across pores are considered. Volume change (surface regression or swelling/intumescence) is handled by allowing the size of grid points to change as dictated by mass conservation. All volatiles generated inside the solid escape to the ambient with no resistance to mass transfer unless a pressure solver is invoked; the resultant flow of volatiles is then calculated according to Darcy's law. A gas phase 2 convective-diffusive solver can be invoked to determine the composition of the volatiles.Oxidative pyrolysis is simulated by modeling diffusion of oxygen from the ambient into the pyrolyzing solid where it may participate in reactions. Consequently, the mass flux and composition of volatiles escaping from the solid can be calculated. To aid in determining the required input parameters, the model is coupled to a genetic algorithm that can be used to estimate the required input parameters from bench-scale fire tests or thermogravimetric analysis.

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Section: Comprehensive Pyrolysis Models: Charring Materialsmentioning

confidence: 99%

“…Ohlemiller, Kashiwagi, and Werner [84,207] experimentally studied the effects of ambient oxygen concentration on the nonflaming gasification of irradiated white pine.…”

Section: Charring Gasification -White Pinementioning

confidence: 99%