Chemical flame heights

Newman, Jeffrey S.; Wieczorek, Christopher J.

doi:10.1016/j.firesaf.2004.02.003

Cited by 21 publications

(10 citation statements)

References 4 publications

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“…Newman and Wieczorek, [15] showed that this definition of chemical flame height is in reasonable agreement with Heskestad's correlation, (1) applied to Orloff et al's., [16] data.…”

Section: Introductionsupporting

confidence: 57%

A computational flame length methodology for propane jet fires

Cumber

Spearpoint

2006

Fire Safety Journal

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This paper presents a flame length methodology that mimics the human eye or camera using a CFD framework to calculate the flame structure. A parabolic flow model which accounts for turbulent combustion, soot kinetics and visible radiation distribution is extended to predict both rim-stabilised and lifted jet fires. The model is calibrated using a selected set of jet fire experiments and then validated against a wider range of data. Good agreement over a range of scales is demonstrated particularly when taking the degree of repeatability of the experiments into account. The flame length prediction is found to be insensitive to receiver location so long as the receiver is one or more flame lengths from the fire.

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“…Newman and Wieczorek, [15] showed that this definition of chemical flame height is in reasonable agreement with Heskestad's correlation, (1) applied to Orloff et al's., [16] data.…”

Section: Introductionsupporting

confidence: 57%

A computational flame length methodology for propane jet fires

Cumber

Spearpoint

2006

Fire Safety Journal

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“…Previous research has been conducted using a similar technique of imaging the flame at its smoke point in order to measure the flame's luminous height (Lin and Faeth, 1996), while other experiments have measured the flame's height as its stoichiometric contour. Newman and Wieczorek (2004) measured both the luminous and the stoichiometric smoke point heights in diffusion flames and showed very little difference between the two heights. Since the luminous flame height has proven useful in comparison to the soot volume fraction measurements (Lin and Faeth, 1996), the current investigation focuses on the flame's luminous smoke point height.…”

Section: Smoke Pointmentioning

confidence: 99%

Effect of Dilution, Pressure, and Velocity on Smoke Point in Laminar Jet Flames

Yelverton

Roberts

2008

Combustion Science and Technology

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Smoke point measurements of diluted methane and ethylene flames were made in a co-flowing laminar jet diffusion flame at pressures up to 8 atm. The smoke point corresponds to the fuel flow rate where the soot production is exactly offset by the soot oxidation, and as such is sensitive to changes in rates of production or oxidation. Flame height in these flames was measured as a function of pressure, diluent, and dilution level as well as both fuel exit velocity profile (i.e., plug or parabolic) and fuel=air velocity ratio. As pressure increases, the smoke point became less sensitive to diluent or dilution level. In addition to heat capacity and thermal diffusivity differences between CO 2 and He for example, the large differences in kinematic viscosity was shown to play an important role in the diluent's ability to suppress the fuel's propensity to form soot.

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“…For the constant N Hesk : c p is the specific heat of air, T 1 is the ambient temperature, DH c is the fuel's heat of combustion, Z st is a stoichiometric coefficient, and _ Q is the heat release rate. This correlation was originally created by Heskestad to predict the luminous height of a turbulent diffusion flame but was reconfirmed by Newman and Wieczorek [33] to give accurate predictions of the chemical flame height in surface fires. It is the chemical flame height which is important to soot formation and particulate emission.…”

Section: Flame Characteristicsmentioning

confidence: 87%

Zonal-Based Emission Source Term Model for Predicting Particulate Emission Factors in Wildfire Simulations

et al. 2020

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A physics/chemistry-based numerical model for predicting the emission of fine particles from wildfires is proposed. This model implements the fundamental mechanisms of soot formation in a combustion environment: soot nucleation, surface growth, agglomeration, oxidation, and particle fragmentation. These mechanisms occur on a scale too fine for the discretization of most wildfire models, which need to simulate landscape-scale dynamics. As a result this model implements a zonal approach, where the computed soot particle distribution is partitioned into process zones within a single resolved grid cell. These process zones include: an inception zone (for nucleation), a heating zone (for coagulation, surface growth, and fragmentation), a reaction zone (for oxidation), and a quenched zone (for atmospheric processes). Governing mechanisms are applied to the appropriate zones to predict total particle growth and emission. The proposed model is implemented into HIGRAD/ FIRETEC, a physics-based wildfire simulation code which couples interactions between fire, fuels, atmosphere, and topography on a landscape scale. Fire simulations among grasslands and conifer forests are performed and compared against experimental data for emission factors.

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Chemical flame heights

Cited by 21 publications

References 4 publications

A computational flame length methodology for propane jet fires

A computational flame length methodology for propane jet fires

Effect of Dilution, Pressure, and Velocity on Smoke Point in Laminar Jet Flames

Zonal-Based Emission Source Term Model for Predicting Particulate Emission Factors in Wildfire Simulations

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