Thermal particle image velocity estimation of fire plume flow

Zhou, Xiangyang; Sun, Lulu; Mahalingam, Shankar; Weise, David R.

doi:10.1080/00102200302376

Cited by 19 publications

(16 citation statements)

References 22 publications

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“…They theorized that as these vertically oriented vortices tilt together, their combined motion causes the vortices to tip forward at a sharp angle, forming a hairpin-shaped vortex that causes a turbulent burst. This technique has also been applied in a laboratory setting to study motions within fire plumes (Zhou et al 2003).…”

Section: J O U R N a L O F A P P L I E D M E T E O R O Lmentioning

confidence: 99%

Infrared Imagery of Crown-Fire Dynamics during FROSTFIRE

Coen¹,

Mahalingam²,

Daily³

2004

J. Appl. Meteor.

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A thorough understanding of crown-fire dynamics requires a clear picture of the three-dimensional winds in and near the fire, including the flaming combustion zone and the convective updrafts produced by the fire. These observations and analyses present a unique high-spatial-resolution and high-temporal-resolution perspective of the motions within crown fires propagating up a forested 20Њ slope under light winds of 3 m s Ϫ1 during the FROSTFIRE experiment in interior Alaska. The purpose of this work is to calculate combustion-zone winds and examine mechanisms for the rapid propagation of crown fires. An infrared imager was used to detect hightemperature regions produced by incandescent soot particles in and near the fire and to produce a sequence of high-frequency (60 Hz), high-resolution (0.375 m ϫ 0.8 m) two-dimensional images of temperature. An imageflow-analysis technique was applied to these data to derive wind fields in the image plane. Maximum updrafts of 32-60 m s Ϫ1 accompany maximum downdrafts of 18-30 m s Ϫ1 . Horizontal wind speeds of 12-28 m s Ϫ1 show strong inflow into the base of the convective updrafts and imply recirculation of air and incomplete combustion products from the fire. Motions were more complex than a single large convective plume or many buoyant treescale plumes rising separately. Instead, repeated examples of narrow flaming fingers, representing a scale larger than individual trees, initially burst upslope along the ground for tens of meters at speeds up to 28-48 m s Ϫ1 before turning upward. These bursts exceeded ambient environmental winds, those considered to be driving the fire, by a factor of 10 and were low enough to propagate the crown fire actively by both igniting and preheating/ drying canopy fuel ahead of the fire. Average spread rates were 0.75-1.11 m s Ϫ1 , with a peak 10-s spread rate of 1.26 m s Ϫ1 . This powerful, dynamic mechanism of fire spread could explain firefighter reports of being overtaken by ''fireballs.''

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Section: J O U R N a L O F A P P L I E D M E T E O R O Lmentioning

confidence: 99%

Infrared Imagery of Crown-Fire Dynamics during FROSTFIRE

Coen¹,

Mahalingam²,

Daily³

2004

J. Appl. Meteor.

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“…This is because in practice, a fire-induced convection plume in the open is featured as the air entrainment at the edges of the plume enclosure and subsequent arbitrary formation of low-frequency eddies at the edges of the plume and even within the plume, as closely observed by Zhou et al (2003). Equation (11) indicates a proportionality of gas flow velocity to E 1=3 c .…”

Section: Interpretation Of the Equation For Determining Gas Velocity mentioning

confidence: 85%

Analytical Model for Determining Thermal Radiance of Fire Plumes with Implication to Wildland Fire

Wang

2009

Combustion Science and Technology

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The present work aims at developing an analytical model for evaluating the thermal radiation of a fire plume formed by burning wildland fuels at a given burning intensity and crosswind. By resolving the equations governing gas continuity, momentum, and energy conservation for a convective (buoyancy) plume, gas velocity and temperature profile along the central line of the plume were determined, which enables a quantification of radiation intensity of flame and buoyancy plume zones. Model features are examined, and the predicted results are compared with the available experimental data. It is found that for a fire with burning intensity exceeding 600 kW m 2 1 , the radiant heat emittable from its plume is not only contributed by the luminous flame zone but also by the buoyancy plume significantly. This indicates, for the first time, a necessity of inclusion of the contribution of the buoyancy plume in evaluating thermal impact of a fire plume on a receiver in the environment. The current work provides an important basis for convenient but reliable assessment of the fire risk of buildings raised by the occurrence of a wildland fire in adjacent areas.

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“…Usually, models of smoke plumes and jets are based on Reynolds-averaged Navier-Stokes equations (RANS) [16][17][18][19][20][21][22][23][24], large eddy simulation (LES) [18,[24][25][26][27][28], and direct numerical simulations [29]. Frequently the LES technique provides a better description of turbulence-related effects, but requires finer grids and longer computation time than RANS-based models.…”

Section: Formulation Of the Smoke-plume Modelmentioning

confidence: 99%