Reconstruction of fire whirls using scale models

Soma, Seiji; Saito, Kozo

doi:10.1016/0010-2180(91)90107-m

Cited by 128 publications

(86 citation statements)

References 9 publications

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“…Under extreme condition, a fire whirl was responsible for 38,000 deaths caused by The Great Kanto Earthquake that struck the downtown Tokyo area in 1923 [6]. Soma and Saito [6] collected a historical record of large scale fire whirls and categorized them into three different types. Pitts [3] provided a comprehensive review on wind-aided fires and included fire whirls in his review.…”

Section: Introductionmentioning

confidence: 99%

“…This approach requires some guess work because there are no reliable velocity measurement data that can specify structures of the fire whirl. Difficulty of the measurement lies in that the fire whirls associated with large scale mass fires appear without warning and when they occur, they may only last for seconds to no more than a few minutes [6,7]. Access to those fire whirls for measurement would be both highly fortuitous and highly dangerous.…”

Section: Introductionmentioning

confidence: 99%

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Flow Structure Of A Fixed-frame Type Firewhirl

Hassan¹,

Kuwana²,

Saito³

et al. 2005

Fire Safety Science - Proceedings of the Eigth International Sy

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This paper reports the results of both experimental and numerical investigations on a laboratory-scale fixed-frame type fire whirl. We designed a fixed-frame type fire whirl generator consisting of two vertically oriented split PMMA cylinders which are placed in an off-center location to create a small compartment with a slit at each end. At the center of the compartment floor, a 5 cm-diameter 1-propanol pool fire generated upward buoyancy flow and fresh air entering the compartment through the slits, generating swirl motion in the compartment. This is a fixed-frame type fire whirl. We measured transient 2-D radial, tangential, and axial velocity profiles with 2-D particle image velocimetry (PIV). The radial and tangential velocity profiles were measured at four different heights (5, 10, 15, and 20 cm) along the axis of the fire whirl, while the axial velocity profiles were measured at 10 cm in the axial height. We also measured relative temperature distributions of the fire whirl with an infrared thermograph technique. These measurements show that both the tangential velocity and the absolute value of radial velocity increase with an increase in the radial distance, while they remain relatively constant along the axis. Our IR data also show that the relative temperature map stays unchanged along the axis. The radial locations where the maximum radial and tangential velocity were measured approximately coincide and are at about 3.5 cm on the radial coordinate, while the visible spinning flame location is at about 1.2 cm. This shows a difference in the velocity structure between open pool fires and fire whirls, because the location of the maximum flow velocity and visible flame approximately coincides for laminar open pool fires. A simple laminar 2-D axisymmetric CFD model was developed to simulate these measured flow and temperature structures created by the fire whirl, and reasonable agreement was obtained.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Flow Structure Of A Fixed-frame Type Firewhirl

Hassan¹,

Kuwana²,

Saito³

et al. 2005

Fire Safety Science - Proceedings of the Eigth International Sy

Self Cite

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“…Some success has been reported in the literature in this regard. For instance, swirling fires can be generated by surrounding the fire with a rotating mesh cylinder [I], or by small multiple fires placed in a wind tunnel [2], or in free air with a prevailing wind [3]. Another recent scheme of creating swirling fires is by means of channeling the entrainment flows induced by the fire itself in a tangential direction around the f i e , thus imparting rotational motion to the fire causing it to swirl.…”

Section: Introductionmentioning

confidence: 99%

Simulations Of Swirling Fires Controlled By Channeled Self-generated Entrainment Flows

Satoh¹,

Yang²

1997

Fire Safety Science - Proceedings of the 5th International Symp

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In an earlier study experimental observations of swirling fires based on self-generated swirling flows were undertaken. The swirl was caused by properly channeling the entrainment flow due to the fire itself. It was found that one of the most significant parameters governing the combustion process and the stability of the whirling flame was the entrainment flow controlled by the presence of symmetrical gaps separating the square vertical bounding walls surrounding the fire. In the present study, the physical phenomena of how the channeled entrainment flow affects the whirling flame has been simulated numerically by an approximate fire field model, which captures essentially the same whirling fire phenomena as observed in the experiments. In particular, the quantitative effect of gap sizes between bounding walls and several other parameters such as heat load, fuel size, and enclosure wall height on the plume dynamics and whirling flame stability have been numerically determined.

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“…Fire whirls, generally caused by an unexpected vortex flow effect on the flame burning, are often reported in forest and urban fires with devastating damage to life and property, and also contribute to spot fires by picking up large firebrands and scattering them over a wide area [1][2][3]. During the past half century, a number of theoretical and experimental studies have been conducted to provide a basic understanding of the fire whirl phenomenon.…”

Section: Introductionmentioning

confidence: 99%

“…Morton [5] especially examined the origin, generation and amplification of concentrated vorticity of fire whirl by analysis of relevant vorticity equations. The burning behaviors including burning rate, flame height and flame temperature were mainly investigated by experimental researchers, such as Emmons and Ying [7] by rotating screen-flame model, Soma and Saito [2] and Kuwana et al [3] utilizing bench-scale model by scaling laws, and Lei et al [8] by fixed frame-flame model. In recent years, numerical simulations [9,10] have also been widely used for solving the Navier-Stokes or vorticity equations of fire whirl, in order to interpret the detailed fluid flow structure.…”

Section: Introductionmentioning

confidence: 99%

Experimental Research on Burning Rate, Vertical Velocity and Radiation of Medium-Scale Fire Whirls

Zhou¹,

Liu²,

Satoh³

2011

Fire Safety Science - Proceedings of the 10th International Sym

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Fire whirls are often reported in forest and urban fires with devastating damage to life and property. This work conducted experiments using a medium-scale facility to study the initiation mechanism, the vertical velocity and radiative heat transfer of fire whirls. Heptane was used as the fuel in the experiments. The variations of burning rates versus time indicate that the drag force on the root of the flame plays an important role in the initiation and decay of a fire whirl. Analyses show that the pressure difference due to whirling, characterized by the circulation  , significantly affects the vertical centerline velocity. The variation of the vertical centerline velocity is correlated by , where m is nearly 1.1 for both fire whirls and general pool fires. It is also found that the radiative fraction of fire whirls is nearly 42 %, 1.4 times as large as that for general pool fires. The radiative heat feedback fraction is shown to increase with pool diameter, similarly as for general pool fires. KEYWORDS: fire whirl, radiation, centerline velocity, burning rate, pool fires. NOMENCLATURE LISTING

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Reconstruction of fire whirls using scale models

Cited by 128 publications

References 9 publications

Flow Structure Of A Fixed-frame Type Firewhirl

Flow Structure Of A Fixed-frame Type Firewhirl

Simulations Of Swirling Fires Controlled By Channeled Self-generated Entrainment Flows

Experimental Research on Burning Rate, Vertical Velocity and Radiation of Medium-Scale Fire Whirls

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