Effect Of Cross-Winds To Apparent Flame Height And Tilt Angle From Several Kinds Of Fire Source

Oka, Y.; Sugawa, Osami; Imamura, Tomohiko; Matsubara, Yoshiyuki

doi:10.3801/iafss.fss.7-915

Cited by 58 publications

(13 citation statements)

References 14 publications

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“…Because the

{\dot{Q}}_{r}^{*}

indicates the thermophysical property of fuel, it is believed that the

{\dot{Q}}_{r}^{*}

is still appropriate for the crosswind situation. In addition, Oka et al proposed that tanθ is also related to the Froude number, and it represents a characteristic of inertia force of the wind cross. Furthermore, the tilt angle is coupled with the position of the pool in the above flame image.…”

Section: Resultsmentioning

confidence: 99%

“…Oka et al 23 proposed the following empirical formula to characterize the flame length and tilt angle by using a rectangular propane gas burner…”

Section: Discussionmentioning

confidence: 99%

“…Oka et al proposed the following empirical formula to characterize the flame length and tilt angle by using a rectangular propane gas burner

((), l_{f} / w) ((), D / L) = λ {({italicFr}^{2 / 3} / {\overset{Q}{true}}_{r}^{*})}^{β},

tan θ = {Fr}^{2 / 5} {\dot{Q}}_{r}^{* - 0.1 ((), 1 + 2.5 φ)} {(L / D)}^{- 0.5},

where the Froude number

italicFr = u_{0}^{2} / italicgw

; w is the windward side length of the rectangular pool; L is the length of long side of the rectangular pool; λ , β , and φ are empirical parameters; and

{\dot{Q}}_{r}^{*}

is the dimensionless heat release rate for the rectangular pool

{\dot{Q}}_{r}^{*} = \frac{Q_{s}}{ρ_{\infty} C_{p} T_{a} \sqrt{g} {LW}^{\frac{3}{2}}} .

On the basis of Formula , the semiempirical formula of flame tilt for rectangular hydrocarbon pool fires with crosswind in a reduced‐pressure atmosphere at high altitude was studied by Tang et al It is believed that the proportionality coefficient is high in a low‐pressure environment and vice versa.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The effects of transient heat release rate and crosswind on flame length and tilt angle of flames at different positions in the spread of fire over a diesel pool

Wang

Dong

et al. 2018

Fire and Materials

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Summary The spread of fire over liquid fuel is a common phenomenon, and it has been demonstrated experimentally that the flame length and tilt angle change with the transient heat release rate and different positions of the flame. The coupling relationship between these factors is studied in this paper. The experiments are composed of a rectangular pool with dimensions of 80 cm × 6 cm × 5 cm and crosswind with speeds of 0.8 to 2.4 m/s. Diesel is used as the fuel, and a new method is applied to ensure that the initial temperature of the diesel is constant during ignition. The results show that the traditional method of luminous flame intermittency may not be suitable for studying the geometric characteristics of the spread of fire over a pool, and a new method is proposed. In addition, the transient variation of flame length in different positions of the pool is shown to fluctuate around a mean flame length. The evolution of flame tilt angle along the longitudinal direction of the pool exhibits a U‐shaped curve. Moreover, the multivariate nonlinear relationships of mean flame length and tilt angle among the heat release rate, fire position, and wind speed are established, and relevant coefficients are determined.

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“…Because the

{\dot{Q}}_{r}^{*}

indicates the thermophysical property of fuel, it is believed that the

{\dot{Q}}_{r}^{*}

Section: Resultsmentioning

confidence: 99%

“…Oka et al 23 proposed the following empirical formula to characterize the flame length and tilt angle by using a rectangular propane gas burner…”

Section: Discussionmentioning

confidence: 99%

“…Oka et al proposed the following empirical formula to characterize the flame length and tilt angle by using a rectangular propane gas burner

((), l_{f} / w) ((), D / L) = λ {({italicFr}^{2 / 3} / {\overset{Q}{true}}_{r}^{*})}^{β},

tan θ = {Fr}^{2 / 5} {\dot{Q}}_{r}^{* - 0.1 ((), 1 + 2.5 φ)} {(L / D)}^{- 0.5},

where the Froude number

italicFr = u_{0}^{2} / italicgw

; w is the windward side length of the rectangular pool; L is the length of long side of the rectangular pool; λ , β , and φ are empirical parameters; and

{\dot{Q}}_{r}^{*}

is the dimensionless heat release rate for the rectangular pool

{\dot{Q}}_{r}^{*} = \frac{Q_{s}}{ρ_{\infty} C_{p} T_{a} \sqrt{g} {LW}^{\frac{3}{2}}} .

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The effects of transient heat release rate and crosswind on flame length and tilt angle of flames at different positions in the spread of fire over a diesel pool

Wang

Dong

et al. 2018

Fire and Materials

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“…Shear-stresses between hot combustion products and fresh air make the flow unstable and amplify oscillations near the fire base due to large eddy structures corresponding to hot gases puffs burning [31]. Coherent structures appear also surrounding the wing, and the flame presents a pronounced instability due to crosswind, following the experimental observation [8][9][10][11].…”

Section: Heat Flux Distributionmentioning

confidence: 99%

Impact of a Change from an Aluminium- to a Composite-Type Aircraft on Wind-Assisted Aviation-Fuel Fire Dynamics - a Numerical Study

Hy¹,

Wang²

2020

J Aerosp Eng Mech

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This numerical study focuses on the impact of a composite-type aircraft on a large aviation-fuel fire in a moving fluid medium. A pyrolysis model over surface of condensed fuel and composite material is incorporated, allowing to investigate the roles of the wind conditions on fire growth, heat flux distribution and smoke products. The outcome of the study indicates that interaction between composite-type aircraft and fire environment combined with the influence of wind conditions affects dramatically the continuous flame shape and consequently, the distribution of the incident heat fluxes to the engulfed fuselage. An increase of wind speed results in an alteration of flame cover where the fire and fuselage are of comparable size. The highest toxic products such as carbon monoxide and soot occur on the windward side of the fuselage for a low wind speed, but on the leeward side of the fuselage for a medium or high wind one. The flame spread rate over a composite-type aircraft is almost equal in magnitude for a medium or high wind speed, but about a factor 4 increase of that to the low wind one. As a consequence, the fire power from a composite-type aircraft represents an increase of about 30% in comparison with that from aluminium-type one with a wind speed above 5 m/s.

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“…The variations in flame geometry in fires subjected to cross-flow have been studied both experimentally (Putnam 1965;Oka et al 2000;Oka et al 2003;Cole et al 2011;Hu et al 2013;Lam and Weckman 2015) and numerically (Albini 1981;Sinai and Owens 1995;Morvan et al 1998;Porterie et al 2000;Morvan et al 2001;Nmira et al 2010;Vasanth et al 2013) over the past several decades. However, past experimental studies typically use a limited range of diagnostics, primarily video imaging and temperature measurements, while past numerical studies typically use low-order approaches, for instance Reynolds-Averaged Navier-Stokes simulations (Sinai and Owens 1995;Morvan et al 1998;Porterie et al 2000;Morvan et al 2001;Nmira et al 2010;Vasanth et al 2013), that do not resolve the relevant turbulent flow and flame scales.…”

mentioning

confidence: 99%

A study of the structure of a turbulent line fire subjected to cross-flow using large eddy simulations

Trouvé¹,

Verma²

Advances in Forest Fire Research 2018

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Effect Of Cross-Winds To Apparent Flame Height And Tilt Angle From Several Kinds Of Fire Source

Cited by 58 publications

References 14 publications

The effects of transient heat release rate and crosswind on flame length and tilt angle of flames at different positions in the spread of fire over a diesel pool

The effects of transient heat release rate and crosswind on flame length and tilt angle of flames at different positions in the spread of fire over a diesel pool

Impact of a Change from an Aluminium- to a Composite-Type Aircraft on Wind-Assisted Aviation-Fuel Fire Dynamics - a Numerical Study

A study of the structure of a turbulent line fire subjected to cross-flow using large eddy simulations

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