Effect on Radiant Heat Transfer at the Surface of a Pool Fire Interacting With a Water Mist

2009 ◽  
Vol 132 (2) ◽  
Author(s):  
J. P. Garo ◽  
J. P. Vantelon ◽  
D. Lemonnier
Keyword(s):  
Magnitude Estimate ◽  
Radiant Heat ◽  
Water Mist ◽  
Flame Stabilization ◽  
Pool Fire ◽  
Heat Extraction ◽  
Small Scale ◽  
Attractive Alternative ◽  
Radiant Heat Transfer ◽  
Order Of Magnitude

It is well established that the use of water mist can be an attractive alternative to gaseous suppression agents to extinguish fires for specific scenarios. Among the main mechanisms, which act together to extinguish fires when using a water mist: heat extraction, oxygen displacement, and radiant heat attenuation, the last one has received the less attention, especially regarding the energy balance at the fuel surface and, therefore, the rate of generation of flammable vapors. The objective of this work is to analyze, on the one hand, the perturbing influence of a mist addition as an opposed flow to a small-scale liquid (heptane) pool fire structure, especially at its base, the more interesting zone regarding the mechanisms of flame stabilization and extinction and, on the other hand, the effect on the surface radiant heat feedback. Experiments conducted give an order of magnitude estimate in essential agreement with a radiation computation, based on the mappings, previously obtained, of the two major parameters: temperature and extinction coefficient, that determine the thermal radiation of the flame. The important information is the confirmation that radiation attenuation cannot be identified as a predominant mechanism of extinguishment.

Addition of a water mist on a small-scale liquid pool fire: Effect on radiant heat transfer at the surface

2002 ◽  
Vol 29 (1) ◽  
pp. 377-384 ◽  
Author(s):  
J. Richard ◽  
J.P. Garo ◽  
J.M. Souil ◽  
J.P. Vantelon ◽  
D. Lemonnier
Keyword(s):  
Heat Transfer ◽  
Radiant Heat ◽  
Water Mist ◽  
Liquid Pool ◽  
Pool Fire ◽  
Small Scale ◽  
Radiant Heat Transfer ◽  
Fire Effect

Numerical Simulation and Research of Pool Fire Suppressed by Water Mist in the Engineroom of a Ship

2010 ◽  
Vol 29-32 ◽  
pp. 651-657 ◽  
Author(s):  
Jian He Zhao ◽  
Ye Gao ◽  
Hong Mei Wu
Keyword(s):  
Numerical Simulation ◽  
Oxygen Content ◽  
Large Scale ◽  
Cone Angle ◽  
Water Mist ◽  
Fire Fighting ◽  
Pool Fire ◽  
Cooling Effect ◽  
Small Scale ◽  
Spray Cone

Ship engineroom fire is one of the most common and serious disasters in shipwrecks. It has become a hotspot of research to use water mist system to extinguish engineroom fire efficiently in the ship fire fighting field. In this paper, using Fluent to simulate water mist suppressing engineroom fire on the conditions of different fire scales, droplet diameters, spray cone angles and spray pressures. Research indicates that: large scale fires are more easily suppressed than small scale fires by water mist in the enclosure engineroom; the droplets of water mist should be neither too big nor too small, or else it would go against fire fighting. It is pointed out that the droplets should be in the range of 200 μm to 400 μm; the smaller cone angle nozzle can guarantee a high flame cooling effect; the increase of spray pressure can enhance the flame cooling effect, but probably of only marginal help in reducing the oxygen content.

EXPERIMENTAL STUDY ON EXTINGUISHING POOL FIRE SHELTERED BY BARRIER WITH WATER MIST

2004 ◽  
Vol 12 (3) ◽  
pp. 209-222
Author(s):  
LIU JIANGHONG ◽  
FANG YUDONG ◽  
LIAO GUANGXUAN ◽  
LIN LIN
Keyword(s):  
Experimental Study ◽  
Water Mist ◽  
Pool Fire

scholarly journals Effects of Discharge Area and Atomizing Gas Type in Full Cone Twin-Fluid Atomizer on Extinguishing Performance of Heptane Pool Fire under Two Heat Release Rate Conditions in an Enclosed Chamber

2021 ◽  
Vol 11 (7) ◽  
pp. 3247
Author(s):  
Dong Hwan Kim ◽  
Chi Young Lee ◽  
Chang Bo Oh
Keyword(s):  
Heat Release ◽  
Flow Rate ◽  
Heat Release Rate ◽  
Release Rate ◽  
Water Mist ◽  
Pool Fire ◽  
Sauter Mean Diameter ◽  
Discharge Area ◽  
Fire Extinguishing ◽  
Enclosed Chamber

In this study, the effects of discharge area and atomizing gas type in a twin-fluid atomizer on heptane pool fire-extinguishing performance were investigated under the heat release rate conditions of 1.17 and 5.23 kW in an enclosed chamber. Large and small full cone twin-fluid atomizers were prepared. Nitrogen and air were used as atomizing gases. With respect to the droplet size of water mist, as the water and air flow rates decreased and increased, respectively, the Sauter mean diameter (SMD) of the water mist decreased. The SMD of large and small atomizers were in the range of approximately 12–60 and 12–49 μm, respectively. With respect to the discharge area effect, the small atomizer exhibited a shorter extinguishing time, lower peak surface temperature, and higher minimum oxygen concentration than the large atomizer. Furthermore, it was observed that the effect of the discharge area on fire-extinguishing performance is dominant under certain flow rate conditions. With respect to the atomizing gas type effect, nitrogen and air appeared to exhibit nearly similar extinguishing times, peak surface temperatures, and minimum oxygen concentrations under most flow rate conditions. Based on the present and previous studies, it was revealed that the effect of atomizing gas type on fire-extinguishing performance is dependent on the relative positions of the discharged flow and fire source.

scholarly journals A two-dimensional glacier–fjord coupled model applied to estimate submarine melt rates and front position changes of Hansbreen, Svalbard

2018 ◽  
Vol 64 (247) ◽  
pp. 745-758 ◽  
Author(s):  
E. DE ANDRÉS ◽  
J. OTERO ◽  
F. NAVARRO ◽  
A. PROMIŃSKA ◽  
J. LAPAZARAN ◽  
...  
Keyword(s):  
Coupled Model ◽  
Small Scale ◽  
Two Dimensional ◽  
Time Step ◽  
Software Packages ◽  
Front Position ◽  
Circulation Patterns ◽  
Glacier Front ◽  
Order Of Magnitude ◽  
Frontal Ablation

ABSTRACTWe have developed a two-dimensional coupled glacier–fjord model, which runs automatically using Elmer/Ice and MITgcm software packages, to investigate the magnitude of submarine melting along a vertical glacier front and its potential influence on glacier calving and front position changes. We apply this model to simulate the Hansbreen glacier–Hansbukta proglacial–fjord system, Southwestern Svalbard, during the summer of 2010. The limited size of this system allows us to resolve some of the small-scale processes occurring at the ice–ocean interface in the fjord model, using a 0.5 s time step and a 1 m grid resolution near the glacier front. We use a rich set of field data spanning the period April–August 2010 to constrain, calibrate and validate the model. We adjust circulation patterns in the fjord by tuning subglacial discharge inputs that best match observed temperature while maintaining a compromise with observed salinity, suggesting a convectively driven circulation in Hansbukta. The results of our model simulations suggest that both submarine melting and crevasse hydrofracturing exert important controls on seasonal frontal ablation, with submarine melting alone not being sufficient for reproducing the observed patterns of seasonal retreat. Both submarine melt and calving rates accumulated along the entire simulation period are of the same order of magnitude, ~100 m. The model results also indicate that changes in submarine melting lag meltwater production by 4–5 weeks, which suggests that it may take up to a month for meltwater to traverse the englacial and subglacial drainage network.

Radiant Heat Transfer From Isothermal Dispersions With Isotropic Scattering

1967 ◽  
Vol 89 (4) ◽  
pp. 300-308 ◽  
Author(s):  
R. H. Edwards ◽  
R. P. Bobco
Keyword(s):  
Heat Transfer ◽  
Approximate Solutions ◽  
Radiant Heat ◽  
Second Order ◽  
Isotropic Scattering ◽  
Radiant Heat Transfer ◽  
Approximate Methods ◽  
First Order ◽  
Order Solution ◽  
Radiant Transfer

Two approximate methods are presented for making radiant heat-transfer computations from gray, isothermal dispersions which absorb, emit, and scatter isotropically. The integrodifferential equation of radiant transfer is solved using moment techniques to obtain a first-order solution. A second-order solution is found by iteration. The approximate solutions are compared to exact solutions found in the literature of astrophysics for the case of a plane-parallel geometry. The exact and approximate solutions are both expressed in terms of directional and hemispherical emissivities at a boundary. The comparison for a slab, which is neither optically thin nor thick (τ = 1), indicates that the second-order solution is accurate to within 10 percent for both directional and hemispherical properties. These results suggest that relatively simple techniques may be used to make design computations for more complex geometries and boundary conditions.

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