scholarly journals Observation on a fire whirl in a vertical shaft using high-speed camera and associated correlation derived

2019 ◽  
pp. 266-266
Author(s):  
Hing Hung ◽  
Shousuo Han ◽  
Wan Chow ◽  
Cheuk Chow
Keyword(s):  
Burning Rate ◽  
High Speed ◽  
Tall Buildings ◽  
Burning Surface ◽  
Air Entrainment ◽  
Pool Fire ◽  
Flame Height ◽  
Vertical Shaft ◽  
High Speed Camera ◽  
Fire Whirl

The fire whirl generated by burning a pool fire in a vertical shaft with a single corner gap of appropriate width was studied using a high-speed camera. A 7-cm diameter pool propanol fire with heat release rate 1.6 kW in free space was burnt inside a 145-cm tall vertical shaft model with gap widths lying between 2 cm and 16 cm. The flame height was between 0.25 m and 0.85 m for different gap widths. Photographs taken using a high-speed camera at critical times of swirling motion development were used to compare with those taken using a normal camera. From the experimental observations on flame swirling by a high-speed camera, stages for generating the fire whirl were identified much more accurately. Two flame vortex tubes moving over the horizontal burning surface of the liquid pool were observed. Based on these observations a set of more detailed schematic diagrams on the swirling motion was constructed. From the observed flame heights under different gap widths and using three assumptions on the variation of air entrainment velocity with height, an empirical expression relating the burning rate with flame height and the corner gap width was derived from the observation with high-speed camera. The correlation expression of the burning rate of the pool fire obtained would be useful in fire safety design in vertical shafts of tall buildings.

A study of correlation between flame height and gap width of an internal fire whirl in a vertical shaft with a single corner gap

2017 ◽  
Vol 28 (1) ◽  
pp. 34-45 ◽  
Author(s):  
G. W. Zou ◽  
H. Y. Hung ◽  
W. K. Chow
Keyword(s):  
Experimental Data ◽  
Fire Safety ◽  
Air Entrainment ◽  
Pool Fire ◽  
Flame Height ◽  
Vertical Shaft ◽  
Entrainment Velocity ◽  
Fire Safety Design ◽  
Fire Whirl ◽  
Gap Width

An internal fire whirl can be generated by a pool fire burning in a vertical shaft with a single corner gap of appropriate width. In an internal fire whirl, the flame height is an important characteristic in terms of fire safety. In this paper, a correlation expression of flame height with the width of a single corner gap was studied using reported experimental data in a 9-m tall vertical shaft model. A pool of gasoline fuel was burnt inside the shaft model to study the characteristics of flame swirling. An internal fire whirl was generated for gap widths lying between 0.11 m and 0.66 m, when the pool fire was 0.46 m diameter. The flame height was between 2.5 m and 3.2 m. From the experimental observations on flame swirling for different gap widths, coupled with three assumptions on variation of air entrainment velocity with height, an expression relating the flame height and the corner gap width was derived for the internal fire whirl using a set of compiled experimental data. The correlation expression obtained would be useful for fire safety design in vertical shafts.

scholarly journals Interactive Effects in Two-Droplets Combustion of RP-3 Kerosene under Sub-Atmospheric Pressure

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1229
Author(s):  
Hongtao Zhang ◽  
Zhihua Wang ◽  
Yong He ◽  
Jie Huang ◽  
Kefa Cen
Keyword(s):  
Burning Rate ◽  
Atmospheric Pressure ◽  
High Speed ◽  
Ambient Pressure ◽  
Interactive Effects ◽  
Propagation Time ◽  
High Speed Camera ◽  
Single Droplet ◽  
Fuel Droplets ◽  
Spacing Distance

To improve our understanding of the interactive effects in combustion of binary multicomponent fuel droplets at sub-atmospheric pressure, combustion experiments were conducted on two fibre-supported RP-3 kerosene droplets at pressures from 0.2 to 1.0 bar. The burning life of the interactive droplets was recorded by a high-speed camera and a mirrorless camera. The results showed that the flame propagation time from burning droplet to unburned droplet was proportional to the normalised spacing distance between droplets and the ambient pressure. Meanwhile, the maximum normalised spacing distance from which the left droplet can be ignited has been investigated under different ambient pressure. The burning rate was evaluated and found to have the same trend as the single droplet combustion, which decreased with the reduction in the pressure. For every experiment, the interactive coefficient was less than one owing to the oxygen competition, except for the experiment at L/D0 = 2.5 and P = 1.0 bar. During the interactive combustion, puffing and microexplosion were found to have a significant impact on secondary atomization, ignition and extinction.

Some Experimental Results on Internal Fire Whirls in a Vertical Shaft

2013 ◽  
Author(s):  
Y. Gao ◽  
G. W. Zou ◽  
S. S. Li ◽  
W. K. Chow
Keyword(s):  
Full Scale ◽  
Pool Fire ◽  
Experimental Results ◽  
Vertical Shaft ◽  
Remote Site ◽  
Scale Modeling ◽  
Key Factor ◽  
Fire Whirl ◽  
Real Scale

Earlier studies on burning a pool fire in a vertical shaft model indicated that appropriate sidewall ventilation provision is a key factor for the onset of an internal fire whirl. Experiments on burning a pool fire inside a real-scale shaft model of 9 m tall were performed to further investigate the swirling motion. The full-scale modeling burning tests were carried out at a remote site in China. Four different ventilation openings were arranged. Results of onsetting of internal fire whirls for the four tests will be reported.

An experimental investigation of the flame height and air entrainment of ring pool fire

Fuel ◽  
2018 ◽  
Vol 216 ◽  
pp. 734-737 ◽  
Author(s):  
Changfa Tao ◽  
Yongqiang Liu ◽  
Fei Tang ◽  
Qiang Wang
Keyword(s):  
Experimental Investigation ◽  
Air Entrainment ◽  
Pool Fire ◽  
Flame Height

scholarly journals Soot Volume Fraction Measurements by Auto-Compensating Laser-Induced Incandescence in Diffusion Flames Generated by Ethylene Pool Fire

2021 ◽  
Vol 7 ◽  
Author(s):  
Juan J. Cruz ◽  
Ignacio Verdugo ◽  
Nicolás Gutiérrez-Cáceres ◽  
Felipe Escudero ◽  
Rodrigo Demarco ◽  
...  
Keyword(s):  
Burning Rate ◽  
Volume Fraction ◽  
Soot Volume Fraction ◽  
Air Entrainment ◽  
Pool Fire ◽  
Mass Burning Rate ◽  
Data Set ◽  
Pool Surface ◽  
Laser Induced Incandescence ◽  
Radiation Feedback

The main characteristics of pool fire flames are flame height, air entrainment, pulsation of the flame, formation and properties of soot particles, mass burning rate, radiation feedback to the pool surface, and the amount of pollutants including soot released to the environment. In this type of buoyancy controlled flames, the soot content produced and their subsequent thermal radiation feedback to the pool surface are key to determine the self-sustainability of the flame, their mass burning rate and the heat release rate. The accurate characterization of these flames is an involved task, specially for modelers due to the difficulty of imposing adequate boundary conditions. For this reason, efforts are being made to design experimental campaigns with well-controlled conditions for their reliable repeatability, reproducibility and replicability. In this work, we characterized the production of soot in a surrogate pool fire. This is emulated by a bench-scale porous burner fueled with pure ethylene burning in still air. The flame stability was characterized with high temporal and spatial resolution by using a CMOS camera and a fast photodiode. The results show that the flame exhibit a time-varying propagation behavior with a periodic separation of the reactive zone. Soot volume fraction distributions were measured at nine locations along the flame centerline from 20 to 100 mm above the burner exit using the auto-compensating laser-induced incandescence (AC-LII) technique. The mean, standard deviation and probability density function of soot volume fraction were determined. Soot volume fraction presents an increasing tendency with the height above the burner, in spite of a local decrease at 90 mm which is approximately the position separating the lower and attached portion of the flame from the higher more intermittent one. The results of this work provide a valuable data set for validating soot production models in pool fire configurations.

Internal Fire Whirls Induced by Pool Fire in a Vertical Shaft

2011 ◽  
Author(s):  
Yan Huo ◽  
W. K. Chow ◽  
Ye Gao
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
Air Flow ◽  
Pool Fire ◽  
Vertical Shaft ◽  
Pool Fires ◽  
Key Factor ◽  
Fire Whirl ◽  
Gap Width

Internal fire whirls induced by a pool fire in a square vertical shaft were studied by experiments and numerical simulations. The burning behaviour of two pool fires in the vertical shaft and in open air was compared. The gap width of the rig is a key factor in onsetting fire whirls. Air flow field in the vertical square shaft of different gap widths were studied experimentally with nine tests. A fire whirl would not be onsetted when the gap is too narrow nor too wide. Whirling flame is not clearly observed near to the bottom of the vertical shaft when the gap width was small.

scholarly journals The Effect of Nitrogen on Flame Characteristics in Biogas External Premixed Combustion

2016 ◽  
Vol 836 ◽  
pp. 265-270 ◽  
Author(s):  
Willyanto Anggono ◽  
Fandi Dwiputra Suprianto ◽  
Kenny Purnomo ◽  
Tan Ivan Hartanto ◽  
Tubagus P. Wijaya
Keyword(s):  
Carbon Dioxide ◽  
High Speed ◽  
Premixed Combustion ◽  
Flame Height ◽  
High Speed Camera ◽  
Fluid Supply ◽  
Bacterial Action ◽  
Fuel Mixtures ◽  
External Combustion ◽  
Flame Angle

Biogas contains more than 50% methane (CH4), is a renewable and eco-friendly fuel produced by bacterial action. Not only is biogas flammable but it also contains inhibitors like carbon dioxide and nitrogen, as well as small amounts of H2, O2, H2S and others. Several associated studies have been conducted in order to examine biogas combustion characteristics in external combustion and flame angle, flame height and dimensionless flame height are the important characteristics in external premixed combustion. This research’s aims were to discover the influences of N2 as it is the second most prevalent inhibitor in biogas by burning stoichiometric fuel mixtures (CH4 and N2 (0%-50% of fuel)) and oxygen in an experimental external premixed combustion burner whose nozzle tip diameter was 5 mm. The burner was connected to a hose from the oxygen tank and another hose from the fuel tank. Two regulators and flowmeters were placed on each tank to monitor the flow supplied to the mixer and burner. The valves were used to stop or open the fluid supply. The outcome flame propagation is then recorded by a high speed camera and then processed through a computer system. The results indicate that N2 influenced the flame angle, flame height and dimensionless flame height. The higher the N2 content inside the fuel, the shorter the flame height and the lower the dimensionless flame height. Moreover, increasing the N2 content created larger the flame angle.

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