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 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.

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.

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 A Simplified Method for Establishing Safe Available Evacuation Time Based on a Descending Smoke Layer 

2018 ◽  
Vol 20 (2) ◽  
pp. 28-34
Author(s):  
Jiri Pokorny ◽  
Vladimir Mozer ◽  
Lenka Malerova ◽  
Dagmar Dlouha ◽  
Peter Wilkinson
Keyword(s):  
Fire Safety ◽  
Air Entrainment ◽  
New Method ◽  
Fire Growth ◽  
Design Standards ◽  
Evacuation Time ◽  
Wide Range ◽  
Safety Design ◽  
Smoke Layer ◽  
Fire Safety Design

Keeping the smoke layer at a safe height is one of the most important tenability criteria in assessment of evacuation from buildings. The basis of this approach is an accurate approximation of the fire and smoke plume, which is formed above the fire source. The major variables affecting smoke filling are the fire growth rate and enclosure geometry, i.e. the floor area and height. This paper deals with the implementation of a new method for establishing safe available evacuation time based on the fundamental principles of smoke generation and flow into the national fire safety design standards in the Czech and Slovak Republic. Some of these calculation methods have also been included in fire safety engineering ISO standards. The devised method is based on the t-squared fire growth model and correlations for smoke production and air entrainment into the rising plume of smoke. Subsequently, the proposed method is validated against a wide range of benchmark scenarios in the two-zone fire model CFAST. The paper compares the differences, comments on their causes and evaluates the applicability of the new method in both countries. The proposed method is not only compatible with the national fire safety design standards, but also allows for a more precise assessment of life safety without the need for overly complicated calculations.

Sign in / Sign up

Export Citation Format

Share Document