A global non-dimensional factor characterizing side wall constraint effect on facade flame entrainment and flame height from opening of compartment fires

The present paper studies the moisture effect on upward flame spread over cotton fabric by performing experiments using 0.245 mm thick, 180 cm tall and 10 cm wide sample sheets with moisture content ranging from 0% to 18%. As the moisture content increases, the flame height, pyrolysis height, burnout height, pyrolysis length and spread rate show the same trend, first increasing and then decreasing. The maximum value is observed in the case of the 2% moisture content samples. Furthermore, at an infinite length of fabric fuel, the upward flame propagation would reach an asymptotic steady state with constant pyrolysis length and spread rate. Finally, a higher moisture content corresponds to a lower flame temperature. For upward flame spread, the moisture content has the negative effects of increasing the thermal inertia parameters and reducing the flame temperature and heat feedback; simultaneously, the positive effect is that the moisture can enlarge the flame size and the effective preheating length. The combined effects of positive and negative effects result in the non-monotonous trend in the pyrolysis spread rate.

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“…Hu et al. 23 tracked the vertical temperature distribution by two thermocouple trees with four K-type thermocouples.…”

Section: Methodsmentioning

confidence: 99%

“…The temperature measuring range was 0-1200 C, with an accuracy of AE2.2 C. Tsai 22 recorded the flame temperature during the upward flame propagation using a portable K-type thermocouple. Hu et al 23 tracked the vertical temperature distribution by two thermocouple trees with four K-type thermocouples.…”

Section: Methodsmentioning

confidence: 99%

Experimental study of the non-monotonous moisture effect on upward flame spread over cotton fabric

Gao

Zhu

Hui

et al. 2017

Textile Research Journal

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“…Extensive works [9][10][11][12][13][14][15][16][17][18][19][20][21] have been performed to address the characteristics of such facade flame ejecting behaviors. Yokoi [9] carried out the earliest research on window-ejected buoyant thermal plume characteristics for enclosure fires and established the spill fire plume dimensionless temperature distribution model, in which the compartment size was 0.4 m × 0.4 m × 0.2 m. Oleszkiewicz [10] conducted a series of full-scale experiments with different window dimensions and heat release rates (HRRs).…”

Section: Background and Literature Reviewmentioning

confidence: 99%

“…The effect of opposite building on flame height and heat fluxes upon facade wall was considered [15]. Recently, we conducted experiments to investigate the gas temperature inside the [16,17] and with the effects of opposite vertical facing wall [18], side wall [19], and sloping wall [20]. Meanwhile, the external wind conditions had been studied by Huang et al [21], showing a great influence on the enclosure flame development.…”

Section: Background and Literature Reviewmentioning

confidence: 99%

Heat flux profile upon building facade due to ejected thermal plume from window in a subatmospheric pressure at high altitude

Tang

et al. 2015

Energy and Buildings

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“…, reflecting the total heat loss through wall cT h A T  ). In addition, other studies [22][23][24][25][26] focused on different situations and boundary conditions (such as a facing wall [22], eaves [23], side walls [24], ambient pressure [25] and merging behavior for double openings [14,26]). However, in all previous studies, the elevation of the opening mainly remained at the center of the fire compartment.…”

Section: Introductionmentioning

confidence: 99%

Flame behavior from an opening at different elevations on the facade wall of a fire compartment

Wang

Ding

et al. 2021

Proceedings of the Combustion Institute

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This paper investigates flame ejected from opening at different elevations on the facade wall of a fire compartment. Two reduced-scale experimental models are employed consisting of a cubic fire compartment with one opening and a vertical facade wall. Experiments are conducted by varying the height of the opening and at different heat release rates (HRRs). Results show that the distance of the flame base from the bottom of the opening gradually decreases with increasing opening elevation. The external flame height measured from its base increases firstly, reaches the maximum when the opening is located at approximately half height of the fire compartment and subsequently decreases as the opening moves up. Moreover, the increasing elevation of the opening contributes to decreasing mean critical HRR for flame ejection. The above observations are found to be due to the increased deep sinking of the cold inflow while it is mixing and reacting with hot gases, as the vertical elevation of the opening increases, as supported by the additional computational fluid dynamics (CFD) simulation results. This is an important new observation, because whilst having an opening at elevated locations is common in a compartment fire, it has not been accounted for in previous classic models on ejected flame behavior from opening of a fire compartment. By identifying the similarities and differences of facade flame dynamics as the vertical elevation of the opening varies, a new model is proposed and validated for flame height with characteristic length scales to account for the changes in air inflow and critical heat release rate for flame ejection with opening elevations.

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A global non-dimensional factor characterizing side wall constraint effect on facade flame entrainment and flame height from opening of compartment fires

Cited by 32 publications

References 20 publications

Experimental study of the non-monotonous moisture effect on upward flame spread over cotton fabric

Experimental study of the non-monotonous moisture effect on upward flame spread over cotton fabric

Heat flux profile upon building facade due to ejected thermal plume from window in a subatmospheric pressure at high altitude

Flame behavior from an opening at different elevations on the facade wall of a fire compartment

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