Numerical simulation on temperature in wood crib fires

Xi, Yang; Dong, Xue; Chow, Wan Ki

doi:10.2298/tsci180818288x

Cited by 3 publications

(2 citation statements)

References 19 publications

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“…The excavation roadway in the mine is a semiclosed type, and the excavation face uses a local press-in ventilation system. The airflow is in the form of a limited adherent jet, which can mix smoke in the enclosed space, making the smoke migration more complex [40,41]. In this section, the effect of local ventilation on smoke movement and temperature characteristics in an excavation roadway in 150 s is analyzed.…”

Section: Numerical Simulation Of the Influence Of Local Ventilation O...mentioning

confidence: 99%

Study on the Temperature and Smoke Movement in the Event of a Fire in a Semiclosed Tunnel under Water Spray

Li,

Zhang,

et al. 2023

Fire

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Semiclosed tunnels are very common in engineering construction. They are not connected, so they easily accumulate heat. Once a fire breaks out in a semiclosed tunnel, the route for rescue workers to enter is limited, so it is tough to get close to the fire source. In this paper, taking a mine excavation roadway with local pressure ventilation as an example, the temperature field distribution and water spray fire prevention characteristics of the excavation roadway face were studied using numerical simulation and theoretical analysis. This paper provides an explanation of a dynamics-based smoke management method for water spraying in a semiclosed tunnel as well as the equilibrium relationship between droplet drag force and smoke buoyancy. A method was first developed to calculate the quantity of smoke blockage based on the thickness of the smoke congestion. The local ventilation and smoke movement created a circulating flow in the excavation face, which was discovered by investigating the velocity and temperature fields of the excavation face. The size of the high-temperature area and the pattern of temperature stratification varied due to this circulating flow. When local ventilation and sprinkler systems were operating simultaneously, when the volume of smoke was small, the smoke avoided the majority of the water spray effect with the circulation flow; however, when the volume of smoke was large, the effect of the circulation flow decreased and the smoke gathered close to the sprinkler head. At this time, the blocking effect of the water spray was significant. The mean square error analysis revealed that activating the sprinkler had the most significant cooling impact on the wall on one side of the air duct.

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Section: Numerical Simulation Of the Influence Of Local Ventilation O...mentioning

confidence: 99%

Study on the Temperature and Smoke Movement in the Event of a Fire in a Semiclosed Tunnel under Water Spray

Li,

Zhang,

et al. 2023

Fire

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“…Since pyrolysis is an integral part of forest fuel (FF) combustion, its study is expedient with the view of development of mathematical models necessary to elaborate the existing and create the new technologies for suppression of flaming combustion and smoldering [1,2] in effective fire control. To date, the analysis of thermokinetic characteristics of plant materials (mainly, different types of wood) is investigated in numerous papers, among which several of the most significant may be distinguished, in particular [3][4][5][6][7][8]. Research [3] proposed the model, used in the analysis of conditions of the Mediterranean forest fire development.…”

Section: Introductionmentioning

confidence: 99%

Influence of particle size and density of pelleted samples of forest fuel on thermokinetic characteristics of pyrolysis and oxidation

et al. 2021

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This paper presents the results of experimental studies of thermokinetic characteristics of pyrolysis and oxidation of pine needles, taking into account the influence of particle size and density of forest fuel in pelleted samples. The sample densities range within 206-955 kgm-3 (i.e. from typical sample densities to average ones for pressed pelleted samples), and the component particle sizes amount to 60-140 ?m. The range of studied temperatures is 20-1000 o?. The particle size and density of the material are found to be important parameters that significantly affect the kinetics of pyrolysis. According to the results of measurements, the activation energy of needles pyrolysis is within the range of 22.8-113.8 kJmol-1, and that of oxidation corresponds to 134.7-211 kJmol-1. Three intervals with significantly different values of activation energy and pre-exponential factor are distinguished in the studied temperature range. Approximation expressions are formulated for the activation energies of pyrolysis and oxidation as functions of forest fuel particle sizes, sample density and temperature.

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Discussion of thermal activation on heat collection plate of sprinkler heads

Szeto,

Wu,

Chow

et al. 2024

THERM SCI

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Heat collection plates (HCP) are installed above sprinkler heads in some tall halls in the Asia-Oceania region to give faster thermal actuation. In this study, experiments were thus conducted in a fire chamber to determine thermal activation times of sprinkler heads with and without HCP. Three HCPs with different diameters were selected and tested with pendent fast response liquid-in-bulb sprinkler heads. A total of 48 sprinklers heads were studied under different conditions of height and pool fire size. HCP was found to reduce sprinkler activation time in a fire chamber test by up to 61%. Thermal activation time of sprinkler heads was also investigated by the common plunge test in a wind tunnel. Results indicate that activation was delayed by 5%, 18% and 221% on average by the three HCPs. An HCP of pie plate shape with small diameter would alter the physical scenario of heating up the heat sensing element of sprinkler heads assumed in the plunge test. Therefore, the effect of HCP cannot be appropriately assessed in a wind tunnel.

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Numerical simulation on temperature in wood crib fires

Cited by 3 publications

References 19 publications

Study on the Temperature and Smoke Movement in the Event of a Fire in a Semiclosed Tunnel under Water Spray

Study on the Temperature and Smoke Movement in the Event of a Fire in a Semiclosed Tunnel under Water Spray

Influence of particle size and density of pelleted samples of forest fuel on thermokinetic characteristics of pyrolysis and oxidation

Discussion of thermal activation on heat collection plate of sprinkler heads

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