Experimental and Theoretical Study for Tunnel Fires with Natural Ventilation

Yuan, Zhongyuan; Lei, Bo; Kashef, Ahmed

doi:10.1007/s10694-013-0378-x

Cited by 45 publications

(11 citation statements)

References 16 publications

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“…Wang et al [11] proposed a method for calculating the mass flow rate of the shaft under the conditions of plug phenomenon and no plug phenomenon. Yuan et al [12] used small-scale experiments combined with theoretical analysis to study the plug phenomenon, and proposed a prediction model to predict the distribution of the tunnel ceiling's smoke temperature and the shafts' smoke exhaust efficiency, which concludes shaft size and shaft spacing. He et al [13] studied the influence of shaft height and fire source heat release rate (HRR) on the smoke exhaust efficiency of the shaft in the 1:10 tunnel model, and found that as the shaft height increases, the smoke exhaust efficiency of the shaft first decreases and then increase.…”

Section: Intruductionmentioning

confidence: 99%

Numerical study on the effect of shaft position on natural smoke exhaust in tunnels with one closed portal

et al. 2020

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.This paper uses Fire Dynamics Simulator (FDS) to study the effect of the longitudinal distance from the shaft to the fire source on the natural smoke exhaust of the tunnel fire with one closed portal, and analyzes the temperature distribution of the smoke and the shaft’s smoke exhaust efficiency. The results show that when the shaft is located downstream of the fire source (Ds<0), with the increase of the distance from the shaft to the fire source, the smoke exhaust efficiency decreases first and then stabilizes at a fixed value. At this time, the ceiling temperature attenuation’s coefficient at upstream of the fire source is only related to the heat release rate of the fire source (HRR). When the shaft is located upstream of the fire source (Ds>0), the smoke exhaust efficiency increases slightly with the increase of the distance from the shaft to the fire source, but the overall value is relatively small. When HRR is fixed, the shaft located downstream of the fire source has a higher smoke exhaust efficiency. As the distance between the shaft and the fire source increases, the plug phenomenon decreases.

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Section: Intruductionmentioning

confidence: 99%

Numerical study on the effect of shaft position on natural smoke exhaust in tunnels with one closed portal

et al. 2020

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“…To analyze and calculate the ceiling temperature distribution, a dimensionless temperature rise is adopted from the reference [28], as shown in Equation (6).…”

Section: Temperature Distribution Below the Ceilingmentioning

confidence: 99%

A Study on Ceiling Temperature Distribution and Critical Exhaust Volumetric Flow Rate in a Long-Distance Subway Tunnel Fire with a Two-Point Extraction Ventilation System

Zhao

Yuan

et al. 2019

Energies

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Smoke control is a crucial issue in a long-distance subway tunnel fire, and a two-point extraction ventilation system is an effective way to solve this problem, due to the characteristics of controlling the smoke in a limited area and removing high-temperature and toxic smoke in time. In this study, the ceiling temperature distribution and the critical exhaust volumetric flow rate to control the smoke in the zone between two extraction vents were investigated in a long-distance subway tunnel fire with a two-point extraction ventilation system. Experiments were carried out in a 1/20 reduced-scale tunnel model based on Froude modeling. Factors, including the heat release rate (HRR), the extraction vent length, the internal distance between two extraction vents and exhaust volumetric flow rate, were studied. Smoke temperature below the ceiling, exhaust volumetric flow rate and smoke spreading configurations were measured. The ceiling temperature distribution was analyzed. Meanwhile, an empirical equation was developed to predict the critical exhaust volumetric flow rate based on the one-dimensional theory, experimental phenomenon and the analysis of forces acting at the smoke underneath the extraction vent. The coefficients in the empirical equation were determined by experimental data. Compared with the experimental results, the developed empirical equation can predict the critical exhaust volumetric flow rate well. Research outcomes in this study will be beneficial to the design and application of two-point extraction ventilation system for a long-distance subway tunnel fire.

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“…The distribution of smoke in railway tunnels under natural ventilation mode was investigated in a 1:15 model-scale tunnel, and the corresponding empirical formula was derived. The formula could be used to predict ceiling temperature distribution and smoke exhaust [23]. The tunnel fire smoke exhaust system under the coupling of longitudinal ventilation and shaft mechanical smoke exhaust was investigated through a scaled (1:5) model; this combined method was beneficial to smoke exhaust and evacuation [24].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on the Discharge of Pollutants from Tunnel Fires

Zhai

Nong

et al. 2020

Sustainability

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Many pollutants are generated during tunnel fires, such as smoke and toxic gases. How to control the smoke generated by tunnel fires was focused on in this paper. A series of experiments were carried out in a 1:10 model tunnel with dimensions of 6.0 m × 1.0 m × 0.7 m. The purpose was to investigate the smoke layer thickness and the heat exhaust coefficient of the tunnel mechanical smoke exhaust mode under longitudinal wind. Ethanol was employed as fuel, and the heat release rates were set to be 10.6 kW, 18.6 kW, and 31.9 kW. The exhaust velocity was 0.32–3.16 m/s, and the longitudinal velocity was 0–0.47 m/s. The temperature profile in the tunnel was measured, and the buoyant flow stratification regime was visualized by a laser sheet. The results showed that the longitudinal ventilation leads to a secondary stratification of the smoke flow. In the ceiling extract tunnel under longitudinal ventilation, considering the research results of the smoke layer height and the heat exhaust coefficient, a better scheme for fire-producing pollutants was that an exhaust velocity of 1.26–2.21 m/s (corresponding to the actual velocity of 4.0–7.0 m/s) should be used. The longitudinal velocity should be 0.16–0.32 m/s (corresponding to the actual velocity of 0.5–1.0 m/s).

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Experimental and Theoretical Study for Tunnel Fires with Natural Ventilation

Cited by 45 publications

References 16 publications

Numerical study on the effect of shaft position on natural smoke exhaust in tunnels with one closed portal

Numerical study on the effect of shaft position on natural smoke exhaust in tunnels with one closed portal

A Study on Ceiling Temperature Distribution and Critical Exhaust Volumetric Flow Rate in a Long-Distance Subway Tunnel Fire with a Two-Point Extraction Ventilation System

Experimental Investigation on the Discharge of Pollutants from Tunnel Fires

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