scholarly journals Investigation on smoke temperature distribution in a double-deck tunnel fire with longitudinal ventilation and lateral smoke extraction

2019 ◽  
Vol 13 ◽  
pp. 100375 ◽  
Author(s):  
Xin Zhang ◽  
Zhisheng Xu ◽  
Tianxiao Ni ◽  
Jinzhi Peng ◽  
Jiawei Zeng ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Tunnel Fire ◽  
Longitudinal Ventilation

COMPARISON BETWEEN LONGITUDINAL VENTILATION SYSTEM AND POINT EXTRACTION SYSTEM IN ROAD TUNNEL FIRE SAFETY

2021 ◽  
Vol 77 (1) ◽  
pp. 41-59
Author(s):  
Ti-Sheng HUANG ◽  
Nobuyoshi KAWABATA ◽  
Miho SEIKE ◽  
Masato HASEGAWA ◽  
Futoshi TANAKA ◽  
...  
Keyword(s):  
Fire Safety ◽  
Ventilation System ◽  
Extraction System ◽  
Road Tunnel ◽  
Tunnel Fire ◽  
Longitudinal Ventilation

scholarly journals Heat transfer on simplified pre-period stage of tunnel fire

2019 ◽  
Vol 23 (Suppl. 3) ◽  
pp. 799-808
Author(s):  
Hungwei Liu ◽  
Wei Yao
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Heating Rate ◽  
Theoretical Solution ◽  
Theoretical Equation ◽  
Thermal Engineering ◽  
Transient Temperature ◽  
Tunnel Fire ◽  
Transient Temperature Distribution ◽  
Heat Transfer Theory

Tunnel fire is a part of applied thermal problems. With increase of transient temperature of the tunnel fire on the structure surface (i.e. tunnel lining), the heat transfer from the surface is possibly varying transient temperature distribution within the structure. The transient temperature distribution is also possibly damaging the composition of structure (micro-crack) because of critical damage temperature. Therefore, the transient temperature distribution has a significantly important role on defining mechanical and physical properties of structure and determining thermal-induced damaged region. The damage at pre-period stage of tunnel fire is perhaps more significant than that at the other period stages because of thermal gradient. Consequently, a theoretical model was developed for simplifying complicated thermal engineering during pre-period stage of tunnel fire. A hollow solid model (HSM) in a combination of dimensional analysis and heat transfer theory with Bessel?s Function and Duhamel?s Theorem were employed to verify a theoretical equation for dimensionless transient temperature distribution (DTTD) under linear transient thermal loading (LTTL). Experimental and numerical methods were also adopted to approve the results from this theoretical equation. The heating rate (M) is a primary variable for discussing DTTD on three means. The heating rate of 10.191, 10 and 240?C/min were applied to experimental and numerical studies. The experimental and numerical results are consistent with the theoretical solution, successfully verifying that the theoretical solution can predict the DTTD well in field. This equation can be used for thermal/tunnel engineers to evaluate the damaged region and to obtain the parameters related to DTTD.

scholarly journals 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

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1411 ◽  
Author(s):  
Peng Zhao ◽  
Zhongyuan Yuan ◽  
Yanping Yuan ◽  
Nanyang Yu ◽  
Tao Yu
Keyword(s):  
Temperature Distribution ◽  
Flow Rate ◽  
Empirical Equation ◽  
Ventilation System ◽  
Volumetric Flow Rate ◽  
Subway Tunnel ◽  
Smoke Control ◽  
Long Distance ◽  
Tunnel Fire ◽  
Ceiling Temperature

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.

Effects of transverse fire locations on flame length and temperature distribution in a bifurcated tunnel fire

2021 ◽  
Vol 112 ◽  
pp. 103893
Author(s):  
Zhisheng Li ◽  
Yunji Gao ◽  
Xiaosong Li ◽  
Pengfei Mao ◽  
Yuchun Zhang ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Flame Length ◽  
Tunnel Fire

The Study of the Confinement Velocity in the Longitudinal Ventilation Tunnel Fire

2012 ◽  
Vol 446-449 ◽  
pp. 3665-3669
Author(s):  
Ke Qing Sun ◽  
Hui Yang
Keyword(s):  
Characteristic Parameter ◽  
Experimental Models ◽  
Experimental Results ◽  
Mixed Gas ◽  
Control Effect ◽  
Smoke Control ◽  
Tunnel Fire ◽  
Longitudinal Ventilation ◽  
The Relationship ◽  
Two Sides

For the situation that the smoke exhaust vents are located on both sides of the fire source, critical ventilation velocity is not appropriate to evaluate the smoke control effect. “Confinement velocity” is proposed as the characteristic parameter to study the longitudinal ventilation by O.Vauquelin in this situation. However, there have been few studies on confinement velocity. An experimental study was carried out on two reduced scale tunnel models. The main objective is to analysis the relationship between confinement velocity and fire heat release in this situation. Helium and air in different ratio was used as the smoke, and the "cold smoke" produced by smoke generator was put into the mixed gas in order to measure the length of smoke layer. The experimental models were based on the half tunnel as flow field at two sides of fire is symmetrical. The CFD model was created on the basis of the experiment, and the results were basically accord with the experimental results. It was shown from the experimental results that the critical point of the confinement velocity is between L / H = 2 to L / H = 4 in section 1, between L / H = 1 to L / H = 2 in section 2, rather than a fixed value; Two tunnel models had similar dimensionless confinement velocity, but the dimensionless total confinement velocity was different.

scholarly journals Numerical 3D Simulation of a Longitudinal Ventilation System: Memorial Tunnel Case

2006 ◽  
Author(s):  
Monica Galdo-Vega ◽  
Rafael Ballesteros-Tajadura ◽  
Carlos Santolaria-Morros
Keyword(s):  
Numerical Models ◽  
Ventilation System ◽  
Fire Behavior ◽  
Full Scale ◽  
3D Simulation ◽  
Full Scale Test ◽  
Road Tunnel ◽  
Tunnel Fire ◽  
Longitudinal Ventilation ◽  
Scale Test

In this work, a numerical 3D simulation of a longitudinal ventilation system is developed to analyze the fire behavior inside a road tunnel. Recent disasters, like crashes in the Mont Blanc tunnel (France, 1999) or San Gottardo (Italy, 2001), have shown the need for better integral actions during possible fire incidents. The minimum delay time, required for starting the jet fans, or the evolution of the smoke patterns inside the tunnel are critical issues when rescue plans are designed. Some methods to study the smoke propagation during a fire are: pseudo-thermal scale models, full scale test and numerical models. Several contributions using the first method can be found in references [1], [2] and [3]. However it is very difficult to extrapolate the results from this kind of models. The second method (full scale test) is the most expensive of all and only two of them have been conducted recently: EUREKA Project [4] and the Memorial Tunnel Fire Ventilation Test Program [5]. The last method (numerical models) it is now under development. The objective of this work is to validate a numerical model, to predict the behavior of the smoke generated during a fire incident inside a road tunnel, comparing its results with previous experimental data collected in the Memorial Tunnel Project. In addition, a good agreement was achieved, so a methodology to predict the performance of a longitudinal ventilation system in case of fire was accurately established.

scholarly journals Study on Hot Gases Flow in Case of Fire in a Road Tunnel

2018 ◽  
Author(s):  
Aleksander Król ◽  
Małgorzata Król
Keyword(s):  
Temperature Distribution ◽  
Initial Phase ◽  
Ventilation System ◽  
Main Axis ◽  
Road Tunnel ◽  
Ansys Fluent ◽  
The Road ◽  
Longitudinal Ventilation ◽  
Australian Standard ◽  
Recorded Data

This paper presents the results of hot smoke tests, conducted in a real road tunnel. The tunnel is located within the expressway S69 in southern Poland between cities Żywiec and Zwardoń. Its common name is Laliki tunnel. It is a bi-directional non-urban tunnel. The length of the tunnel is 678 m and it is inclined by 4%. It is equipped with the longitudinal ventilation system. Two hot smoke tests have been carried out according to Australian Standard AS 4391-1999. Hot smoke tests corresponded to a HRR (Heat Release Rate) equal to respectively 750 kW and 1500 kW. The fire source was located in the middle of the road lane imitating an initial phase of a car fire (respectively 150 m and 265 m from S portal). The temperature distribution was recorded during both tests using a set of fourteen thermocouples mounted at two stand poles located at the main axis of the tunnel on windward. The stand poles were placed at distances of 5 m and 10 m. The recorded data were applied to validate of a numerical model built and solved using Ansys Fluent. The calculated temperature distribution matched the measured values.

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