Experimental and numerical simulation on smoke control effect and key parameters of Push-pull air curtain in tunnel fire

2022 ◽  
Vol 121 ◽  
pp. 104323
Author(s):  
Jingwei Ji ◽  
Wen Lu ◽  
Fuqing Li ◽  
Xiaoting Cui
Keyword(s):  
Numerical Simulation ◽  
Control Effect ◽  
Smoke Control ◽  
Air Curtain ◽  
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 Study on the Effect of Jet Direction of Compound Air Curtain on Smoke Control

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6983
Author(s):  
Zhiyong Zhou ◽  
Yao Lu ◽  
Yimeng Cui
Keyword(s):  
Working Conditions ◽  
Working Condition ◽  
Simulation Software ◽  
Control Effect ◽  
Smoke Control ◽  
Ansys Fluent ◽  
Air Curtain ◽  
Fire Source ◽  
Smoke Prevention ◽  
Fire Scene

High temperature smoke caused by fire is a major cause of casualties. In order to ensure the safety of personnel, it is very important to control the spread of smoke and enable personnel to quickly withdraw from the fire scene. While traditional hard isolation, such as fire doors, may hinder the safe evacuation of people, the use of an air curtain as a flexible isolation has received more and more attention from researchers. In this paper, the influence of jet direction of compound air curtain on the smoke control effect was studied, and six working conditions were designed. The temperature and smoke isolation of the compound air curtain were numerically simulated by using ANSYS FLUENT software. The parameters such as temperature, velocity pressure and velocity streamline were analyzed, and the smoke control effects of six different jet directions were discussed. The simulation results were verified by Pyrosim fire simulation software simulation software. The results show that the direction of jet flow has a significant influence on the smoke control effect, and the fire smoke control effect under working conditions 4 and 5 is better. The working condition 5 (both air curtain A and air curtain B have outward jet direction) has the best smoke prevention effect, which is suitable for a situation that is close to the fire source. Working condition 4 (outward direction of air curtain A and inward direction of air curtain B) has the second-best effect of smoke prevention, which is suitable for situations far from the fire source.

Numerical Simulation on the Influence of Double-Jet Air Curtain of Smoke-Preventing in Tunnel Fires

2013 ◽  
Vol 805-806 ◽  
pp. 1534-1537 ◽  
Author(s):  
Yuan Lv ◽  
Bin Cao ◽  
Li Jing Zhang ◽  
Gang Tao
Keyword(s):  
Numerical Simulation ◽  
Smoke Control ◽  
Air Curtain ◽  
Tunnel Fires ◽  
Control Capability ◽  
Dynamics Characteristic ◽  
Nozzle Spacing

Select a tunnel in Nanjing as a modeling object and simulate the smoke control capability of the air curtain when nozzle spacing changes.By analysis, the dynamics characteristic with the wider spacing parameters of air curtain nozzle is superior to the narrower one under the same condition.The top of the spacing of the air curtain nozzle is recommended to be 2 to 3 times the width of a single nozzle.

Study on the smoke propagation characteristics of metro tunnel fire under the effects of piston wind

2021 ◽  
pp. 1420326X2199842
Author(s):  
Fei Wang ◽  
Fang Liu ◽  
Imad Obadi ◽  
Miaocheng Weng
Keyword(s):  
Wind Speed ◽  
Bernoulli Equation ◽  
Propagation Characteristics ◽  
Control Effect ◽  
Smoke Control ◽  
Tunnel Fire ◽  
Longitudinal Ventilation ◽  
Smoke Spread ◽  
Fire Smoke ◽  
Metro Tunnel

Metro trains running in tunnels cause piston wind, and when a metro train stops in a tunnel due to a fire, the effect of the piston wind on smoke propagation characteristics cannot be ignored. In this paper, a theoretical model based on the unsteady flow theory of the Bernoulli equation was established to describe the change in piston wind speed under fire conditions. The characteristics of the smoke propagation in tunnel fires under the effect of the piston wind were analysed by means of numerical simulation. The result indicates that the piston wind has a significant effect on the characteristics of smoke distribution. In a longitudinally ventilated tunnel, whether the direction of piston wind is the same as that of longitudinal ventilation could seriously affect the control of fire smoke. When the direction is the same, the piston wind could enhance the smoke control effect of the longitudinal ventilation. Otherwise, the smoke control effect could be significantly diminished, and the smoke control by the critical wind speed of longitudinal ventilation would fail. The findings could contribute to a better understanding of the characteristics of tunnel fire to control smoke spread under the influence of piston wind.

Numerical Analysis of Evacuation from Taiwan Hsuehshan Tunnel Fire

2014 ◽  
Vol 955-959 ◽  
pp. 1840-1849
Author(s):  
Cherng Shing Lin ◽  
Kuo Da Chou
Keyword(s):  
Numerical Simulation ◽  
Fire Protection ◽  
Quantitative Data ◽  
Relevant Information ◽  
Simulation Software ◽  
Escape Time ◽  
Fire Dynamics ◽  
Fire Dynamics Simulator ◽  
Tunnel Fire ◽  
Protection Engineering

Taiwan is an island nation with numerous mountains and few plains. Consequently, the number of tunnel projects has gradually increased and tunnels are becoming longer. Because the number of large tunnels that exceed 1000 meters in length has increased, the effective escape and evacuation of people during a fire and the minimization of injury are crucial to fire protection engineers. For this study, an actual example of a fire that occurred in Hsuehshan Tunnel (12.9 kilometers and the longest tunnel in Southeast Asia) was used. A fire dynamics simulator (FDS) including numerical simulation software was applied to analyze this fire and the relevant information that was collected was compared and verified. The fire site simulation showed the escape and evacuation of people during the fire. Simulations of the original fire site and the possible escape time for people with various attributes were discussed to provide quantitative data and recommendations based on the analysis results, which can serve as a reference for fire protection engineering.

scholarly journals CFD-Based Determination of the Optimal Blowing and Suction Air Volume Ratio of Dual-Radial Swirl Shielding Ventilation in a Fully Mechanized Excavation Face

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Kuan Wu ◽  
Shiliang Shi ◽  
Yijie Shi ◽  
Yong Chen
Keyword(s):  
Ventilation System ◽  
Volume Ratio ◽  
Simulation Method ◽  
Dust Concentration ◽  
Dust Control ◽  
Underground Mines ◽  
Physical And Mental Health ◽  
Control Effect ◽  
Air Curtain ◽  
Air Volume

Dust is one of the main pollutants in coal mines, which seriously affects the physical and mental health of workers, as well as the safe production in underground mines. Dual-radial swirl shielding ventilation is a new ventilation method for a fully mechanized excavation face and can effectively reduce the dust concentration in the underground. The dust control effect of dual-radial swirl shielding ventilation is mainly affected by the thickness and integrity of the shielding air curtain, as well as the disturbance of the flow field near the air curtain. By changing the blowing and suction air volume ratio of the air duct, the strength of the radial air curtain can be improved, and the dust control effect of the dual-radial swirl shielding ventilation system can be effectively improved. In order to determine the optimal operating parameters of the dual-radial swirl shielding ventilation system, a numerical simulation method was used to conduct an in-depth study on the blowing and suction air volume ratio of the system. The results showed that when the blowing and suction air volume ratio of the air duct was 1.5, the radial air curtain had the highest strength. Under this condition, the dust concentration at the driver’s position of the roadheader was the lowest, and the dual-radial swirl shielding ventilation system can achieve an ideal dust control effect.

Numerical Simulation Analysis of Smoke Control and Flow for Large Building Fire

2014 ◽  
Vol 608-609 ◽  
pp. 61-65
Author(s):  
Da You ◽  
Xiao Zhi Wang ◽  
Wen Jiang Chen ◽  
Gui Xiang Wu
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
Simulation Software ◽  
Double Precision ◽  
Actual Situation ◽  
Smoke Control ◽  
Fire Temperature ◽  
Building Fire ◽  
Engineering Software ◽  
Large Building

In fluid numerical simulation calculation, FLUENT is one of the most commonly used engineering software. By the way of pressure velocity coupling, FLUENT can solve the flow field, and use the finite volume method to speed up the convergence. In order to improve the calculation accuracy, FLUENT is divided into single precision and double precision to meet the need of practical engineering. In this paper, by using FLUENT numerical simulation software, combined with UDF programming, we analyze the temperature and smoke distribution when large building fire occurs. The GAMBIT software is used for the numerical modeling, and we use Tecplot software to carry out the post processing of results. Through numerical simulation, the fire temperature value reaches 1050K without wind, while with wind the temperature is 1030K, , which is consistent with the actual situation. In the absence of ventilation condition, concentration is 0.0112; under the condition of ventilation concentration is 0.0052, which is consistent with the actual situation. Therefore in the building fire safety, the first thing to consider is ventilation, which can reduce the fire temperature and concentration and security personnel safe evacuation.

Numerical Simulation Study on Air-Flow Migration Law about Vortex Air Curtain of Plane Wall Fan Drum

2012 ◽  
Vol 241-244 ◽  
pp. 1285-1292
Author(s):  
Gang Zhou ◽  
Sen Cao ◽  
De Ming Wang ◽  
Wei Min Cheng ◽  
Wen Nie
Keyword(s):  
Numerical Simulation ◽  
Control System ◽  
Simple Algorithm ◽  
Plane Wall ◽  
Dust Control ◽  
High Concentration ◽  
Air Curtain ◽  
Working Face ◽  
Simulation Results ◽  
Migration Law

Vortex air curtain of plane wall fan drum can control the diffusion of air stripping dust effectively. In order to solve the high-concentration dust problem in fully mechanized excavation face, formation mechanism of vortex air curtain was analyzed. According to fluid mechanical control equations of gas phase flow, mathematical model was established to solve air migration law of vortex air curtain in fully mechanized excavation face. By using Simple algorithm based on collocated grid and fluent software, numerical simulation of air spatial migration law of closed-end dust control in fully mechanized excavation face was carried out. The simulation results show that vortex air curtain dust control system can form dust control fan drum along driving head to the front of the roadheader driver. According to the simulation results and actual conditions of working face field, vortex air curtain suction dust control system consisted of plane wall fan drum and exhausted dust purification device in fully mechanized excavation face was designed, and after it was applied in fully mechanized excavation face, the dust concentration decreased effectively in the working face field.

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