A method for design of smoke control of urban traffic link tunnel (UTLT) using longitudinal ventilation

Once the tunnel fires happened, it will cause a major accident. And the smoke control of the runnel is important to fire prevention. A numerical simulation of the fire smoke flow in the tunnel model is presented by using FDS. The influence of different longitudinal ventilation on fire smoke flow of tunnel is obtained. And providing theory basis for tunnel ventilation system design, smoke spread control and safety evacuation. The results shown that in order to avoid reverse-flow and extend the time of smoke at the top of tunnel, the longitudinal speed should be controlled in 3.4 m/s; because of the role of longitudinal ventilation, smoke flow resistance and longitudinal ventilation generated by the effect of smoke flow resistance make the gas temperature first rise and then down.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.3665 ◽

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.

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Network Flow Modelling for Optimizing Fire Smoke Control in Complex Urban Traffic Link Tunnels: Incorporating Heat Loss and Gas Species Generation Rate Calculation into Models

The Proceedings of 11th Asia-Oceania Symposium on Fire Science and Technology ◽

10.1007/978-981-32-9139-3_72 ◽

2019 ◽

pp. 993-1007

Author(s):

Dong Yang ◽

Yingli Liu ◽

Tao Du

Keyword(s):

Heat Loss ◽

Network Flow ◽

Urban Traffic ◽

Generation Rate ◽

Smoke Control ◽

Flow Modelling ◽

Fire Smoke ◽

Rate Calculation

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Effect Analysis of Different Exhaust Velocity on Fire Smoke Control in Subway Tunnel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.424-425.1224 ◽

2012 ◽

Vol 424-425 ◽

pp. 1224-1227

Author(s):

Xin Han ◽

Xiao Ming Gao ◽

Bei Hua Cong

Keyword(s):

Cfd Simulation ◽

Simulation Analysis ◽

Simulation Method ◽

Subway Tunnel ◽

Control Effect ◽

Smoke Control ◽

Effect Analysis ◽

Longitudinal Ventilation ◽

Fire Smoke ◽

Ventilation Velocity

Taking a subway tunnel as the research object and based on the CFD simulation method, this paper adopts a large eddy simulation analysis software FDS to simulate and analyze the effect of exhaust velocity on fire smoke control under the condition of the same longitudinal ventilation velocity in subway tunnel. The simulated results can provide some reference to design institutes in the selection of exhaust fan. While the longitudinal ventilation velocity set as 1m/s, the simulation results demonstrate that a quite good smoke control effect could be achieved when the exhaust velocity reaches 5 m/s in the smoke exhaust duct

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A Study on the Technique for Fire Smoke Control in Urban Traffic Link Tunnel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.638-640.1117 ◽

2014 ◽

Vol 638-640 ◽

pp. 1117-1127

Author(s):

Jie Zhu ◽

Jian Bo Wu ◽

Zhi Gang Zhang ◽

Xiao Ju Li

Keyword(s):

Similarity Theory ◽

Theoretical Calculations ◽

Fire Hazard ◽

Central Business District ◽

Extraction Methods ◽

Urban Traffic ◽

Control Technique ◽

Smoke Control ◽

Smoke Movement ◽

Fire Dynamics

Urban traffic link tunnels (UTLT) have a complex design and are a significant fire hazard. Due to the circular nature of the tunnels, smoke can easily spread through the tunnel during a fire and form a circulation loop, severely hampering safe evacuation and rescue. In this paper, the 2.8km long UTLT in Sichuan, China's Dayuan central business district (CBD) was the study subject. Fire dynamics and similarity theory were employed to perform theoretical calculations and numerical simulations targeting four different mechanical smoke extraction methods under typical fire conditions. Smoke movement was quantitatively analyzed, thus determining which of the four plans was the optimal smoke control technique: semi-transverse ventilation combined with sinking-courtyard air compensation, with ventilation beginning in the fire zone and the two flanking smoke control zones at a rate of 20 ventilations/hour. Our result provides a theoretical basis for designing and running a smoke control system in relevant projects at home and abroad, and serves as both a theoretical and a constructive practical ground for formulating regulations related to UTLT.

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