Evolution characteristics of fire smoke layer thickness in a mechanical ventilation tunnel with multiple point extraction

2017 ◽  
Vol 111 ◽  
pp. 248-256 ◽  
Author(s):  
Fengzhu Mei ◽  
Fei Tang ◽  
Xiang Ling ◽  
Jinshan Yu
Keyword(s):  
Mechanical Ventilation ◽  
Layer Thickness ◽  
Multiple Point ◽  
Evolution Characteristics ◽  
Fire Smoke ◽  
Smoke Layer

On the Smoke Propagation of a Fire in a Tunnel With Concentrated Exhaust Ventilation

2011 ◽  
Author(s):  
Futoshi Tanaka ◽  
Masahiro Kato ◽  
Shouhei Majima ◽  
Nobuyoshi Kawabata ◽  
Tomoki Kikumoto ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Scaling Law ◽  
Experimental Results ◽  
Exhaust Ventilation ◽  
Tunnel Fire ◽  
The People ◽  
Fire Smoke ◽  
Smoke Layer ◽  
Fire Accidents ◽  
Real Scale

In recent years, tunnel fire accidents of about 20 occur every year in Japan. The Nihonzaka and the Sakai tunnel fire accidents are as famous typical examples. When concentrated exhaust ventilation device is activated in such a tunnel fire, it is of concern that the people who take shelter receive damage from the fire smoke. When a tunnel fire occurs, the concentrated exhaust ventilation device is stopped in Japan. Therefore, the research on the use of concentrated exhaust ventilation device at a tunnel fire has not advanced in Japan. The purpose of this study is to clarify the smoke propagation when concentrated exhaust ventilation device is activated. The model tunnel in the scale of 1/5 was used in this study. Froude scaling law was used to make the experimental results of the model tunnel correspond to the real scale tunnel. The concentrated exhaust ventilation device installed on the model tunnel extracts the fire smoke from a chimney. The smoke distribution in the model tunnel was measured with smoke concentration meters. In the case that the exhaust ventilation device was activated, the smoke layer thickness of the downstream of the chimney thinned. However, in the upstream of the chimney, the smoke layer thickness did not change though the exhaust ventilation device was activated.

Determinations of the fire smoke layer height in a naturally ventilated room

2013 ◽  
Vol 58 ◽  
pp. 1-14 ◽  
Author(s):  
Chi-ming Lai ◽  
Chien-Jung Chen ◽  
Ming-Ju Tsai ◽  
Meng-Han Tsai ◽  
Ta-Hui Lin
Keyword(s):  
Layer Height ◽  
Fire Smoke ◽  
Smoke Layer

Multi-Cell Concept for Simulating Fires in Big Enclosures Using a Zone Model

1996 ◽  
Vol 14 (3) ◽  
pp. 186-198 ◽  
Author(s):  
W.K. Chow
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Temperature Distribution ◽  
Physical Properties ◽  
Flow Pattern ◽  
Layer Thickness ◽  
Zone Model ◽  
Smoke Layer

The multi-cell concept is applied to simulate fire in a big com partment with the zone model CFAST. The predicted physical properties of the smoke layer are used to justify the results, including the smoke layer tempera ture, smoke layer thickness and flows between each cell. Microscopic pictures of the flow pattern and smoke temperature distribution similar to the results pre dicted by the Computational Fluid Dynamics technique can be obtained. This idea is recommended to study fires in big enclosures.

Heat transfer and smoke flow filling progress in a super-high atrium under influence of fire source characteristics

2019 ◽  
Vol 37 (3) ◽  
pp. 213-235
Author(s):  
Yanqiu Chen ◽  
Dong Wang ◽  
Junmin Chen
Keyword(s):  
Heat Transfer ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Smoke Flow ◽  
Fire Source ◽  
Fire Smoke ◽  
Smoke Layer ◽  
Pressure Area ◽  
Boltzmann Model

Heat transfer and smoke flow filling progress in a super-high atrium is studied in this article. The influences of heat release rate and fire source height were considered. It was found that the fire smoke layer could not reach the top of the atrium when the heat release rate was very low and the fire source was located at the bottom of the atrium. The temperature of smoke layer interface and Δ Tmax were linearly positively related to Q2/3, while Δ Pmax was quadratically positively related to Q2/3. At the top of the atrium, the temperature rise and fire source height were consistent with the Boltzmann model. As the fire smoke rose with a velocity, a relatively low-pressure area was generated below. The pressure variation in this area was negatively index-related to the fire source height.

scholarly journals An Estimation Method of Fire Extinguishing Time in Closed Ship Cabin

2020 ◽  
Vol 165 ◽  
pp. 06007
Author(s):  
Tang Fang ◽  
Li Pan ◽  
Chen Guofeng ◽  
Xie Jianghui
Keyword(s):  
Structural Characteristics ◽  
Estimation Method ◽  
Mass Conservation ◽  
Zone Model ◽  
Fire Hazards ◽  
Fire Extinguishing ◽  
Fire Smoke ◽  
Smoke Layer ◽  
Fire Scene ◽  
Closed Environment

There are many potential fire hazards in ship engine cabin, especially in the closed environment of submarine underwater. Fires in cramped cabin are usually harder to put out, therefore, enclosing cabin is a possible means of extinguishing fire. In this paper, typical fire scene in ship engine cabin is analyzed firstly, then a two-layer zone model of engine cabin fire is established combined with structural characteristics of engine cabin. According to the mass conservation and energy conservation, fire smoke layer change rule is described to estimate extinguishing time. At last, typical hydraulic jet fire and electrical fire smoke layer calculation is taken as an example. The result shows that enclosing cabin is a fast and effective method, and the method of estimating fire extinguishing time in engine cabin by this paper is feasible.

A Study on Tunnel Smoke Control Strategies by Experiment and Numerical Simulation

2011 ◽  
Vol 402 ◽  
pp. 864-867
Author(s):  
Xiao Yang Liu ◽  
Jing Yan Zhang ◽  
Yan Feng Li ◽  
Li Li Zhang ◽  
Jin Feng Yuan
Keyword(s):  
Scale Model ◽  
Road Tunnel ◽  
Smoke Control ◽  
Fire Control ◽  
Fire Dynamics ◽  
Tunnel Fire ◽  
Longitudinal Ventilation ◽  
Fire Smoke ◽  
Smoke Layer ◽  
Layer Velocity

In order to meet the need of the study on the tunnel fire safety system, taking the tunnel laboratory bench in the key laboratory of the university of science and technology of China as the object, this paper does a scale model experiment on the tunnel fire, and uses the Fire Dynamics Simulator（FDS）software to simulate fire smoke layer velocity under different longitudinal ventilation control, by comparing the experimental and simulation results, this paper not only gives the variation law of the tunnel fire smoke layer velocity under different longitudinal ventilation speed, but also proposes the concept of the smoke stratification critical wind speed , which will provide some references for the road tunnel fire control, rescue and evacuation.

Study on Design Optimization of Fire Smoke Control Modes for Subway Transfer Channel With Ceiling Beams

2020 ◽  
Author(s):  
Xiangliang Tian ◽  
Chang Liu ◽  
Maohua Zhong
Keyword(s):  
Great Influence ◽  
Exhaust System ◽  
Control Effect ◽  
Smoke Control ◽  
Emergency Rescue ◽  
Ceiling Temperature ◽  
Fire Smoke ◽  
Smoke Layer ◽  
Co Concentration ◽  
Transfer Channel

Abstract In order to study the optimization modes of smoke control in the case of fire in metro transfer channel, a full-scale numerical station model with a single transfer channel is established. In case of fire, the influencing of ceiling beam, vent size on smoke control effect are analyzed. The ceiling temperature profile, CO concentration, visibility and smoke layer height under different conditions were studied to evaluate the smoke control effect of transfer channel and station hall. Based on this, the optimization suggestions of ventilation and smoke exhaust system design and smoke control modes for transfer channel are put forward. The results show that, the ceiling beams can effectively delay the speed of smoke diffusion and gain time for personnel escape and emergency rescue. The vent size has a great influence on the ventilation and smoke exhaust effect under the condition of meeting the designed ventilation capacity. Among the three common vent sizes listed in this research, the smaller the size is, the better the smoke control effect is. The length and width of vent with best smoke control effect are 1.2 m and 0.8m respectively.

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