scholarly journals Study on Fire Smoke Distribution and Smoke Control in Extra-long Double-hole Tunnel

2020 ◽  
Vol 3 (4) ◽  
pp. p17
Author(s):  
Jingdan Gan ◽  
Feng Shan Wu ◽  
Hong Liu
Keyword(s):  
Simulation Software ◽  
Smoke Control ◽  
Air Curtain ◽  
Tree Analysis ◽  
Fire Smoke ◽  
Operation Period ◽  
The Cross ◽  
Accident Tree

Abstract： Construction of tunnels, as one of the main methods to solve physical traffic barriers, However, It vulnerable to the threat of fire during the process of tunnel operation period. In response to such situation, this article explores the smoke distribution of extra-long double-tube tunnel and its impact on evacuation in the event of a fire. This paper take the Jieling tunnel as an example, and applies Accident Tree Analysis (ATA) method combined with Fires Dynamics Simulator (FDS）simulation software to study the changes of harmful factors such as tunnel smoke. According to the research, when a fire occurs in an extra-long double-tube tunnel, It is concluded that people are supposed to be guided to leave via the nearest cross-passages as soon as possible, In the end analysis the roles that air curtains could play in the control of smoke. It is recommended to open the air curtain so that in such condition people away from the cross-passages have enough time to escape.

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.

Study on Fire Smoke Movement of Urban Traffic Link Tunnel

2014 ◽  
Vol 580-583 ◽  
pp. 1037-1041 ◽  
Author(s):  
Xiao Lin Yao ◽  
Zhi Gang Zhang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Simulation Software ◽  
Urban Traffic ◽  
Control Measures ◽  
Smoke Control ◽  
Smoke Movement ◽  
Exhaust Port ◽  
Fire Smoke ◽  
Fire Scenarios

Fire simulation software (FDS) was employed to simulate the fire smoke movement of urban traffic link tunnel (UTLT) under the semi-transverse ventilation. Numerical simulation and theoretical analysis were used to analyze the fire smoke movement in three fire scenarios. The analytical results show that: semi-transverse ventilation can effectively control the spread of fire smoke. When the exhaust air rate is certain, the exhaust port interval of 20 m and 50 m has little effect on function of smoke control. The research results provide references for the design of smoke control measures in UTLT.

scholarly journals Alignment determination of the Hayabusa2 laser altimeter (LIDAR)

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Hirotomo Noda ◽  
Hiroki Senshu ◽  
Koji Matsumoto ◽  
Noriyuki Namiki ◽  
Takahide Mizuno ◽  
...  
Keyword(s):  
Altimeter Data ◽  
Gravity Assist ◽  
Laser Altimeter ◽  
Trajectory Error ◽  
Flight Data ◽  
Camera Image ◽  
Operation Period ◽  
The Cross ◽  
Along Track

AbstractIn this study, we determined the alignment of the laser altimeter aboard Hayabusa2 with respect to the spacecraft using in-flight data. Since the laser altimeter data were used to estimate the trajectory of the Hayabusa2 spacecraft, the pointing direction of the altimeter needed to be accurately determined. The boresight direction of the receiving telescope was estimated by comparing elevations of the laser altimeter data and camera images, and was confirmed by identifying prominent terrains of other datasets. The estimated boresight direction obtained by the laser link experiment in the winter of 2015, during the Earth’s gravity assist operation period, differed from the direction estimated in this study, which fell on another part of the candidate direction; this was not selected in a previous study. Assuming that the uncertainty of alignment determination of the laser altimeter boresight was 4.6 pixels in the camera image, the trajectory error of the spacecraft in the cross- and/or along-track directions was determined to be 0.4, 2.1, or 8.6 m for altitudes of 1, 5, or 20 km, respectively.

Experimental study on fire smoke control using water mist curtain in channel

2018 ◽  
Vol 342 ◽  
pp. 231-241 ◽  
Author(s):  
Zhigang Wang ◽  
Xishi Wang ◽  
Yanqing Huang ◽  
Changfa Tao ◽  
Heping Zhang
Keyword(s):  
Experimental Study ◽  
Water Mist ◽  
Smoke Control ◽  
Fire Smoke

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.

Thermoelectric Generators of Sequentially Deposited Si/Si+Ge Nano-layered Superlattices

2009 ◽  
Vol 1181 ◽  
Author(s):  
Cydale Smith ◽  
Marcus Pugh ◽  
Hervie Martin ◽  
Rufus Durel Hill ◽  
Brittany James ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Beam ◽  
Absolute Temperature ◽  
Simulation Software ◽  
The Cross

AbstractEffective thermoelectric materials have a low thermal conductivity and a high electrical conductivity. The performance of the thermoelectric materials and devices is shown by a dimensionless figure of merit, ZT = S2sσ/ KTC, σ is the electrical conductivity T/KTC, where S is the Seebeck coefficient, T is the absolute temperature and KTC is the thermal conductivity. In this study we have prepared the thermoelectric generator device of Si/Si+Ge multi-layer superlattice films using the ion beam assisted deposition (IBAD). To determine the stoichiometry of the elements of Si and Ge in the grown multilayer films and the thickness of the grown multi-layer films Rutherford Backscattering Spectrometry (RBS) and RUMP simulation software package were used. The 5 MeV Si ion bombardments were performed to make quantum clusters in the multi-layer superlattice thin films to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and cross plane electrical conductivity.Keywords: Ion bombardment, thermoelectric properties, multi-nanolayers, Figure of merit.

Study of Fire Smoke Flow of Tunnel at Different Longitudinal Ventilation

2012 ◽  
Vol 226-228 ◽  
pp. 1472-1475
Author(s):  
Pei Pei Yang ◽  
Xiao Lu Shi ◽  
Bi Ming Shi
Keyword(s):  
Flow Resistance ◽  
Reverse Flow ◽  
Ventilation System ◽  
Gas Temperature ◽  
Smoke Control ◽  
Smoke Flow ◽  
Longitudinal Ventilation ◽  
Smoke Spread ◽  
Fire Smoke ◽  
Safety Evacuation

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.

Comparative Study on Stair verses Elevator Shaft Pressurization for Fire Smoke Control

2011 ◽  
Vol 11 (5) ◽  
pp. 17-23
Author(s):  
Kyung-Hwan Park ◽  
Soo-Hyun So ◽  
Myung-Oh Yoon
Keyword(s):  
Comparative Study ◽  
Smoke Control ◽  
Fire Smoke

Fire Smoke Simulation Analysis of the Flow Characteristics in Huge Building

2011 ◽  
Vol 368-373 ◽  
pp. 1182-1185
Author(s):  
Chan Juan Xu ◽  
Shu Ping Zhang ◽  
Jing Jing Zhang
Keyword(s):  
Simulation Analysis ◽  
Fire Hazard ◽  
Hazard Analysis ◽  
Flow Characteristics ◽  
Simulation Software ◽  
Smoke Flow ◽  
Fire Scenario ◽  
Fire Smoke ◽  
Convention Center ◽  
Sharing Space

To a large comprehensive convention center as an example, this paper analyses the flow characteristics of fire smoke of the main hall and the feasibility for sharing space as "Quasi safety zone". First, the fire scenario was identified through the fire hazard analysis, then, set a model and take a simulation analysis by fire simulation software FDS, based on this fire scenario which have been established. At last, draw conclusions according to the smoke flow properties.

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