Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
4.9
2.7
Journals
Symmetry
Special Issues
Asymmetry in Fire Dynamics and Modelling
share announcement

Asymmetry in Fire Dynamics and Modelling

A special issue of Symmetry (ISSN 2073-8994). This special issue belongs to the section "Computer".

Deadline for manuscript submissions: closed (16 January 2023) | Viewed by 6152

Special Issue Editors

Dr. Xiaolei Zhang

E-Mail Website
Guest Editor
State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026, China
Interests: fire dynamics; buoyant flow dynamics; fire plume entrainment; combustion; flame spread behavior; heat transfer; fire modelling
Special Issues, Collections and Topics in MDPI journals
Dr. Wei Tang

E-Mail
Guest Editor
Pittsburgh Mining Research Division, National Institute for Occupational Safety and Health, Pittsburgh, PA 15236, USA
Interests: fire behavior; smoke transport; flame shape; fire plume; heat transfer; wind driven flow
Dr. Jianping Zhang

E-Mail Website
Guest Editor
Belfast School of Architecture and the Built Environment, Ulster University, Newtownabbey, Northern Ireland, BT37 0QB, UK
Interests: enclosure and façade fire dynamics; material flammability and fire testing; computational fluid dynamics (CFD) modelling of flames and fires; modelling of human behavior and evacuation; numerical analysis of heat transfer and pyrolysis of solids; quantitative risk analysis
Special Issues, Collections and Topics in MDPI journals
Dr. Qiang Wang

E-Mail Website1 Website2
Guest Editor
School of Automobile and Transportation Engineering, Hefei University of Technology, Hefei 230009, China
Interests: jet flame; flame instability; flame spread over solid fuel; blow out; lift off
Special Issues, Collections and Topics in MDPI journals
Dr. Xiaochun Zhang

E-Mail
Guest Editor
School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
Interests: compartment fire dynamics, ceiling jet flow, fire and pollutant transportation under wind, combustion characteristics of jet flame; emergency rescue drill system based on virtual reality
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Symmetry exists widely in nature. The most common phenomenon is the symmetry of morphology. Symmetry is also an important notion in physics and engineering. For instance, classical symmetric plume model which is derived from conservation laws, has been applied in many areas.

Enormous attention has been paid to fire safety due to the many disastrous accidents reported worldwide. The symmetry is also deeply related with fire dynamics. For a free burning fire from a circular source in still air, the plume characteristic parameters (shape, temperature profile, smoke concentration, etc.) are highly symmetrical. Based on the conservation laws and dimensional analysis, classical fire dynamics models have been established with the help of such symmetry. However, fire plume sometimes will be asymmetric due to the changing in boundary conditions, for example, the wall restriction or the ambient wind. The classical models are not applicable anymore for asymmetric fire plumes, and theoretical analyses based on conservation laws in asymmetrical fire plume are critical for the development of fire dynamics and modelling.

The scope of this Special Issue is to gather original fundamental and applied research concerning experimental, theoretical, computational and case studies that contribute towards the understanding of the asymmetry phenomena in fire dynamics and modelling. The topics include, but are not limited to:

  • morphologic characteristics of fire plume
  • distribution of characteristic parameters (temperature profile, smoke concentration, etc.)
  • fire modelling in computational fluid dynamics
  • pedestrian dynamics in fire evacuation
  • asymmetry air entrainment induced by the wall restriction
  • fire plume behavior under the effect of wind
  • burning behavior of multiple fires
  • case study of fire accident

Prof. Dr. Xiaolei Zhang
Dr. Wei Tang
Dr. Jianping Zhang
Prof. Dr. Qiang Wang
Dr. Xiaochun Zhang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Symmetry is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (3 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

25 pages, 37268 KiB  
Article
Numerical Study on Effects of Geometric Parameters on the Release Characteristics of Straight Sudden Expansion Gas Extinguishing Nozzles
by Quanwei Li, Xiaohua He, Yongbing Chen, Jiang Lin, Yi Zhang, Ruiyu Chen and Xia Zhou
Symmetry 2021, 13(12), 2440; https://doi.org/10.3390/sym13122440 - 17 Dec 2021
Cited by 2 | Viewed by 1867
Abstract
In order to guide the optimization design of the nozzle of the aircraft-fixed gas fire extinguishing system, we studied the influence of nozzle geometric parameters including outlet–inlet area ratio, length–diameter aspect ratio, and wall roughness on the distribution of pressure and velocity in [...] Read more.
In order to guide the optimization design of the nozzle of the aircraft-fixed gas fire extinguishing system, we studied the influence of nozzle geometric parameters including outlet–inlet area ratio, length–diameter aspect ratio, and wall roughness on the distribution of pressure and velocity in the nozzle on the basis of CFD simulations. Although the structure of the nozzle is axisymmetric, the spatial distribution of the pressure and velocity during the flow and release of gas extinguishing agent is not completely symmetric. It was found that both of the outlet–inlet area ratio (δ) and the length–diameter aspect ratio (ξ) had a significant impact on the distribution characteristics of the pressure and axial velocity in the nozzle. With the increase of δ, the average pressure at the outlet cross-section of the nozzle decreased monotonically, while the average axial velocity at the outlet increased approximately linearly. When ξ≥2, the uniformity of the pressure and velocity distribution at the nozzle outlet was significantly improved. Moreover, with the increase of ξ, the average pressure and the average axial velocity of the outlet both showed a non-monotonic change trend, and the optimal value of ξ should be about 3.0. Compared with δ and ξ, the influence of the nozzle wall roughness (εN) on the flow and release characteristics of the extinguishing agent was weak. With the increase of εN, the average pressure of the nozzle outlet increased slightly, while the average axial velocity at the nozzle outlet decreased slightly. Full article
(This article belongs to the Special Issue Asymmetry in Fire Dynamics and Modelling)
►▼ Show Figures

Figure 1

17 pages, 1329 KiB  
Article
Numerical Simulation of the Evacuation Process in a Tunnel during Contraflow Traffic Operations
by Razieh Khaksari, Zambri Harun, Les Fielding and John Aldridge
Symmetry 2021, 13(12), 2392; https://doi.org/10.3390/sym13122392 - 11 Dec 2021
Cited by 5 | Viewed by 2508
Abstract
The purpose of this numerical research is to assess the evacuation process in a tunnel under the contraflow condition. Numerical simulations utilizing FDS+Evac codes associated with a fire dynamic simulator (FDS) model simulating a fire scenario are used to simulate evacuation and to [...] Read more.
The purpose of this numerical research is to assess the evacuation process in a tunnel under the contraflow condition. Numerical simulations utilizing FDS+Evac codes associated with a fire dynamic simulator (FDS) model simulating a fire scenario are used to simulate evacuation and to predict the impact of a 100 MW fire scenario on the occupants inside the tunnel. Traffic and passenger conditions are based on real data from a tunnel in the UK. Two fire loads, 100 MW and 5 MW, are studied to represent an HGV and a passenger car fire. The 100 MW fire source, caused by an unexpected heavy good vehicle (HGV) catching fire, is located in the middle of the tunnel and at 20% of tunnel length to study the effect of fire source location on the usage of emergency exits and tenability thresholds. The dimensions and the inclination angle of the existing roadway tunnel are 1836 m (L) × 7.3 m (W) × 5 m (H) and 4%, respectively. It should be noted that the 4% inclination of the tunnel causes asymmetry propagation of smokes thus the visibility of the downstream and upstream from the fire behave differently. The maximum needed time to evacuate using all egress, the amount of fractional effective dose and visibility at the human’s height are analyzed. Simulation results indicate that when a realistic worst-case fire scenario is modeled, all evacuees can survive before the combustion gases and heat influence their survivability. Full article
(This article belongs to the Special Issue Asymmetry in Fire Dynamics and Modelling)
►▼ Show Figures

Figure 1

27 pages, 4984 KiB  
Article
Numerical Study on Effects of Pipeline Geometric Parameters on Release Characteristics of Gas Extinguishing Agent
by Quanwei Li, Zongyu Li, Ruiyu Chen, Zhaojun Zhang, Hui Ge, Xia Zhou and Renming Pan
Symmetry 2021, 13(10), 1766; https://doi.org/10.3390/sym13101766 - 23 Sep 2021
Cited by 3 | Viewed by 1530
Abstract
In order to guide the optimization design of the pipeline network of the aircraft-fixed gas fire extinguishing system and improve its fire extinguishing performance, FLUENT software was used to simulate the influence of pipeline parameters such as diameter, length, and roughness on the [...] Read more.
In order to guide the optimization design of the pipeline network of the aircraft-fixed gas fire extinguishing system and improve its fire extinguishing performance, FLUENT software was used to simulate the influence of pipeline parameters such as diameter, length, and roughness on the release characteristics of the fire extinguishing agent. It can be found that the extinguishing agent can be divided into liquid and vapor extinguishing agents in the fire extinguishing pipeline system during the release. The spatial distribution and proportion of the liquid and vapor extinguishing agents are asymmetric. Results show that the peak value of the pressure drop rate (dPmax) has a good quadratic function relationship with the pipeline diameter (D) and the functional relationship is dPmax=−22.224+2.782D+0.089D2, which means that the peak value increased significantly with the increase in the pipeline diameter. Moreover, when the pipeline diameter is 25 mm, the average pressure drop rate of the vessel is about 35.02 MPa/s, which is 5.97 times the value of the average pressure drop rate when the pipeline diameter is 10 mm. With the increase in the pipeline diameter, the release time decreases significantly, the mass flow rate increases obviously, while the gasification ratio decreases rapidly at first and then increases slightly. The pipeline length also has a significant influence on the release characteristics of the extinguishing agent. With the increase in the pipeline length, the release time and the gasification ratio increase linearly, while the mass flow rate decreases linearly. Compared with the pipeline diameter and pipeline length, the influence of the pipeline roughness on the release characteristics of the extinguishing agent is weak. With the increase in the pipeline roughness, the release time and the gasification ratio of the extinguishing agent increases slowly, while the mass flow rate decreases slowly. Full article
(This article belongs to the Special Issue Asymmetry in Fire Dynamics and Modelling)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-3
Back to TopTop