scholarly journals Impact of a Change from an Aluminium- to a Composite-Type Aircraft on Wind-Assisted Aviation-Fuel Fire Dynamics - a Numerical Study

2020 ◽  
Vol 4 (2) ◽  
Author(s):  
Wang HY ◽  
Wang GD
Keyword(s):  
Numerical Study ◽  
Aviation Fuel ◽  
Fire Dynamics ◽  
Composite Type

scholarly journals Numerical Study of Large-Scale Fire in Makkah’s King Abdulaziz Road Tunnel

Fluids ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 5
Author(s):  
Kamel Guedri ◽  
Abdullah A. Abdoon ◽  
Omar S. Bagabar ◽  
Mowffaq Oreijah ◽  
Abdessattar Bouzid ◽  
...  
Keyword(s):  
Large Scale ◽  
Unit Area ◽  
Numerical Study ◽  
Human Life ◽  
Gas Temperature ◽  
Road Tunnel ◽  
Air Velocity ◽  
Fire Dynamics ◽  
Tunnel Fires ◽  
Heat Released

Tunnel fires are one of the most dangerous catastrophic events that endanger human life. They cause damage to infrastructure because of the limited space in the tunnel, lack of escape facilities, and difficulty that intervention forces have in reaching the fire position, especially in highly crowded areas, such as Makkah in the Hajj season. Unfortunately, performing experimental tests on tunnel fire safety is particularly challenging because of the prohibitive cost, limited possibilities, and losses that these tests can cause. Therefore, large-scale modeling, using fire dynamic simulation, is one of the best techniques used to limit these costs and losses. In the present work, a fire scenario in the Makkah’s King Abdulaziz Road tunnel was analyzed using the Fire Dynamics Simulator (FDS). The effects of the heat released per unit area, soot yield, and CO yield on the gas temperature, radiation, concentrations of the oxygen and combustion products CO and CO2, and air velocity were examined. The results showed that the radiation increased with the heat released per unit area and the soot yield affected all parameters, except the oxygen concentration and air velocity. The CO yield significantly affects CO concentration, and its influence on the other studied parameters is negligible. Moreover, based on the validation part, the results proved that FDS have limitations in tunnel fires, which impact the smoke layer calculation at the upstream zone of the fire. Therefore, the users or researchers should carefully be concerned about these weaknesses when using FDS to simulate tunnel fires. Further comprehensive research is crucial, as tunnel fires have severe impacts on various aspects of people’s lives.

Numerical Study on the Outdoor Wind Effects on Movement Smoke along a Corridor

2020 ◽  
Author(s):  
Brady Manescau ◽  
Khaled Chetehouna ◽  
Quentin Serra ◽  
Aijuan Wang ◽  
Eric Florentin
Keyword(s):  
Fluid Dynamics ◽  
Input Data ◽  
Numerical Study ◽  
Numerical Data ◽  
Experimental Result ◽  
Fire Dynamics ◽  
Entire Volume ◽  
Global Sensitivity ◽  
Fire Dynamics Simulator ◽  
Computational Fluid Dynamics Cfd

In this chapter, a numerical investigation is presented in order to highlight the effects of outdoor wind on smoke movements along a corridor in a compartment. For this, the Computational Fluid Dynamics (CFD) code, fire dynamics simulator (FDS), was used to model the reactive flows in interaction with outdoor wind. The wind velocity is taken between 0 and 12.12 m/s, based on the experimental result data come from the work of Li et al. was performed. From numerical data, it was found that smoke stratification state in the corridor depends on Froude number (Fr) and it can be divided into three cases: stable buoyant stratification (Fr < 0.38), unstable buoyant stratification (0.38 ≤ Fr < 0.76), and failed stratification (Fr ≥ 0.76). When Fr ≥ 0.76, smoke stratification is completely disturbed and smoke occupies the entire volume of the compartment, highlighting a risk of toxicity to people. Indeed, it was observed that the velocity of the outdoor wind influences strongly the concentration of O2, CO2, CO, and visibility in the corridor and smoke exhaust. Moreover, for the input data used in the numerical modelling, the global sensitivity analysis demonstrated that the main parameters affecting the smoke temperature near the ceiling are the mass flux of fuel and the activation energy.

scholarly journals Numerical Study on the Attenuation Effect of Water Mist on Thermal Radiation

2020 ◽  
Vol 34 (4) ◽  
pp. 7-12
Author(s):  
Gwon Hyun Ko
Keyword(s):  
Thermal Radiation ◽  
Droplet Size ◽  
Numerical Study ◽  
Water Mist ◽  
Spray Angle ◽  
Fire Dynamics ◽  
Radiation Attenuation ◽  
Attenuation Effect ◽  
Spray Droplets ◽  
Hot Surface

A numerical study was conducted to investigate the effects of the spray characteristics of water mist on the attenuation of thermal radiation. The attenuation process of the thermal radiation, generated from a hot surface panel, passing through the water mist was calculated via Fire Dynamics Simulator (FDS), and the effects of the flow rate, droplet mean diameter, and spray injecting angle of the water mist were analyzed. The results indicated that the increase in flowrate and decrease in droplet size led to an increase in the attenuation of thermal radiation. As the thermal radiation passed through the spray droplets, the effect of the spatial distribution of spray droplets was verified by calculating the thermal radiation attenuation at different spray injecting angles. The results indicated that the radiation attenuation increases as the spray angle increases. This implies that a wider distribution of spray droplets, irrespective of the droplet size and flowrate, increases the attenuation effect on thermal radiation.

Numerical Study of Solid Biomass Fuel in a Gasifier System

2014 ◽  
Vol 953-954 ◽  
pp. 191-194
Author(s):  
Ming Yung Wang ◽  
Hsiao Kang Ma
Keyword(s):  
Numerical Study ◽  
Fixed Bed ◽  
Biomass Fuel ◽  
Waste Biomass ◽  
Operation Condition ◽  
Fire Dynamics ◽  
Fuel Gas ◽  
Cold Gas Efficiency ◽  
Downdraft Fixed Bed ◽  
Solid Biomass

In this study, the gasification processes of different Taiwan’s agriculture wastes were studied by using software of Fire Dynamics Simulator (FDS), which developed by American National Institute of Standards and Technology (NIST), to build a model of downdraft fixed bed gasifier. Details of the operation condition for the Taiwan’s agriculture waste biomass fuel in the gasifier were obtained. They include traction fan speed, leakage air, internal temperature, moisture, and cold gas efficiency. The simulated results are found in small type fixed bed biomass gasifier under traction fan initial speed is 0.2m/s, the leakage air in the gasification area is less than 10% of the amount of wind quantity by traction fan and moisture content of solid biomass is limited at 10% ~ 20%(vol.) that temperature in gasification zone with steady supply fuel gas condition is near 850~900°C.

scholarly journals Numerical study on the effect of shaft position on natural smoke exhaust in tunnels with one closed portal

2020 ◽  
Vol 194 ◽  
pp. 05061
Author(s):  
GENG Pengqiang ◽  
WANG Zihao ◽  
WENG Miaocheng ◽  
LIU Fang
Keyword(s):  
Temperature Distribution ◽  
Heat Release ◽  
Release Rate ◽  
Numerical Study ◽  
Fire Dynamics ◽  
Fire Dynamics Simulator ◽  
Fire Source ◽  
Tunnel Fire ◽  
Ceiling Temperature ◽  
Longitudinal Distance

.This paper uses Fire Dynamics Simulator (FDS) to study the effect of the longitudinal distance from the shaft to the fire source on the natural smoke exhaust of the tunnel fire with one closed portal, and analyzes the temperature distribution of the smoke and the shaft’s smoke exhaust efficiency. The results show that when the shaft is located downstream of the fire source (Ds<0), with the increase of the distance from the shaft to the fire source, the smoke exhaust efficiency decreases first and then stabilizes at a fixed value. At this time, the ceiling temperature attenuation’s coefficient at upstream of the fire source is only related to the heat release rate of the fire source (HRR). When the shaft is located upstream of the fire source (Ds>0), the smoke exhaust efficiency increases slightly with the increase of the distance from the shaft to the fire source, but the overall value is relatively small. When HRR is fixed, the shaft located downstream of the fire source has a higher smoke exhaust efficiency. As the distance between the shaft and the fire source increases, the plug phenomenon decreases.

scholarly journals High-Temperature Properties of a Long-Span Double-Deck Suspension Bridge under a Tanker Fire

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Mengsheng Yu ◽  
Qifeng Chen ◽  
Xinyu Yao ◽  
Xiao Guo ◽  
Tianzhi Hao ◽  
...  
Keyword(s):  
High Temperature ◽  
Failure Time ◽  
Numerical Study ◽  
Three Dimensional ◽  
Suspension Bridge ◽  
Element Model ◽  
Steel Plates ◽  
Fire Dynamics ◽  
Long Span ◽  
Upper Deck

This paper presents a numerical study on the high-temperature mechanical properties of a long-span double-deck suspension bridge. The main focus of this paper is the behavior analysis of Wuhan Yangtze River Bridge. A three-dimensional thermal model of the bridge was established by the Fire Dynamics software (FDS) to obtain the 3D temperature field distribution, and the thermal analysis result was then applied to the three-dimensional finite element model of the suspension bridge. The shortest failure time of the main cable and sling was determined to obtain the rescue time of a bridge fire. According to the calculation results of the suspension bridge under a tanker fire initiated at the upper deck of the bridge, the middle lane in the upper deck of the suspension bridge was determined to be a safe lane. Thus, the tanker should be guided to go in this lane of the bridge. The numerical analysis of the experimental results shows that when the fuel tanker is located on the upper and lower floors of the bridge, the bridge structure is affected by the fire. When the oil tanker burns in the outermost lane of the upper bridge, it will have a great impact on the main cables and slings of the bridge. When the fuel tanker burns in the lower nonmotorized lane of the bridge, it will have a great impact on the upper stiffening beam steel plates and truss rods.

Effect of different air settings over fire-induced condition in a stairwell

2017 ◽  
Vol 8 (4) ◽  
pp. 440-458
Author(s):  
Aristides Lopes da Silva ◽  
Shengwu Xiong ◽  
Hussain Aamir
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Design Methodology ◽  
Numerical Study ◽  
Air Velocity ◽  
Fire Dynamics ◽  
Content Type ◽  
Fire Dynamics Simulator ◽  
Air Inlet ◽  
Transient Measurements

Purpose This work aims to report the effect of different inlet air velocity settings, and the position of the inlet areas under fire-induced conditions in stairwells. Design/methodology/approach The results are evaluated both experimentally and numerically. In sequence, the study also describes the results of three tests under different ventilation conditions, which were performed by simulating a fire of 0.9 m diameter in a stairwell access door. Detailed transient measurements of air temperature in the walls, air velocity settings at the ventilation outlet, smoke temperature through the fans and pressure through the exhaust fans were recorded for the study. Findings These data could be used as benchmark for future numerical validation studies. Based on computational fluid dynamics, the tests were performed using fire dynamics simulator codes, to compare the results of tests and simulations. Originality/value The numerical study was performed in confined floors close to the test areas of a typical stairwell, with different vents and a source of fire. The results show that the lack of symmetry in the air vents settings has greater influence on the plume than the total area of the air inlet.

scholarly journals Field modeling of the fire dynamics as an answer to the question about the fire alarm performance

2020 ◽  
Vol 29 (5) ◽  
pp. 40-50
Author(s):  
I. R. Khasanov ◽  
A. V. Karpov ◽  
S. F. Lobova ◽  
N. V. Petrova
Keyword(s):  
Numerical Study ◽  
Combustion Model ◽  
Smoke Detector ◽  
Fire Load ◽  
Fire Dynamics ◽  
Fire Alarm ◽  
Combustion Models ◽  
Field Modeling ◽  
Smoke Detectors ◽  
The Impact

Introduction. The performance of a fire alarm needs to be analyzed to answer the question about its compliance with fire safety requirements. This type of research is frequently performed in the course of a forensic fire investigation. Therefore, it is necessary to identify conditions of fire escalation and safe evacuation of people to assess the fire alarm performance.Purposes and objectives. The purpose of this work is the numerical study of the impact, produced by mathematical models of combustion, characteristics of fire loads and locations of fire beds, on fire alarm performance. Methods. Fire dynamics was field modeled to achieve the goal of this research. The analysis of flame propagation was performed with regard for various fire bed locations to simulate the fire alarm operation.Results and discussion. The fulfillment of safe evacuation conditions for cases of irregular arrangement of smoke detectors was analyzed to develop and test the algorithm for the calculation of the evacuation start time. It is shown that the estimated time of fire detection depends on combustion models employed (their average or complex level), the size of the computational grid, fire load specifications and the location of the fire bed.Conclusions. It is shown that the results of the field modeling of fire propagation and detection time are influenced by combustion models used, fire load specifications and the location of the fire bed in relation to smoke detectors. If the fire alarm fails to perform its functions and, consequently, safe evacuation conditions are not fulfilled, it is necessary either to improve the combustion model or to compare the modeling results obtained for actual and standard smoke detector location patterns.

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