Effect of fuel concentration, inert gas dilutions, inert gas–water mist twin fluid medium dilutions, and end boundary condition on overpressure transients of premixed fuel vapor explosion

Fuel ◽  
2022 ◽  
Vol 309 ◽  
pp. 122083
Author(s):  
Shimao Wang ◽  
Yunxiong Cai ◽  
Hai Guo ◽  
Dejian Wu ◽  
Yongliang Xie
Keyword(s):  
Boundary Condition ◽  
Water Mist ◽  
Inert Gas ◽  
Fuel Vapor ◽  
Vapor Explosion ◽  
Fluid Medium ◽  
Fuel Concentration

Characterization of Twin-Fluid (Water Mist and Inert Gas) Fire Extinguishing Systems by Testing and Modeling

2014 ◽  
Vol 51 (4) ◽  
pp. 923-950 ◽  
Author(s):  
Hong-Zeng Yu ◽  
Robert Kasiski ◽  
Matthew Daelhousen
Keyword(s):  
Water Mist ◽  
Inert Gas ◽  
Fire Extinguishing

Evaluation of propane explosion with applied water mist

2021 ◽  
Vol 39 (6) ◽  
pp. 443-454
Author(s):  
Ping-Jung Li ◽  
Chao-Shi Chen ◽  
Cheng-Yu Weng ◽  
Hsin-Hsiu Ho
Keyword(s):  
Water Mist ◽  
Experimental Results ◽  
Gas Explosion ◽  
Applied Water ◽  
Occurrence Time ◽  
Fuel Concentration ◽  
Explosion Suppression ◽  
Explosion Limit ◽  
Air Speed ◽  
Entrained Air

This article discusses the overpressure of a gas explosion and the performance of applying water mist for explosion suppression. According to the experimental results, the larger the opening area, the more difficult it is for pressure to accumulate, resulting in lower overpressure of a gas explosion. When the opening was opened under a high air speed environment, the amount of entrained air was greater. Consequently, the occurrence time of the explosion was shorter than at a low air speed. Despite the water mist nozzle being installed outside the enclosure, a propane gas explosion still occurred regardless of the amount of water mist used, failing to suppress the explosion. However, the water mist nozzle installed inside the enclosure supplied an adequate amount of water mist that could wash a part of the propane, resulting in the fuel concentration dropping below the lower explosion limit, hindering the occurrence of an explosion.

Analytical and Numerical Study of the Evaporation of a Single Fuel Droplet With a Vaporized Fuel Background

2008 ◽  
Author(s):  
Mehdi Abarham ◽  
Indrek S. Wichman
Keyword(s):  
Boundary Condition ◽  
Numerical Methods ◽  
Asymptotic Analysis ◽  
Numerical Study ◽  
Droplet Evaporation ◽  
Vapor Condensation ◽  
Stage I ◽  
Fuel Vapor ◽  
Fuel Droplet ◽  
Evaporation Stage

A simplified set of equations is examined for the problem of droplet evaporation. The equations employ the Clausius-Clapeyron boundary condition for the surface fuel-vapor condensation, which is responsible for numerous interesting mathematical behaviors, including the existence of an initial condensation stage followed by the classical d2-evaporation stage. Numerical methods of analysis are used, in conjunction with asymptotic analysis of each stage: (I) condensation; (II) transition; (III) evaporation. Comparisons are made with previous experiments. A brief discussion is provided of effective droplet evaporation in partial condensation environments.

scholarly journals Analysis of the Impact of Selected Parameters of the Hybrid Extinguishing System on the Fire Environment in a Closed Room

2019 ◽  
Vol 11 (23) ◽  
pp. 6867 ◽  
Author(s):  
Jerzy Gałaj ◽  
Tomasz Drzymała ◽  
Paweł Wolny
Keyword(s):  
Carbon Monoxide ◽  
Water Mist ◽  
Inert Gas ◽  
Fire Extinguishing ◽  
Fire Environment ◽  
Environment Temperature ◽  
Mist Flow ◽  
Characteristic Values ◽  
The Impact ◽  
Oxygen Concentrations

The main purpose of this study was to analyze the impact of some parameters (water mist flow rate and type of gas used) of the hybrid extinguishing system on the fire environment (temperature as well as carbon monoxide and oxygen concentrations) in a closed room. Hybrid fire-extinguishing systems in which water mist is driven by inert gas combine the advantages of typical fog systems and fixed gas extinguishing devices. They have been developed in the last years but are now being used more and more often and the preparation of standards for them is planned for 2020. For this purpose, many fire tests with this system should be conducted. Some of them are discussed in this paper. Two different flow rates of water mist (1.5 or 3 dm3/min) and inert gas (nitrogen or air) were used during hybrid system testing. Some parameters of the fire environment in the compartment such as temperature measured by thermocouples as well as carbon monoxide and oxygen concentrations measured by electrochemical gas sensors are presented here. The characteristic values of the extinguishing process are also included. The assumed times of ensuring safe conditions in the room have been confirmed.

scholarly journals Research on explosion suppression technology of low-concentration gas transmission pipeline

2021 ◽  
Vol 267 ◽  
pp. 01057
Author(s):  
Weizheng Wu
Keyword(s):  
Coal Mine ◽  
Water Mist ◽  
Inert Gas ◽  
Practical Significance ◽  
Low Concentration ◽  
Explosion Suppression ◽  
Coal Mine Gas ◽  
Transmission Pipeline ◽  
Mine Gas ◽  
Transmission Pipelines

In order to effectively control the explosion accident disasters of low-concentration gas transmission pipelines and improve the safety of low-concentration gas transmission and utilization process, the paper has summarized and analyzed the current three types of low-concentration gas transmission pipeline explosion suppression technologies and devices used in the field, including powder suppression, inert gas suppression and fine water mist suppression, and put forward the problems of coal mine gas transmission pipeline explosion suppression technologies. It is of great practical significance to pipeline transmission and utilization of low-concentration gas.

scholarly journals Assessment of extinguishing efficiency of hybrid system using water mist and inert gas during class A fires

2018 ◽  
Vol 247 ◽  
pp. 00013
Author(s):  
Jerzy Gałaj ◽  
Tomasz Drzymała
Keyword(s):  
Water Flow ◽  
Hybrid System ◽  
New Technology ◽  
Water Mist ◽  
International Standards ◽  
Inert Gas ◽  
Pipe System ◽  
Class A ◽  
Fire Extinguishing ◽  
The Impact

Fixed hybrid fire extinguishing system, a new technology used in fire protection all over the world in the last years, was discussed. A four-head twin pipe system supplied with water mist and inert gas (air or nitrogen) was applied. A pile of 50 pine wood boards was used as a combustible material (class A fire). It was located in the corner of the compartment while the nozzles were mounted symmetrically in the centre (volume suppression). The extinguishing processes differing in the proportion of water mist to gas were analysed. The extinguishing time was taken as the most important parameter indicating the extinguishing efficiency. The impact of water flow on extinguishing process was discussed. The clear dependence of extinguishing time on the water/gas ratio was proven. The best performance of the hybrid system at water flow 3 dm3/min and nitrogen as inert gas was observed. The results obtained during experiments can be useful in developing new international standards e.g. NFPA.

scholarly journals Cooling of a layered plate under mixed conditions

2000 ◽  
Vol 13 (2) ◽  
pp. 197-206
Author(s):  
F. D. Zaman ◽  
R. Al-Khairy
Keyword(s):  
Boundary Condition ◽  
Temperature Distribution ◽  
Mixed Boundary ◽  
Infinite Plate ◽  
Dissimilar Materials ◽  
Lower Surface ◽  
General Boundary ◽  
General Boundary Condition ◽  
Fluid Medium ◽  
The Fourier Transform

We consider the temperature distribution in an infinite plate composed of two dissimilar materials. We suppose that half of the upper surface (y=h,−∞<x<0) satisfies the general boundary condition of the Neumann type, while the other half (y=h,0<x<∞) satisfies the general boundary condition of the Dirichlet type. Such a plate is allowed to cool down on the lower surface with the help of a fluid medium which moves with a uniform speed v and which cools the plate at rate Ω. The resulting mixed boundary value problem is reduced to a functional equation of the Wiener-Hopf type by use of the Fourier transform. We then seek the solution using the analytic continuation and an extended form of the Liouville theorem. The temperature distribution in the two layers can then be written in a closed form by use of the inversion integral.

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