scholarly journals The assessment of extinction mechanisms involving water mist applied to combustible liquids

2021 ◽  
Vol 30 (1) ◽  
pp. 54-63
Author(s):  
D. A. Korolchenko ◽  
S. V. Puzach
Keyword(s):  
Experimental Data ◽  
Energy Conservation ◽  
Conservation Laws ◽  
Water Flow ◽  
Water Mist ◽  
Mass Energy ◽  
Flame Zone ◽  
Mixed Gas ◽  
Fire Extinguishing ◽  
Combustible Liquids

Introduction. A number of problems accompany the development of new extinction methods applicable on the premises of buildings and structures and the use of advanced fire extinguishing agents. Subject-specific studies are needed to solve these problems. They include the identification of general principles of fire extinguishing efficiency and further development of the optimal mode of application of firefighting agents. The purpose of this work is the theoretical assessment of fire extinction mechanisms involving the water mist applied to combustible liquids. The objectives to be accomplished include the equations based on the mass/energy conservation laws and derived for flame zones with account taken of the water mist applied; the assessment of the water flow rate for different combustion mechanisms; comparison of assessment results with experimental data obtained in the process of extinguishing model fire seats that have burning combustible fluids.Methods of analysis. The calculations involve the equations based on the mass/energy conservation laws and derived for flame zones above the surface of combustibles.Research results. The author analyzes two fire extinguishing mechanisms that contribute to the suppression of burning in the flame zone: 1) the attainment of the value of mass concentration of water vapour that reaches the lower concentration limit of combustion of the combustible mixed gas (oxygen reduction); 2) cooling combustible mixed gas in the flame zone by evaporating water until the flash point temperature of combustible vapour is reached.Conclusions: Equations based on mass/energy conservation laws were derived for flame zones, formed in the course of combustion of flammable liquids, with account taken of a jet of water mist. Water flow rates needed for the implementation of various extinguishing mechanisms were analyzed using the proposed equations. Theoretical results were compared with the experimental data obtained in the process of using water mist to extinguish model fire seats that contain combustible fluids.

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 Effects of Discharge Area and Atomizing Gas Type in Full Cone Twin-Fluid Atomizer on Extinguishing Performance of Heptane Pool Fire under Two Heat Release Rate Conditions in an Enclosed Chamber

2021 ◽  
Vol 11 (7) ◽  
pp. 3247
Author(s):  
Dong Hwan Kim ◽  
Chi Young Lee ◽  
Chang Bo Oh
Keyword(s):  
Heat Release ◽  
Flow Rate ◽  
Heat Release Rate ◽  
Release Rate ◽  
Water Mist ◽  
Pool Fire ◽  
Sauter Mean Diameter ◽  
Discharge Area ◽  
Fire Extinguishing ◽  
Enclosed Chamber

In this study, the effects of discharge area and atomizing gas type in a twin-fluid atomizer on heptane pool fire-extinguishing performance were investigated under the heat release rate conditions of 1.17 and 5.23 kW in an enclosed chamber. Large and small full cone twin-fluid atomizers were prepared. Nitrogen and air were used as atomizing gases. With respect to the droplet size of water mist, as the water and air flow rates decreased and increased, respectively, the Sauter mean diameter (SMD) of the water mist decreased. The SMD of large and small atomizers were in the range of approximately 12–60 and 12–49 μm, respectively. With respect to the discharge area effect, the small atomizer exhibited a shorter extinguishing time, lower peak surface temperature, and higher minimum oxygen concentration than the large atomizer. Furthermore, it was observed that the effect of the discharge area on fire-extinguishing performance is dominant under certain flow rate conditions. With respect to the atomizing gas type effect, nitrogen and air appeared to exhibit nearly similar extinguishing times, peak surface temperatures, and minimum oxygen concentrations under most flow rate conditions. Based on the present and previous studies, it was revealed that the effect of atomizing gas type on fire-extinguishing performance is dependent on the relative positions of the discharged flow and fire source.

Numerical Simulation and Experimental Study on Water Mist Fire Suppression for Cooking Fog Discharge Pipe

2014 ◽  
Vol 915-916 ◽  
pp. 356-361
Author(s):  
Zheng Wen Xie
Keyword(s):  
Design Method ◽  
Fire Suppression ◽  
Orthogonal Design ◽  
Water Mist ◽  
Simulation Software ◽  
Droplet Radius ◽  
Test Analysis ◽  
Injection Angle ◽  
Fire Extinguishing ◽  
Flow Quantity

FDS simulation software was used to establish the full size lampblack physics model of single wind pipe, using the orthogonal design method design of analog calculation conditions, research in the nozzle pressure, the droplet radius, nozzle, flow quantity and injection angle parameters under different conditions of water mist fire extinguishing effect. Based on a full-scale combustion and water mist fire extinguishing experiment, the water mist fire suppression was observed and test analysis etc, to better understand the flue water mist fire extinguishing feasibility, provides the theory basis for the design of efficient, reliable flue fire extinguishing system.

The Experimental Study on the Fire Suppression Effectiveness of Water Mist with the FeCl2 Additives

2013 ◽  
Vol 790 ◽  
pp. 53-56
Author(s):  
Chen Jian ◽  
Xu Yan Ying ◽  
Wang Na
Keyword(s):  
Experimental Study ◽  
Fire Suppression ◽  
Water Mist ◽  
Experimental Results ◽  
Additive Concentration ◽  
Experimental Conditions ◽  
Fire Source ◽  
Fire Extinguishing ◽  
Nozzle Position

This paper presents an experimental study of fire suppression effectiveness with water mist containing FeCl2 additives.The investigation focuses on suppression effectiveness under various FeCl2 additives concentrations,working pressures and nozzle different height above the fire source . The experimental results show that: there is a significant impact on fire suppression effectiveness when adding FeCl2 to water mist. There is an optimum additive concentration of extinguishing fire, corresponding to the shortest extinguishing time, the least amount of water, the highest efficiency of extinguishing fire. The nozzle working pressures and nozzle position have effect on the performance of the water mist extinguishing: the greater the pressure is, the shorter water mist fire extinguishing time is. Under the same experimental conditions, the closer the water mist nozzles are to the oil pan, the shorter extinguishing time is.

Sign in / Sign up

Export Citation Format

Share Document