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.

scholarly journals Orthogonal Design Method for Optimizing Roughly Designed Antenna

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Qing Zhang ◽  
Sanyou Zeng ◽  
Chunbang Wu
Keyword(s):  
Design Method ◽  
Orthogonal Design ◽  
Simulation Software ◽  
Specific Region ◽  
Antenna Design ◽  
Wire Antenna ◽  
Real World Application ◽  
Orthogonal Design Method ◽  
Numerical Electromagnetics ◽  
Geometrical Factors

Orthogonal design method (ODM) is widely used in real world application while it is not used for antenna design yet. It is employed to optimize roughly designed antenna in this paper. The geometrical factors of the antenna are relaxed within specific region and each factor is divided into some levels, and the performance of the antenna is constructed as objective. Then the ODM samples small number of antennas over the relaxed space and finds a prospective antenna. In an experiment of designing ST5 satellite miniantenna, we first get a roughly evolved antenna. The reason why we evolve roughly is because the evolving is time consuming even if numerical electromagnetics code 2 (NEC2) is employed (NEC2 source code is openly available and is fast in wire antenna simulation but not much feasible). Then the ODM method is employed to locally optimize the antenna with HFSS (HFSS is a commercial and feasible electromagnetics simulation software). The result shows the ODM optimizes successfully the roughly evolved antenna.

New techniques and a new approach to the effective extinguishing of fully developed fires in enclosed spaces

2016 ◽  
Vol 8 (1) ◽  
pp. 213-224
Author(s):  
Norbert Tuśnio ◽  
Paweł Wolny
Keyword(s):  
Fire Suppression ◽  
Radiant Heat ◽  
Fire Service ◽  
Water Mist ◽  
Abrasive Waterjet ◽  
Water Spray ◽  
Fire Extinguishing ◽  
Pressure Water ◽  
Fire Area ◽  
In Fire

An example of modern water mist extinguishing technology is presented in the article. Water mist systems are firefighting systems which uses very fine water sprays. The smallest water droplets allow a water mist to control, suppress or extinguish fires by cooling both the flame and hot gases by evaporation, displacing oxygen by evaporation and reducing radiant heat through the small droplets themselves. The effectiveness of water mist systems in fire suppression depends on its spray characteristics, which include the droplet size and distribution, flux density and spray dynamics, phase of fire development, fire size and the ventilation conditions. The COBRA (known as PyroLance in USA) systems presented use of a cutting extinguisher is a fire extinguishing technique that combines abrasive waterjet cutting with water spray extinguishing, through a single handpiece or nozzle. The firefighter approaches the fire from outside the main fire area, then uses the cutting action to drill a small hole through a barrier such as a door, wall, roof or floor. Switching to a water spray then allows the fire to be fought, as with a conventional fog nozzle. An analysis of the benefits of using high-pressure water mist in conjunction with new firefighting tactics is described. State Fire Service should aim to minimize water consumption and thus reduce the post-fire losses, take care of environmental protection and improve safety conditions for firefighters.

Experimental and Numerical Study on the Suppression of Pool Fire with Water Mist

2013 ◽  
Vol 790 ◽  
pp. 686-689
Author(s):  
Chen Jian ◽  
Xu Yan Ying ◽  
Wang Yan Sheng
Keyword(s):  
Systems Engineering ◽  
Numerical Study ◽  
Fire Suppression ◽  
Inhibitory Effect ◽  
Water Mist ◽  
Pool Fire ◽  
Optimized Design ◽  
Operating Pressure ◽  
Fire Extinguishing ◽  
Oil Pool

The objective of this work is to investigate the diesel analog pool fire with water mist .For this purpose, a series of water mist fire suppression experiment are carried out by changing the nozzle operating pressure, the source of fire power, opening and closing the exhaust fan to analyze the inhibitory effect of water mist to oil pool fire in the enclosed compartment of 5.0m × 5.0m × 3.0m. The results shows that extinguishing efficiency first increases and then decreases when the nozzle operating pressure increases from 8MPa to 12MPa, reaching the highest efficiency at 10MPa; increasing the power of the source of fire, the burning speed increases and the water mist fire extinguishing efficiency decreases; fresh oxygen coming in when smoke exhaust fan is turned on and water mist fire suppression efficiency decreases. Using FDS to simulate the water mist extinguishing oil pool fire, the predict temperature field and extinguishing time are basically consistent with the experimental results. In the actual applications of water mist fire suppression systems engineering, we can use the FDS field simulation methods to predict the characteristic parameters variation of the fire fighting fire temperature and component concentration, which is significant to the fire extinguishing system optimized design.

The Double-Diffusive Convection in the Process of Water Mist Fire Suppression

2008 ◽  
Author(s):  
Kai Xu ◽  
Wen-Qiang Lu
Keyword(s):  
Fire Suppression ◽  
Co2 Concentration ◽  
Water Mist ◽  
Droplet Radius ◽  
Water Spray ◽  
Double Diffusive Convection ◽  
Smoke Movement ◽  
Thermal Buoyancy ◽  
Diffusive Convection ◽  
Double Diffusive

In the research of the mechanism of water mist fire suppression, thermal buoyancy has important effects on smoke movement and temperature distribution, but the effects of the smoke diffusion are less considered. In this paper, a computational method couple dual reciprocity boundary element method (DRBEM) with finite volume method (FVM) is developed to study the thermal and smoke diffusion effects on the smoke movement, temperature and CO2 concentration distribution. And the interaction between the smoke and a water spray is calculated using FVM with the PSIC scheme. The DRBEM is employed to calculate the inner temperature of the droplet and radius variation, and the results show that when the droplet radius less than 1mm, the uniformly temperature assumption is reasonable. Numerical results also show the gradients of temperature and smoke concentration drive double-diffusive convection have different effects on the smoke temperature and CO2 concentration with and without water spray.

A Numerical Study Onfire Suppression of Water Mist in Microgravity

2014 ◽  
Vol 1016 ◽  
pp. 819-823
Author(s):  
Xue Han ◽  
Jun Qin ◽  
Jun Jun Tao ◽  
Ming Hui Feng
Keyword(s):  
Flow Rate ◽  
Numerical Study ◽  
Fire Suppression ◽  
Water Flow Rate ◽  
Simulation Method ◽  
Critical Value ◽  
Water Mist ◽  
Dominant Mechanism ◽  
Effect Of Water ◽  
Fire Extinguishing

Water mist technology has been developed and regarded as a promising substitute fire-extinguishing agent in spacecraft. In this paper, a numerical simulation method is introduced to investigate the effect of water mist size, velocity and flow rateon the fire suppressionefficiencyin microgravity. The fire extinguishing efficiency is better for the finer water mist in microgravity due to better heat transfer and more rapid vaporization. The evaporation cooling is the dominant mechanism of fire suppression in microgravity.As for the water mist velocity, the performance of fire suppression is affected slightly in microgravity. The results on the effect of water flow rate show that the flow rate should be higher than a critical value to suppress the fire effectively.

A Study on the New Portable Effervescent Atomized Water Mist Equipment

2013 ◽  
Vol 392 ◽  
pp. 116-121
Author(s):  
Qiang Liang ◽  
Yan Feng Li ◽  
Guo Cai Yao ◽  
Xue Fei Xing
Keyword(s):  
Heat Flux ◽  
Fire Suppression ◽  
Water Mist ◽  
Pool Fire ◽  
Radiation Heat ◽  
Radiation Heat Flux ◽  
Wood Crib ◽  
Fire Extinguishment ◽  
Fire Extinguishing ◽  
Atomized Water

A new effervescent atomized water mist fire extinguishing equipment was developed by combining the characters of water mist and effervescent atomization. A series of wood crib and gasoline pool fire suppression experiments were performed using the equipment. The fire extinguishment time, temperature and radiation heat flux of the flame were measured, and then the process of putting out different type fire was analyzed. A wood crib fire of 0.6A can be put out in 180 seconds using water mist produced by effervescent atomization equipment. Only 38 seconds was taken to suppress a gasoline fire.

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