Numerical simulation of methane explosion suppression by ultrafine water mist in a confined space

Explosion suppression by water mist is a new technology for the control of coal mine gas explosion with the three elements in the gas explosion at the same time. By building the physical model of the horizontal laneway in mine, and using the method of theoretical research and numerical simulation, this paper studies the relationship between the number of nozzles and H2O percentage and the distance for stable percentage of H2O, and provides a reliable for the design of water mist system for gas explosion suppression in the horizontal laneway in mine.

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Effect of Pristine Palygorskite Powders on Explosion Characteristics of Methane-Air Premixed Gas

Energies ◽

10.3390/en11102496 ◽

2018 ◽

Vol 11 (10) ◽

pp. 2496 ◽

Cited By ~ 4

Author(s):

Yimin Zhang ◽

Yan Wang ◽

Ligang Zheng ◽

Tao Yang ◽

Jianliang Gao ◽

...

Keyword(s):

Flame Propagation ◽

Low Cost ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Flame Propagation Velocity ◽

Explosion Pressure ◽

Pyrolysis Characteristics ◽

Explosion Suppression ◽

Adsorption Desorption ◽

Methane Explosion

In this study, pristine palygorskite powders were used as the inhibition materials to suppress the explosion of methane-air premixed gas for the first time. The composition, porosity and pyrolysis characteristics of the powders were tested by X-ray diffraction (XRD), energy dispersive spectrometry (EDS), N2 adsorption-desorption and Thermogravimetry-differential scanning calorimetry (TG-DSC) techniques. The effects of pristine palygorskite powders concentration on the explosion pressure and the average velocity of flame propagation of the 9.5% methane-air premixed gas were tested by a 20 L spherical explosion system and a 5 L pipeline explosion system. The results indicated the pristine palygorskite powders possess a considerable suppression property on methane explosion. When the mass concentration of pristine palygorskite powders was 0.20 g·L−1, the max-pressure of methane explosion was decreased by 23.9%. The methane explosion flame propagation velocity was inhibited obviously. Owing to the excellent inhibitory performance and the advantage of low-cost and environmental harmlessness, pristine palygorskite powders are potential new materials for the application on gas explosion suppression.

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Experimental Study on Water Mist Suppression of Poly(Methyl Methacrylate) PMMA Fires

Volume 4 ◽

10.1115/ht-fed2004-56674 ◽

2004 ◽

Author(s):

B. Yao ◽

J. Qin ◽

W. K. Chow

Keyword(s):

Methyl Methacrylate ◽

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Water Mist ◽

Doppler Velocimetry ◽

Confined Space ◽

Surface Cooling ◽

Fuel Surface ◽

Poly Methyl Methacrylate

Suppression of Poly(methyl methacrylate) PMMA fires by water mist will be studied in this paper. A simple test is developed to study the critical water flow rate under different radiant heat flux. The test is found to be suitable for studying the extinguishment effects of fine water droplets involving oxygen displacement, gas phase and fuel surface cooling. Water mist is generated by a single pressure nozzle, with the water mist characteristics measured by the Laser Doppler Velocimetry or the Adaptive Phase Doppler Velocimetry System (LDV/APV system). The interaction between water mist and the PMMA flame will be studied in a confined space with ventilation control in a cone calorimeter. The heat release rate, oxygen, carbon dioxide and carbon monoxide concentrations, and other important parameters of the interaction under various conditions are measured. It is found that discharging adequate amount of water mist would suppress the diffusion flame in the confined space. Reignition might occur once water mist stopped discharging to the fuel surface. Higher heat release rate and more smoke and toxic gases were produced than from those in first ignition.

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