scholarly journals Study on Influence of Cavity and Water Mist on Flame Propagation of Gas Explosion in a Pipeline

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Shicheng Gu ◽  
Shujie Yuan ◽  
Zhuo Yan ◽  
Xiaoxue Xu
Keyword(s):  
Flame Propagation ◽  
Propagation Speed ◽  
Water Mist ◽  
Rectangular Cavity ◽  
Heat Absorption ◽  
Gas Explosion ◽  
Flame Propagation Velocity ◽  
Velocity Increase ◽  
Influence Of Water ◽  
Better Than

For studying the influence of the cavity and water mist on the flame propagation of gas explosion, a rectangular steel cavity of size of length 80   cm × width   50   cm × height   20   cm was designed. The influence of the cavity and it with water mist on explosion flame propagation in a large circular gas explosion system with a length of 34 m was studied. The change of gas explosion flame in the pipeline was analyzed. The results showed that the intensity and flame propagation velocity increase after the explosion flame passes through the straight pipeline, and the attenuation rates are 4.93% and -2.48%, respectively. After the explosion flame passes through a rectangular cavity of length 80   cm × width   50   cm × height   20   cm , its intensity and propagation speed are inhibited, and the attenuation rates are 66.58% and 45.26%, respectively. After the explosion flame passes through the rectangular cavity of the size of length 80   cm × width   50   cm × height   20   cm with water mist, the intensity and propagation speed are inhibited much more, and the attenuation rates are 85.09% and 65.85%, respectively. The influence of the cavity with water mist on flame attenuation of gas explosion is better than that of the cavity alone. Based on theoretical analysis, it is concluded that the inhibition influence of the cavity on explosion flame propagation is mainly due to repeated reflection of flame in the cavity, which results in the attenuation of its energy. The inhibition influence of water mist is mainly due to its heat absorption by vaporization.

scholarly journals C114 Effect of Flame Propagation Speed on Gas Explosion

2014 ◽  
Vol 2014 (0) ◽  
pp. _C114-1_-_C114-2_
Author(s):  
Toshio Mogi ◽  
Wookyong Kim ◽  
Ritsu Dobashi
Keyword(s):  
Flame Propagation ◽  
Propagation Speed ◽  
Gas Explosion ◽  
Flame Propagation Speed

scholarly journals Numerical Simulation of Interaction between Large-Scale Congestion and Vent during the Natural Gas Explosion in a Kitchen

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Lei Pang ◽  
Mengjie Jin ◽  
Qianran Hu ◽  
Kai Yang
Keyword(s):  
Natural Gas ◽  
Flow Field ◽  
Flame Propagation ◽  
Combustion Rate ◽  
Large Scale ◽  
Small Scale ◽  
Propagation Mode ◽  
Gas Explosion ◽  
Flame Propagation Velocity ◽  
Explosion Process

The influence of large-scale congestion on a confined natural gas explosion in a typical Chinese kitchen was studied using the computational fluid dynamics technology. It was found that opening the explosion venting surface promotes the development of turbulence, flame propagation velocity, and multipeak overpressure in the explosion flow field. Large-scale congestion can significantly strengthen the influence of the explosion venting surface on the flow field; the congestion and the explosion venting surface have a synergistic effect on the explosion flow field. At the moment of gas explosion, the flow fields in each area of the kitchen exhibit different distribution characteristics. A flow field near small-scale congestion is more likely to produce greater turbulence, combustion rate, and flame speed. The obstruction effect of large-scale congestion perpendicular to the flame propagation direction is dominant. The indoor flame propagation speed and overpressure development speed increase and the peak combustion rate and indoor peak overpressure decrease with an increase in obstacle blockage. Increases in the large-scale volume congestion rate and volume blockage in the kitchen induce changes in the indoor flame propagation mode and increase the external explosion overpressure. This paper investigated the correlation behavior between large-scale congestion and vent surface in a typical Chinese civil kitchen during natural gas explosion process and provided important support for understanding the mechanism of congestion on gas explosion process and the distribution of explosion hazards in a kitchen.

scholarly journals Numerical simulation of the influence of pipe length on explosion flame propagation in open-ended and close-ended pipes

2020 ◽  
Vol 103 (4) ◽  
pp. 003685042096160
Author(s):  
Xue Li ◽  
Ning Zhou ◽  
Xuanya Liu ◽  
Weiqiu Huang ◽  
Bing Chen ◽  
...  
Keyword(s):  
Flame Front ◽  
Flame Propagation ◽  
Flame Structure ◽  
Great Influence ◽  
Propagation Speed ◽  
Rapid Expansion ◽  
Combustion Model ◽  
Pipe Length ◽  
Flame Propagation Velocity ◽  
Tulip Flame

The pipeline length exerts great influence on flame propagation characteristics, Realizable [Formula: see text] model and Premixed combustion model were used to study the influence of pipe length on propane-air explosion flame in open-ended and close-ended pipes. Using the numerical model verified by experiments, the changes of flame structure and flame propagation speed are studied. The result showed that the Realizable model was in good agreement with the experimental results. It also proved that the reflected wave produced a strong interference on the flame front, which promoted the formation of tulip flame. Besides, some obvious vortices were usually generated in the burned gas after the tulip flame formed, which will affect the flow field around the flame front and thus exert influence on the flame structure. The formation mechanism of tulip flame as well as the flame self-acceleration is different in open-ended and close-ended pipes. In close-ended pipes, the reflection wave at the pipe end and the reflection-induced countercurrent both promote the formation of tulip flame. As the flame propagates to the pipe end, the flame propagation is inhibited by the compression wave formed by the rapid expansion of combustion products under high temperature. While, in open-ended pipes, the turbulence induced by the opening at the pipe end is the main cause of tulip flame formation. The flame acceleration depends on the combustion reaction of unburned gas, so the velocity of flame propagation continues to increase. Generally, the maximum flame propagation velocity in the open-ended pipe is larger than that in the close-ended pipe.

scholarly journals Natural Gas-Oxygen Combustion in a Super-Critical Carbon Dioxide Gas Turbine Combustor

2020 ◽  
Vol 178 ◽  
pp. 01027
Author(s):  
Ivan Komarov ◽  
Daria Kharlamova ◽  
Bulat Makhmutov ◽  
Sofia Shabalova ◽  
Ilya Kaplanovich
Keyword(s):  
Carbon Dioxide ◽  
Gas Turbine ◽  
Chemical Kinetics ◽  
Flame Propagation ◽  
Propagation Velocity ◽  
Critical Pressure ◽  
Fuel Cycle ◽  
Flame Propagation Velocity ◽  
Velocity Increase ◽  
Carbon Dioxide Gas

The paper presents results for chemical kinetics of combustion process in the combustor of oxy-fuel cycle super-critical carbon dioxide gas turbine based on the Allam thermodynamic cycle. The work shows deviation of the normal flame propagation velocity for the case of transition from the traditional natural gas combustion in the N2 diluent environment to the combustion at super-high pressure up to 300 bar in CO2 diluent. The chemical kinetics parametric study involved the Chemkin code with the GRI-Mesh 3.0 kinetic mechanism. This mechanism provides good correspondence between calculation results and test data. The CO2 and N2 diluents temperature, pressure and contents influence the flame propagation velocity and the chemical kinetics parameters in the two gas turbine types. It is demonstrated that the CO2 diluent slows down chemical reactions stronger than the N2 one. The flame propagation velocity in carbon dioxide is four time smaller than in the N2 one. In the oxy-fuel cycle combustor a pressure increase reduces the flame propagation velocity. Increase of the CO2 content from 60 to 79% reduces the flame propagation velocity for 65% at atmospheric pressure and for 94% at super-critical pressure. An increase of the combustor inlet mixture temperature from 300 to 1100 K at super-critical pressure causes the flame propagation velocity increase for 94%. The flame propagation velocities compatible with the traditional gas turbines may be reached at the CO2 diluent content of the O2 + CO2 mixture in the active combustion zone must be below 50%.

scholarly journals Suppression of Deflagration Flame Propagation of Methane-Air in Tube By Argon Gas and Explosion-Eliminating Chamber

2021 ◽  
Author(s):  
Quan Wang ◽  
Xiaomeng Xu ◽  
Weida Chang ◽  
Zhimin Li ◽  
Jun Zhang ◽  
...  
Keyword(s):  
Flame Propagation ◽  
Flame Structure ◽  
Propagation Speed ◽  
Inhibitory Effect ◽  
Test System ◽  
Experimental Conditions ◽  
Flame Propagation Velocity ◽  
Argon Gas ◽  
Average Value ◽  
Flame Propagation Speed

Abstract To explore the inhibitory effect of argon gas and explosion-eliminating chamber on methane-air deflagration flame propagation in the tube, based on the Φ=120 mm, L=5.5 m stainless steel pipeline test system to measure methane-air deflagration flame structure, flame propagation speed, and deflagration pressure. The results show that: 10%~30% argon is mixed into the methane-air premixed gas with different equivalent ratios. With the increase in the mixed argon content, the tensile distortion and instability of the flame front increase, and the average value of flame propagation speed decreases by 2.52%~60.0%. The first and second deflagration pressure peaks are reduced by about 13.1%~62% and 17.7%~86.5% respectively. The average value of the methane-air deflagration flame propagation velocity was reduced by 5.7%~37.0% with the explosion-eliminating chamber laid at the nozzle. The second and third deflagration pressure peaks are reduced by about 10%~30% and 50%~90% respectively. The inhibitory effect of argon on the propagation of methane-air flame is considered better than the laying of the explosion-eliminating chamber under the experimental conditions.

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

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2496 ◽  
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.

Ignition Dynamics in an Annular Combustor With Gyratory Flow Motion

2018 ◽  
Author(s):  
Chenran Ye ◽  
Gaofeng Wang ◽  
Yuanqi Fang ◽  
Chengbiao Ma ◽  
Liang Zhong ◽  
...  
Keyword(s):  
Flame Propagation ◽  
Velocity Component ◽  
Thermal Power ◽  
Propagation Speed ◽  
Circumferential Velocity ◽  
Bulk Velocity ◽  
Ignition Process ◽  
Flow Motion ◽  
Annular Combustor ◽  
Flame Propagation Speed

In concepts of integrated design of combustor and turbine, an annular combustor model is developed and featured with multiple oblique-injecting swirling injectors to introduce gyratory flow motion in the combustion chamber. The ignition process is experimentally investigated to study the effects of introducing circumferential velocity component Uc to the light-round sequence. Experiments are carried out with premixed propane/air mixture in ambient conditions. The light-round sequence is recorded by a high-speed camera, which provides detailed flame azimuthal positions during the sequence and gives access to the light-round time τ and the circumferential flame propagation speed Sc. The results have also been compared with that obtained from a straight-injecting annular combustor. The effects of bulk velocity Ub, thermal power P and equivalence ratio Φ are also explored. Due to the gyratory flow motion induced by oblique injection, the flame fronts only propagate along the direction of circumferential flow. Both of the circumferential flame propagation speed increase with increasing bulk velocity in two injection types. It seems mainly to depend on bulk velocity, regardless of Φ, in oblique-injecting combustor when compared with the straight one. It indicates that the circumferential velocity component would play a dominant role in light-round sequence when it is sufficient higher than the displacement flame speed.

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