“…For example, Qi et al 49 and Zhang et al 36 divided the combustion behaviour for premixed methane-hydrogen into three modes. Wang et al 40 and Luo et al 48 also found similar laws in the combustion of a mixed gas of methane, ethylene, and ethane. Also found similar laws for the combustion of a mixed gas of methane, ethylene, and ethane.…”
Section: Resultsmentioning
confidence: 70%
“…However, the two sets of data have certain deviations in size. This difference is attributed to the heat loss in the experiment, which results in the experimental value being lower than the ideal value 48 . Figure 6 Explosion parameters for a methane–acetylene–air mixture [( a ) P max , ( b ) (d P /d t ) max , ( c ) T c , and ( d ) calculated pressure].…”
To study the impact of acetylene on methane explosions, the safe operation of coal mines should be ensured. In this paper, a 20 L spherical tank was used to study the explosive characteristics of acetylene–methane–air mixture. In addition, the GRI-Mech3.0 mechanism was used to study the chemical kinetic mechanism for the mixed gas, and the effect of adding acetylene on the sensitivity of methane and the yield of free radicals was analysed. The results show that acetylene can expand the scope for methane explosion, lower the lower explosion limit, and increase the risk of explosion. Acetylene increases the maximum explosion pressure, laminar combustion rate and maximum pressure rise rate for the methane–air mixture while shortening the combustion time. Three combustion modes for the acetylene–methane–air mixture were determined: methane-dominated, transitional and acetylene-dominated combustion modes. Chemical kinetic analysis for the mixed gas shows that as the volume fraction of acetylene increases, the generation rate for key free radicals (H*, O* and OH*) gradually increases, thereby increasing the intensity of the explosive reaction. The results from this research will help formulate measures to prevent coal mine explosion accidents.
“…For example, Qi et al 49 and Zhang et al 36 divided the combustion behaviour for premixed methane-hydrogen into three modes. Wang et al 40 and Luo et al 48 also found similar laws in the combustion of a mixed gas of methane, ethylene, and ethane. Also found similar laws for the combustion of a mixed gas of methane, ethylene, and ethane.…”
Section: Resultsmentioning
confidence: 70%
“…However, the two sets of data have certain deviations in size. This difference is attributed to the heat loss in the experiment, which results in the experimental value being lower than the ideal value 48 . Figure 6 Explosion parameters for a methane–acetylene–air mixture [( a ) P max , ( b ) (d P /d t ) max , ( c ) T c , and ( d ) calculated pressure].…”
To study the impact of acetylene on methane explosions, the safe operation of coal mines should be ensured. In this paper, a 20 L spherical tank was used to study the explosive characteristics of acetylene–methane–air mixture. In addition, the GRI-Mech3.0 mechanism was used to study the chemical kinetic mechanism for the mixed gas, and the effect of adding acetylene on the sensitivity of methane and the yield of free radicals was analysed. The results show that acetylene can expand the scope for methane explosion, lower the lower explosion limit, and increase the risk of explosion. Acetylene increases the maximum explosion pressure, laminar combustion rate and maximum pressure rise rate for the methane–air mixture while shortening the combustion time. Three combustion modes for the acetylene–methane–air mixture were determined: methane-dominated, transitional and acetylene-dominated combustion modes. Chemical kinetic analysis for the mixed gas shows that as the volume fraction of acetylene increases, the generation rate for key free radicals (H*, O* and OH*) gradually increases, thereby increasing the intensity of the explosive reaction. The results from this research will help formulate measures to prevent coal mine explosion accidents.
“…Increasing the packing density of gaseous fuel by pressurization will put forward special requirements for the warhead, thus liquid fuel is often chosen to overcome the challenge of the low charge density of gas fuel. Many academics have examined plenty of research on the explosion characteristics of fuel clouds [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Liu et al [33] studied the volatilization rate of pure and mixed combustible liquid fuels.…”
Fuel-air cloud explosions or detonations are often affected by initial ambient conditions. A two-dimensional (2D) semi-confined model was established to study the effects of the inflowing air temperature and initial temperature of the combustor on the explosion process of isopropyl nitrate (IPN)/air mixture. The results showed that at different initial temperatures (1000-3000 K), the first peak pressure (P 1 ) and second peak pressure (P 2 ) decreased with the increase in initial temperature; the maximum flame temperature (2338-3534 K) increased with the increasing initial temperature; the explosion pressure and temperature had the opposite trends with the initial temperature, indicating that the oxygen content in the combustor had a greater impact on the explosion pressure, while the initial temperature had a more significant effect on the flame temperature. Under different incoming air temperatures (1000-3000 K), the flame temperature (~2700 K) of the two-phase explosion had a small difference at the incoming temperature of � 2500 K, signifying that the airflow temperature (< 3000 K) and the oxygen content in air jointly dominated the flame temperature; the flame temperature was 3100 K at the incoming temperature of 3000 K, which was about 300 K higher than other incoming flow temperatures, indicating that the flame temperature was more sensitive to the incoming air temperature (� 3000 K). At 600 m/s airflow, the explosion parameter curves at the inflow temperatures of 300 K and 600 K were compared, and the critical inflow temperature of the explosion process was also investigated.
“…The explosion limit of O 2 /CO 2 /CH 4 mixtures and CH 4 -air , can be calculated based on thermal theory and thermal radiation effects. The upper explosion limit of methane was slightly reduced when the pressure was increased, and the addition of C 2 H 6 reduced both the upper and lower explosion limits of CH 4 . Chen et al investigated the dilution effect of CO 2 , N 2 , and Ar on various fuels and analyzed the impact of CO 2 on combustion chemistry kinetics.…”
Section: Introductionmentioning
confidence: 99%
“…The upper explosion limit of methane was slightly reduced when the pressure was increased, 35 and the addition of C 2 H 6 reduced both the upper and lower explosion limits of CH 4 . 36 Chen et al 37 investigated the dilution effect of CO 2 , N 2 , and Ar on various fuels and analyzed the impact of CO 2 on combustion chemistry kinetics. Wang et al 38 studied the effect of sudden change of duct cross-sectional area on flame propagation of methane/air premixed gas.…”
To investigate the effect of concentration of N 2 and CO 2 (0, 10, 20, 30, 40, and 50%) on the flame propagation characteristics of CH 4 /air premixed gases with stoichiometric ratios in variable cross-section ducts, experiments were conducted in four combinations of ducts at initial conditions of 298 K and 1 atm. The results show that the flame propagation velocity, propagation time, and overpressure are greater in the suddenly contracted duct than in the suddenly expanded duct if the dimensions of the ducts are kept constant. However, an increase in inert gas concentration leads to a decrease in flame propagation speed, an increase in flame propagation time, and changes in flame structure and pressure. "Tulip" flames appeared when a duct with a cross section of 100 mm × 100 mm was combined with a duct with a cross section of 70 mm × 70 mm, whether N 2 or CO 2 was added or what its concentration was. However, when a duct with a cross section of 140 mm × 140 mm was combined with a 70 mm × 70 mm duct, a "tulip" flame is formed only at a CO 2 concentration of 50%. As the concentration of inert gas increases, the explosion pressure first decreases and then stabilizes, while the rate of pressure increase showed a monotonically decreasing trend. The explosion pressure is minimized when the concentration of CO 2 and N 2 is 30 and 40%, respectively.
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