Coupling Analysis of the Flame Emission Spectra and Explosion Characteristics of CH₄/C₂H₆/Air Mixtures

Abstract

This work presents the coupling relationship between the flame emission spectra and explosion characteristics of CH 4 /C 2 H 6 /air mixtures ([CH 4 ] = 7.0, 9.5, and 11.0 vol %; [C 2 H 6 ] = 0−2.0 vol %). A 20 L spherical explosion testing system was used to record the explosion pressure−time curves of the CH 4 /C 2 H 6 /air mixtures at room temperature (18−22 °C) and pressure (1 atm). A flame emission detection system was used to capture the emission spectra of H* and OH* during the gas mixture explosions. In addition, sensitivity analysis was carried out on the change in the mole fraction of the explosion intermediates in a detailed mechanism (GRI-Mech 3.0). The results demonstrate that P max and (dP/dt) max increased with the addition of C 2 H 6 for the fuel-lean state, while the time to reach P max decreased with the addition of C 2 H 6 . For the stoichiometric and fuel-rich states, the opposite was true. Additionally, the trends of P max , (dP/dt) max , and time to reach P max are essentially in accordance with those of I max , (dI/dt) max , and time to reach I max for H* and OH*. Furthermore, on the basis of the sensitivity analysis, the C 2 H 6 addition has a positive effect on the production of OH* at the time corresponding to (dP/dt) max for the fuellean state, while the formation of OH* is inhibited by C 2 H 6 at the time to reach (dP/dt) max for the stoichiometric and fuel-rich states, which is consistent with the experimental results.

Coupling Analysis of Chemiluminescence and Pressure Changes in CH4/Air Explosion Suppressed by NaHCO3 Powder

“…She used the time difference between the peak explosion pressure and the peak CH 2 O concentration to measure the strength of their relationship. The coupling relationship has also been confirmed in the experimental study by Su . However, it has not been quantitatively analyzed, and the strength of the correlation between different particles and macroparameters has not been determined.…”

“…The coupling relationship has also been confirmed in the experimental study by Su. 36 However, it has not been quantitatively analyzed, and the strength of the correlation between different particles and macroparameters has not been determined.…”

“…The coupling relationship has also been confirmed in the experimental study by Su. 36 However, it has not been quantitatively analyzed, and the strength of the correlation between different particles and macroparameters has not been determined. In summary, the NaHCO 3 powder has a good suppression effect on methane combustion, and the chemiluminescence of certain excited radicals in the flame is significantly related to the combustion states of the flame.…”

Study on Soot Emission Characteristics of Methane/Oxygen Inverse Diffusion Flame

“…However, the abovementioned detection methods require additional equipment such as a laser, an external light source, and an optical lens group, which are relatively complex. Therefore, another kind of flame-based emission spectrum technology is adopted. , This method uses the flame spontaneous emission spectrum to detect hydrocarbon flame temperature, soot concentration, and radiation distribution characteristics, and its simplicity and efficiency have attracted increasing attention. The near-blackbody radiation generated by soot particles in the flame is located in the continuous radiation spectrum of visible and near-infrared bands .…”

Effects of Initial Temperature on the Deflagration Characteristics and Flame Propagation Behaviors of CH4 and Its Blends with C2H6, C2H4, CO, and H2

“…To date, extensive research has been conducted on the deflagration characteristics of methane − and suppression techniques. , The deflagration characteristics of other single gases, such as ethylene, propane, and hydrogen, have been extensively studied in the literature, − and the deflagration characteristics of mixtures of these gases have also been considered. − The explosive characteristics of flammable gas mixtures (explosion pressure ( P )/peak explosion pressure ( P max ) and pressure rise rate (d p /d t )/maximum pressure rise rate (d p /d t ) max )) are determined under various conditions (pressures and/or temperatures, concentration, humidity, explosive vessels of various volumes, and ignited by sources with various energies). The data refer to an individual fuel, such as hydrogen and gaseous alkane fuels, or a composite fuel (liquefied petroleum gas, gasoline, and ethanol). − For example, Razus experimentally measured the deflagration parameters of propane-air mixtures (2.50–6.20 %) in vessels of different shapes at various initial temperatures (298–423 K) and pressures (0.3–1.2 bar) . Mitu and Brandes reported the deflagration parameters of ethanol/air mixtures under different initial conditions .…”