The upper flammability limit of methane/hydrogen/air mixtures at elevated pressures and temperatures

Calculation of the upper flammability limit of methane/air mixtures at elevated pressures and temperatures

“…Throughout the calculations it is assumed that the gas mixture is ideal and that the pressure is constant in space and time. These are valid approximations since the compressibility factor Z ≈ 1.00 for the mixtures under consideration [12] and since the pressure increase during near-limit 0304 flame propagation is limited to approximately 5 % of the initial pressure [10]. Further details about the flame code can be found elsewhere [13].…”

“…This ignition source is modelled as an energy input of 10.5 J during a period of 40 ms in a spherical volume with a diameter of 10 mm. These parameters are chosen to resemble the ignition source that is used in the experiments [10] with which the calculations will be compared. Mixtures in which flames propagate a distance of 100 mm are considered to be flammable.…”

“…8. Comparison of the experimentally determined upper flammability limit (markers) [10] and the temperature dependence estimated based upon the limiting flame temperature approach (solid lines) for methane/air flames. flammability limits decrease by approximately 150 • C in the pressure range 1-10 bar (Table 3).…”

“…It was found among others that the estimates of the flammability limits become more accurate as more flame aspects are taken into account by the calculations. To further corroborate the previous findings, the focus of this study will be on the upper flammability limits of methane/air mixtures at initial pressures up to 10 bar and initial temperatures up to 200 • C. To this end, the results of the different numerical methods -namely the calculation of planar [2][3][4][5] and of spherical [6] flames with the inclusion of a (radiation) heat loss term in the energy conservation equation, and the application of a limiting burning velocity [4,7] and of a limiting flame temperature [8,9] -will be compared with experimental data [10].…”

An experimental study on hydrogen–methane mixtured fuels

“…They found that the hydrogen oxidation kinetic significantly interacts with methane Mild Combustion process. Other applications with related the present study can be found in open literature [12][13][14][15].…”