Study of Low-Pressure Premixed Dimethyl Ether/Hydrogen/Oxygen/Argon Laminar Flames with Photoionization Mass Spectrometry

Laminar premixed fuel-rich (equivalence ratio of 1.5) dimethyl ether/hydrogen/oxygen/argon flames with different hydrogen fractions (0%, 20%, 40%, 60%, and 80%) were investigated with tunable synchrotron vacuum-ultraviolet photoionization and molecular-beam mass spectrometry. The flame temperature profile was measured. Through measurement of the signal intensities at different distances from the burner surface, the mole fraction profiles of major intermediates are derived. A comparison of the flame temperature profiles or mole fraction profiles is made among these flames. The influences of hydrogen addition on the flame temperature and mole fractions of major species and intermediates are analyzed. The results show that the flame temperature in the flame zone decreases with an increase of hydrogen addition. The mole fractions of major species and intermediates are decreased with an increase of the hydrogen fraction. This might be attributed to the decrease of the C/H ratio of the fuel blend by hydrogen ad...