Experimental Study on Premixed Combustion of Dimethyl Ether–Hydrogen–Air Mixtures

Abstract

The laminar combustion characteristics of DME–hydrogen–air premixed mixture were studied at different equivalence ratios, ratios of hydrogen to DME plus hydrogen, and initial pressures by using a constant volume combustion bomb. The influences of the equivalence ratio, the hydrogen addition, and the initial pressure on flame speed and combustion characteristics are analyzed. The results show that the flame speed, the laminar burning velocity, and the mass burning rate increase with the increase of hydrogen addition. Increasing the ratio of hydrogen to DME plus hydrogen will shorten the combustion duration. In the case of small hydrogen addition, the Markstein length decreases with the increase of equivalence ratio, and this reveals that lean mixture has better flame front stability compared with that of the rich mixture. In the case of large hydrogen addition, the Markstein length increases with the increase of equivalence ratio, and this indicates that the rich mixture has better flame front stability than the lean mixture. Maximum combustion pressure increases with the increase of initial pressure, and initial pressure has larger influence on combustion pressure than that from hydrogen addition. The flame development duration decreases with the increase of hydrogen addition and the increase of equivalence ratio.

Effects of Hydrogen Addition on the Laminar Flame Speed and Markstein Length of Premixed Dimethyl Ether–Air Flames

“…Liu et al , numerically studied the effects of hydrogen addition on the intermediate species of premixed DME–oxygen–argon flames and the chemical effect of hydrogen addition, respectively. Huang et al experimentally studied the laminar flame speeds of DME/H 2 /air mixtures at three equivalence ratios (0.8, 1.0, and 1.2) and normal temperature and pressure. Chen et al studied the effects of hydrogen addition on mole fractions of major intermediates and main products of premixed fuel-rich (ϕ = 1.5) DME/H 2 /O 2 /Ar flames using molecular beam sampling mass spectrometry techniques and tunable synchrotron vacuum ultraviolet photoionization.…”

Effect of pressure and equivalence ratio on the ignition characteristics of dimethyl ether-hydrogen mixtures

“…These experimental data are of great worthy for the validation of the hydrocarbon kinetic mechanism. The experimental studies showed that addition of hydrogen to hydrocarbons could shorten the ignition delay time [14,32,36] at high temperature and increase the flame speed [16,37,38]. It is clear that the previous studies on the ignition delay times mainly concentrated on the influence of hydrogen addition, and little data are available on the effect of pressure and equivalence ratio.…”

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

“…As the hydrogen fraction in the premixed mixture was increased, the heat release of the unit volume mixture decreased. Meanwhile, the burning velocities of H 2 /DME blend fuels increased with an increase of the hydrogen fraction . The higher flame velocity resulted in more heat transfer to the burner.…”

“…Meanwhile, the burning velocities of H 2 /DME blend fuels increased with an increase of the hydrogen fraction. 21 The higher flame velocity resulted in more heat transfer to the burner. The above two facts 6 Because the first sampling position was 1.0 mm apart from the burner surface to prevent the sampling nozzle from being destroyed, DME and O 2 were fractionally consumed and there were certain amounts of products of H 2 , H 2 O, CO, and CO 2 at the first sampling position.…”

“…Experimental and numerical studies of DME/air − or H 2 /air premixed flames have been extensively carried out. However, except for a few works on the fundamental studies of DME/H 2 mixtures, few studies reported the measurement of combustion intermediates of DME/H 2 blended fuel flames. To understand the details of hydrogen addition to the DME flames, the measurement of combustion intermediates of a DME/H 2 blend is needed.…”