Shock Tube Measurements and Modeling Study on the Ignition Delay Times of n-Butanol/Dimethyl Ether Mixtures

Abstract

The ignition delay times of different n-butanol/dimethyl ether (DME) mixtures (DME mole ratios of 100%, 80%, 60%, 40%, and 0%) were studied behind reflected shock waves at equivalence ratios of 0.5, 1.0, and 1.5; pressures of 6.0, 10, and 15 bar; temperatures of 1150−1650 K. The effects of a carrier gas (nitrogen or argon) on the ignition delay times of single and blended fuels were also studied. The chemical kinetic mechanism of DME/n-butanol was established based on Zhao's DME chemical kinetic mechanism (Int. J. Chem. Kinet. 2008, 40, 1−18) and Strathy's n-butanol chemical kinetic mechanism (Combust. Flame 2012, 159, 2028−2055, which can accurately predict the ignition delay times of both single and blended fuels. Experimental results show that the ignition delay time of DME is longer than that of n-butanol when the temperature is high (>1150 k) and that the ignition delays of blended fuels increase with an increased blending ratio of DME. However, the relationship between ignition delay time and the blending ratio is nonlinear. The main factor affecting the blended fuel's ignition delay is temperature, and with every 200 °C increase in temperature, the ignition delay times is reduced by an order of magnitude. Additionally, pressure has a large effect on the ignition delay times. The results of reaction path analysis of blended fuels show that with an increasing DME blending ratio, the contribution rate of OH-radicals to H-abstraction decreases during the oxidation of n-butanol, and the contribution rate of H-radicals to H-abstraction of n-butanol increases slightly. However, with an increasing DME blending ratio, the pyrolysis of DME decreases, but the contribution rate of CH 3 and OH to the Habstraction of DME increases.

A Shock Tube Experimental and Modeling Study of Multicomponent Gasoline Surrogates Diluted with Exhaust Gas Recirculation

“…All of the ignition delay experiments were performed in an unheated high-pressure shock tube facility with 90 mm inner diameter, which was described and tested in detail in references. − The shock waves were produced by the rupture of diaphragm, and the arrival of the incident and reflected waves were detected by six piezo-electric pressure transducers (PCB113B26) positioned axially along the driven section, whereas the OH* emission was detected by a photomultiplier (Hamamatsu, R928). The purities of all gases (N 2 , O 2 , He, CO 2 ) used in this study were 99.999%, toluene, isooctane, and cyclohexane were 99.5%, n -heptane was 99.9%.…”

Auto-ignition of biomass synthesis gas in shock tube at elevated temperature and pressure

“…Previous studies [46,47] have given a detailed introduction of the apparatus and validated the reliability and repeatability of it. The apparatus is primarily composed by a 6-m-long driving section (inner diameter of 90 mm), a 5-m-long driven section (inner diameter of 90 mm) and a diaphragm section (the material of diaphragms is polyethylene terephthalate).…”

Experimental and Kinetic Study on Ignition Delay Times of Liquified Petroleum Gas/Dimethyl Ether Blends in a Shock Tube

“…In this study, all measurements were carried out in a shock tube whose description and reliability analysis were given in detail in a previous study. 35 The homogeneous fuel mixtures were prepared in a 210 L stainless steel tank according to Dalton's law of partial pressure. All fuels are gases at environmental temperature, and then they can become sufficiently mixed by being settled down for at least 2 h. The shock tube is divided into a 6 m long driver section and a 5 m long driven section by polyethylene terephthalate (PET) diaphragms.…”

“…In this study, all measurements were carried out in a shock tube whose description and reliability analysis were given in detail in a previous study . The homogeneous fuel mixtures were prepared in a 210 L stainless steel tank according to Dalton’s law of partial pressure.…”