Ignition delay times of diethyl ether measured in a high-pressure shock tube and a rapid compression machine

Werler, Marc; Cancino, Leonel R; Schießl, Robert; Maas, Ulrich; Schulz, Christof; Fikri, Mustapha

doi:10.1016/j.proci.2014.06.143

Cited by 77 publications

(52 citation statements)

References 23 publications

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“…The mixture in the reactor cylinder is compressed by a rapidly moving piston and then it ignites spontaneously (autoignition) at the end of compression. As used in many RCMs [23][24][25][26][27][28][29], a creviced piston is used to suppress boundary vortex caused by the movement of the piston and to maintain well-defined homogeneous conditions in the reactor cylinder. As a result, the "adiabatic core" hypothesis can be used more accurately, and the compressed temperature can be calculated using the following equation:…”

Section: Rapid Compression Machinementioning

confidence: 99%

Effects of Buffer Gas Composition on Autoignition of Dimethyl Ether

et al. 2015

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Abstract:Experimental and numerical studies are conducted on the thermal, chemical and dilution effects of buffer gas composition on autoignition of dimethyl ether (DME). The buffer gases considered are nitrogen (N2), a mixture of N2 and argon (Ar) at a mole ratio of 50%/50% and a mixture of Ar and carbon dioxide (CO2) at a mole ratio of 61.2%/38.8%. Experiments are performed using a rapid compression machine (RCM) at compressed pressure of 10 bar, equivalence ratio (φ) of 1, and compressed temperature from 670 K to 795 K. The N2 dilution ratio considered ranges from 36.31% to 55.04%. The experimental results show that buffer gas composition has little impact on the first-stage ignition delay. However, significant differences in the total ignition delay as a function of buffer gas composition are observed in the negative temperature coefficient (NTC) region. Compared to N2, N2/Ar (50%/50%) mixture decreases the total ignition delay by 31%. The chemical effects of buffer gas composition on the first-stage and total ignition delays are negligible. With increasing N2 dilution ratio, the first-stage ignition delay slightly increases, while a significant increase in the total ignition delay is observed. Moreover, the NTC behavior of total ignition delay is noted to become more pronounced at high N2 dilution ratio. The heat release during the first-stage ignition decreases as N2 dilution ratio increases. Results of OPEN ACCESSEnergies 2015, 8 10199 numerical simulations with the Zhao DME mechanism over a wider range of temperature show good agreement with that of experiments. Further numerical simulations are conducted using pure N2, Ar and CO2 as buffer gases. Results indicate that the thermal effects are the dominant factor in low temperature and NTC regions. The chemical effects become pronounced in the NTC region, and the chemical effect of CO2 exceeds the thermal effect at the compressed temperature higher than 880 K.

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Section: Rapid Compression Machinementioning

confidence: 99%

Effects of Buffer Gas Composition on Autoignition of Dimethyl Ether

et al. 2015

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“…Yasunaga et al [37,38] presented a DEE chemical kinetic model for high temperature pyrolysis and oxidation conditions. Werler et al [39] later validated the model against high temperature shock tube measurements and made modifications to rates of hydrogen abstraction by HO 2 radicals to better predict their data. The aforementioned experimental studies on DEE focused primarily on high temperature conditions (i.e., above 1000 K).…”

Section: Chemical Kineticsmentioning

confidence: 99%

“…The DEE model was not validated under lower temperature conditions of relevance to CI engine ignition. Therefore, we started with the high temperature kinetic model from Yasunaga et al [37,38] with the modifications suggested by Werler et al [39]. The low temperature reaction classes and related rate constants were added by analogy to the comprehensive di-butyl ether (DBE) kinetic model developed by Cai et al [40].…”

Section: Chemical Kineticsmentioning

confidence: 99%

Experimental and Numerical Investigation of Ethanol/Diethyl Ether Mixtures in a CI Engine

Vedharaj¹,

Vallinayagam²,

Ali³

et al. 2016

SAE Technical Paper Series

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The auto-ignition characteristics of diethyl ether (DEE)/ethanol mixtures are investigated in compression ignition (CI) engines both numerically and experimentally. While DEE has a higher derived cetane number (DCN) of 139, ethanol exhibits poor ignition characteristics with a DCN of 8. DEE was used as an ignition promoter for the operation of ethanol in a CI engine. Mixtures of DEE and ethanol (DE), i.e., DE75 (75% DEE + 25% ethanol), DE50 (50% DEE + 50% ethanol) and DE25 (25% DEE + 75% ethanol), were tested in a CI engine. While DE75 and DE50 auto-ignited at an inlet air pressure of 1.5 bar, DE25 failed to auto-ignite even at boosted pressure of 2 bar. The peak in-cylinder pressure for diesel and DE75 were comparable, while DE50 showed reduced peak in-cylinder pressure with delayed start of combustion (SOC). Numerical simulations were conducted to study the engine combustion characteristics of DE mixture. A comprehensive detailed chemical kinetic model was created to represent the combustion of DE mixtures. The detailed mechanism was then reduced using standard direct relation graph (DRG-X) method and coupled with 3D CFD code, CONVERGE, to simulate the experimental data. The simulation results showed that the effects of physical properties on DE50 combustion are negligible. Simulations of DE50 mixture revealed that the combustion is nearly homogenous, while diesel (n-heptane used as a surrogate) and DE75 showed similar combustion behavior with flame liftoff and diffusion controlled combustion. Diesel exhibited auto-ignition at an equivalence ratio of 2, while DE75 and DE50 showed auto-ignition in the equivalence ratio range of 1-1.5 and 0-1, respectively. The experiments and numerical simulations demonstrate how the high reactivity of DEE supports the auto-ignition of ethanol, while ethanol acts as a radical scavenger.

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“…The principle advantage is that detailed numerical modeling can be applied, thereby allowing a rigorous test of the combustion kinetics. For example, configurations have included shock tubes and rapid compression machines (Gauthier et al 2004;Yahyaoui et al 2007;Werler et al 2014), counter flow flames and jet-stirred reactors (Choi et al 2011;Dagaut et al 2008), and premixed and non-premixed flow reactors (Chaos et al 2007;Bieleveld et al 2009), among others. They require that the fuel be pre-vaporized before entering the combustion zone.…”

Section: The Canonical Configuration For Liquid Fuel Combustionmentioning

confidence: 99%

“…4a is its one-dimensional gas transport that facilitates developing a numerical simulation of the burning process that can include detailed combustion chemistry, unsteady effects, and spectral radiative sub-models. Armed with this capability, it is possible to use measured combustion properties to evaluate some of the numerical inputs required for predictions [e.g., modifying the combustion chemistry to provide a better match between predicted and measured combustion properties (e.g., Werler et al 2014)]. To illustrate the sort of comparative process that lies at the heart of using a detailed numerical simulation to predict combustion properties for the spherically symmetric droplet flame configuration, we consider methyl decanoate (MD) droplets burning under conditions that promote spherical droplet flames.…”

Section: Combustion Properties Of the Spherical Droplet Flame Configumentioning

confidence: 99%

Developing Surrogates for Liquid Transportation Fuels: The Role of Spherically Symmetric Droplet Combustion

Avedisian

2014

Novel Combustion Concepts for Sustainable Energy Development

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The finite supply of transportation fuels has generated renewed interest to improve their performance in power and propulsion devices. However, the complexity of real fuels prohibits developing their combustion chemistries and property databases needed for simulating performance in engines to identify operational regimes for improving fuel efficiency. Surrogates offer the means to address these concerns if they can be shown to replicate certain combustion targets of the real fuel, and to result in combustion properties similar to real fuels when burned in a suitable configuration that is amenable to detailed numerical modeling. This paper examines the role which droplet combustion can play in the development of surrogates for complex transportation fuels. Recognizing that spray combustion is far too difficult to model and that droplets represent the fine-grid structure of sprays, the combustion dynamics of fuel droplets are examined in an environment that seeks to remove external convective influences to simplify the transport field and produce spherical symmetry in the droplet burning process that can be modeled using a detailed numerical simulation approach. The one-dimensional flames and transport dynamics that result are shown to be well positioned to evaluate the efficacy of surrogate fuel performance. Recent efforts are summarized that have used the spherical droplet flame configuration to evaluate the performance of surrogate fuel blends. Experiments are discussed for promoting spherical symmetry, and results are presented to show the efficacy of some surrogate blends to replicate the performance of gasoline and jet fuels using the spherical droplet configuration. Some results are also included from detailed numerical modeling of biodiesel droplets that incorporate complex combustion chemistry, and unsteady transport, vaporization, and variable property effects that illustrate the potential for high fidelity predictions needed for developing surrogates using the spherically symmetric droplet flame configuration.

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Ignition delay times of diethyl ether measured in a high-pressure shock tube and a rapid compression machine

Cited by 77 publications

References 23 publications

Effects of Buffer Gas Composition on Autoignition of Dimethyl Ether

Effects of Buffer Gas Composition on Autoignition of Dimethyl Ether

Experimental and Numerical Investigation of Ethanol/Diethyl Ether Mixtures in a CI Engine

Developing Surrogates for Liquid Transportation Fuels: The Role of Spherically Symmetric Droplet Combustion

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