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Title: Auto-ignitive deflagration speed of methane (CH4) blended dimethyl-ether (DME)/air mixtures at stratified conditions

Abstract

Front propagation speeds from fully resolved unsteady one dimensional simulations with dimethyl-ether (DME)/methane (CH4)/air mixtures under engine relevant conditions are presented using complex kinetics and transport. Different time-scales of monochromatic inhomogeneities in DME concentration with varying DME/CH4 blending ratios are simulated to unravel the fundamental aspects of auto-ignition and flame propagation under the influence of reactivity stratification. To understand the influence of different stratification time-scales on the flame-ignition interaction, two sets of conditions are simulated such that low temperature chemistry is present in only one of them. For a given amplitude of stratification, it is found that the instantaneous propagation speed is significantly affected by the level of CH4 concentration in the binary fuel blend. Specifically, for cases with low temperature chemistry, at relatively smaller time-scales, the overall fluctuation in the instantaneous propagation speed is found to subside as the level of CH4 concentration in the mixture is increased. However, for both sets of conditions, at comparatively larger time-scales, a rapid change in the instantaneous propagation speed is observed with an increase in the level of CH4 concentration in the mixture. The intrinsic effects of stratification time-scales on the low temperature chemistry and the high temperature chemistry are further examinedmore » to assess the flame-ignition interaction. A displacement speed analysis is also carried out to elucidate the underlying combustion modes that are responsible for such a variation in flame response.« less

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]
  1. Univ. of Tennessee, Knoxville, TN (United States)
  2. Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia). Clean Combustion Research Center
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1615991
Alternate Identifier(s):
OSTI ID: 1775660
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Combustion and Flame
Additional Journal Information:
Journal Volume: 211; Journal Issue: C; Journal ID: ISSN 0010-2180
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Desai, Swapnil, Sankaran, Ramanan, and Im, Hong G. Auto-ignitive deflagration speed of methane (CH4) blended dimethyl-ether (DME)/air mixtures at stratified conditions. United States: N. p., 2019. Web. doi:10.1016/j.combustflame.2019.10.001.
Desai, Swapnil, Sankaran, Ramanan, & Im, Hong G. Auto-ignitive deflagration speed of methane (CH4) blended dimethyl-ether (DME)/air mixtures at stratified conditions. United States. https://doi.org/10.1016/j.combustflame.2019.10.001
Desai, Swapnil, Sankaran, Ramanan, and Im, Hong G. Thu . "Auto-ignitive deflagration speed of methane (CH4) blended dimethyl-ether (DME)/air mixtures at stratified conditions". United States. https://doi.org/10.1016/j.combustflame.2019.10.001. https://www.osti.gov/servlets/purl/1615991.
@article{osti_1615991,
title = {Auto-ignitive deflagration speed of methane (CH4) blended dimethyl-ether (DME)/air mixtures at stratified conditions},
author = {Desai, Swapnil and Sankaran, Ramanan and Im, Hong G.},
abstractNote = {Front propagation speeds from fully resolved unsteady one dimensional simulations with dimethyl-ether (DME)/methane (CH4)/air mixtures under engine relevant conditions are presented using complex kinetics and transport. Different time-scales of monochromatic inhomogeneities in DME concentration with varying DME/CH4 blending ratios are simulated to unravel the fundamental aspects of auto-ignition and flame propagation under the influence of reactivity stratification. To understand the influence of different stratification time-scales on the flame-ignition interaction, two sets of conditions are simulated such that low temperature chemistry is present in only one of them. For a given amplitude of stratification, it is found that the instantaneous propagation speed is significantly affected by the level of CH4 concentration in the binary fuel blend. Specifically, for cases with low temperature chemistry, at relatively smaller time-scales, the overall fluctuation in the instantaneous propagation speed is found to subside as the level of CH4 concentration in the mixture is increased. However, for both sets of conditions, at comparatively larger time-scales, a rapid change in the instantaneous propagation speed is observed with an increase in the level of CH4 concentration in the mixture. The intrinsic effects of stratification time-scales on the low temperature chemistry and the high temperature chemistry are further examined to assess the flame-ignition interaction. A displacement speed analysis is also carried out to elucidate the underlying combustion modes that are responsible for such a variation in flame response.},
doi = {10.1016/j.combustflame.2019.10.001},
journal = {Combustion and Flame},
number = C,
volume = 211,
place = {United States},
year = {2019},
month = {10}
}

Journal Article:

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Cited by: 9 works
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Figures / Tables:

Table 1 Table 1: Physical and numerical parameters used in LTC and HTC cases

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