Turbulent dimethyl ether (DME) jet flames provide a canonical flame geometry for studying turbulence-flame interactions in oxygenated fuels and for developing predictive models of these interactions. The development of accurate models for DME/air flames would establish a foundation for studies of more complex oxygenated fuels. We present a joint experimental and computational investigation of the velocity field and OH and CH2O distributions in a piloted, partially-premixed turbulent DME/air jet flame with a jet exit Reynolds number, ReD, of 29,300. The turbulent DME/air flame is analogous to the well-studied, partially-premixed methane/air jet flame, Sandia Flame D, with identical stoichiometric mixture fraction, ξst = 0.35, and bulk jet exit velocity, Vbulk = 45.9 m/s. Measurements include particle image velocimetry (PIV) and simultaneous CH2O and OH laser-induced fluorescence (LIF) imaging. Simulations are performed using a large eddy simulation combined with conditional moment closure (LES-CMC) on an intermediate size grid of 1.3 million cells. Overall, the downstream evolution of the mean and RMS profiles of velocity, OH, and CH2O are well predicted, with the largest discrepancies occurring for CH2O at x/D = 20-25. LES-CMC simulations employing two different chemical reaction mechanisms (Kaiser et al., 2000  and Zhao et al., 2008 ) show approximately a factor of two difference in the peak CH2O mole fractions, whereas OH mole fractions are in good agreement between the two mechanisms. The single-shot LIF measurements of OH and CH2O show a wide range of separation distances between the spatial distributions of these intermediate species with gaps on the order of millimeters. The intermittency in the overlap between these species indicates that the consumption rates of formaldehyde by OH in the turbulent DME/air jet flame may be highly intermittent with significant departures from flamelet models.
|Number of pages||8|
|Journal||Proceedings of the Combustion Institute|
|Publication status||Published - 2015|
|Event||30th International Symposium on Combustion - Chicago, IL, United States|
Duration: 2004 Jul 25 → 2004 Jul 30
Bibliographical noteFunding Information:
The authors thank M.G. Mungal for contributions to the experiments, W.P. Jones for providing the original CFD routines, and E. Huang for technical assistance in the laboratory. The experimental research was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences . Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the U.S. Department of Energy under contract DE-AC04-94-AL85000. The Stuttgart group acknowledges the financial support of DFG (grant no. KR3648/1-2 ), high-performance computing access to HLRS. S.K. Im and M. Gamba were supported by the Department of Energy under Award Number DE-FC52-08NA28614 .
© 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
- TNF workshop
- Turbulent jet flames
ASJC Scopus subject areas
- Chemical Engineering(all)
- Mechanical Engineering
- Physical and Theoretical Chemistry