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Title: Numerical and experimental investigation of turbulent DME jet flames

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Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
Grant/Contract Number:
SC0001198; SC0008622
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Proceedings of the Combustion Institute
Additional Journal Information:
Journal Volume: 35; Journal Issue: 2; Related Information: CHORUS Timestamp: 2017-05-17 09:41:05; Journal ID: ISSN 1540-7489
Country of Publication:
United States

Citation Formats

Bhagatwala, Ankit, Luo, Zhaoyu, Shen, Han, Sutton, Jeffrey A., Lu, Tianfeng, and Chen, Jacqueline H.. Numerical and experimental investigation of turbulent DME jet flames. United States: N. p., 2015. Web. doi:10.1016/j.proci.2014.05.147.
Bhagatwala, Ankit, Luo, Zhaoyu, Shen, Han, Sutton, Jeffrey A., Lu, Tianfeng, & Chen, Jacqueline H.. Numerical and experimental investigation of turbulent DME jet flames. United States. doi:10.1016/j.proci.2014.05.147.
Bhagatwala, Ankit, Luo, Zhaoyu, Shen, Han, Sutton, Jeffrey A., Lu, Tianfeng, and Chen, Jacqueline H.. 2015. "Numerical and experimental investigation of turbulent DME jet flames". United States. doi:10.1016/j.proci.2014.05.147.
title = {Numerical and experimental investigation of turbulent DME jet flames},
author = {Bhagatwala, Ankit and Luo, Zhaoyu and Shen, Han and Sutton, Jeffrey A. and Lu, Tianfeng and Chen, Jacqueline H.},
abstractNote = {},
doi = {10.1016/j.proci.2014.05.147},
journal = {Proceedings of the Combustion Institute},
number = 2,
volume = 35,
place = {United States},
year = 2015,
month = 1

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.proci.2014.05.147

Citation Metrics:
Cited by: 25works
Citation information provided by
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  • Cited by 1
  • The present paper is devoted to (i) the experimental study of partially premixed combustion with strong equivalence ratio gradients, i.e., stratification of the reactive mixture and (ii) the numerical modeling of turbulent reactive flows in such situations where reactants are far from being ideally premixed. From a practical point of view, at least two variables are necessary to describe the local thermochemistry in this case: the mixture fraction {xi} and the fuel mass fraction Y{sub f} are considered to represent respectively the local composition of the fresh mixture and the progress of chemical reactions. From the experimental point of view,more » the use of simultaneous imaging techniques allows the evaluation of both variables in terms of fuel mole fraction and temperature. In the present study, a combined acetone PLIF measurement and Rayleigh scattering technique is used. The influence of temperature on the fluorescence signal is corrected thanks to the knowledge of the local temperature through Rayleigh scattering measurements. Conversely, the influence of the acetone Rayleigh cross section can be evaluated with the local value of acetone mole fraction. Using the iterative procedure already described by Degardin et al. [Exp. Fluids 40 (2006) 452-463], the corrected fuel mole fraction and temperature fields can be obtained. Here the particular flow configuration under study is a stratified turbulent V-shaped flame of methane and air. In a first step of the analysis, the optical diagnostics are used to perform a detailed investigation of the flame thickness with a special emphasis on the influence of partially premixed conditions. In a second step, experimental data are used to evaluate the LW-P model as defined by Robin et al. [Combust. Sci. Technol. 178 (10-11) (2006) 1843-1870] to calculate turbulent reactive flows with partially premixed conditions based on an earlier analysis by Libby and Williams [Combust. Sci. Technol. 161 (2000) 351-390]. The closure problem raised by the mean scalar dissipation terms is also discussed in the light of experimental results. Since the usual closures for nonreactive flows are expected to be unsuitable to describe reactive scalar fluctuations decay a new modeling proposal based on the recent developments of Mura et al. [Combust. Flame 149 (2007) 217-224] is used. After a preliminary validation step where numerical predictions of the flame mean quantities are compared successfully with the experimental database, numerical simulations are used to describe the mean structure of stratified flames and in particular the evolution of the mean chemical reaction rate for different partially premixed conditions. (author)« less
  • This paper describes an experimental investigation of acoustically forced lean premixed turbulent bluff-body-stabilised flames in an enclosure short enough so that no coupling of the combustor downstream acoustics occurred for the frequencies studied here, which allows an unambiguous examination of the flame response to inlet velocity fluctuations. Special emphasis was placed on the amplitude dependence of this response. Measurements of the heat release rate were performed with OH{sup *} and CH{sup *} chemiluminescence, planar laser-induced fluorescence (PLIF) of OH from which the flame surface density (FSD) was computed, and simultaneous CH{sub 2}O and OH PLIF imaging from which the localmore » heat release rate (RX) was estimated. The global heat release measured with chemiluminescence and that integrated from the local FSD measurements were in close agreement, while a comparison between FSD and high-resolution RX imaging also showed good agreement. This suggests that estimates of the flame area are sufficient to determine heat release rate for this flow. The heat release response became nonlinear after inlet velocity amplitudes of around 15% of the bulk velocity. This value depended on the forcing frequency and the equivalence ratio. The nonlinearity was found to occur when the shear layers rolled up into vortices. The vortices induced by the inlet velocity fluctuations not only generated flame area when the flame wrapped around them, but also caused cusps and even large-scale flame annihilation events, as observed in time-resolved OH PLIF images. Such events occurred when parts of the flame stabilised on the inner shear layer close to the recirculation zone collapsed on parts of the flame stabilised on the outer recirculation zone, a phenomenon that was made more prominent with increasing forcing amplitude. A further nonlinearity occurred at high amplitudes and at some equivalence ratios, where a significant leakage of energy to higher harmonics was observed, but the origin of this is not yet clarified. The present results suggest that the flame sheet kinematics play a major role in the saturation mechanism of lean premixed flame response, hence extending previous experimental and analytical results from laminar to turbulent flames. Heat release fluctuations due to local fluctuations of strain rate and curvature were less significant, while no localised extinction has been observed even at large forcing amplitudes.« less