Direct numerical simulations of autoignition in turbulent two-phase flows

Schroll, Peter and Wandel, Andrew P. and Cant, R. Stewart and Mastorakos, E. (2009) Direct numerical simulations of autoignition in turbulent two-phase flows. Proceedings of the Combustion Institute, 32 (2). pp. 2275-2282. ISSN 1540-7489


Three-dimensional direct numerical simulations (DNS) were carried out to investigate the impact of evaporation of droplets on the autoignition process under decaying turbulence. The droplets were taken as point sources and were tracked in a Lagrangian manner. Three cases with the same initial equivalenceratio but different initial droplet size were simulated and the focus was to examine the influence of the droplet evaporation process on the location of autoignition. It was found that an increase in the initial droplet size results in an increase in the autoignition time, that highest reaction rates always occur at a specific mixture fraction xi_MR, as in purely gaseous flows, and that changes in the initial droplet size did not affect the value of xi_MR. The conditional correlation coefficient between scalar dissipation rate and reaction rates was only mildly negative, contrary to the strongly negative values for purely gaseous autoigniting flows, possibly due to the continuous generation of mixture fraction by the droplet evaporation process that randomizes
both the mixture fraction and the scalar dissipation fields.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Awaiting Authors' Accepted Version, which may be deposited in accordance with the copyright policy of the publisher.
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Mechanical and Mechatronic Engineering
Date Deposited: 27 Jun 2010 08:09
Last Modified: 01 Sep 2014 02:55
Uncontrolled Keywords: autoignition; spray; turbulent; DNS; auto-ignition process; autoignition; conditional correlations; decaying turbulences; DNS; droplet evaporations; droplet sizes; equivalence ratios; gaseous flows; Lagrangian; mixture fractions; negative values; point sources; scalar dissipation rates; scalar dissipations; turbulent two-phase flows
Fields of Research : 09 Engineering > 0913 Mechanical Engineering > 091305 Energy Generation, Conversion and Storage Engineering
09 Engineering > 0915 Interdisciplinary Engineering > 091508 Turbulent Flows
09 Engineering > 0915 Interdisciplinary Engineering > 091501 Computational Fluid Dynamics
Socio-Economic Objective: B Economic Development > 85 Energy > 8599 Other Energy > 859999 Energy not elsewhere classified
Identification Number or DOI: 10.1016/j.proci.2008.06.057

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