Direct numerical simulation of diluted combustion by evaporating droplets


Xia, J and Luo, K.H (2009) Direct numerical simulation of diluted combustion by evaporating droplets. Proceedings of the Combustion Institute, 32, (2), 2267-2274. (doi:10.1016/j.proci.2008.05.047).

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Description/Abstract

Diluted combustion has been studied using DNS in a three-dimensional temporally developing reacting shear-layer with the oxidizer stream laden with evaporating droplets. The gaseous phase is described in the Eulerian frame while the discrete droplet phase is treated in the Lagrangian frame, with strong two-way coupling between the two phases through mass, momentum and energy exchange. Grid-resolution-independent results have been obtained in cases without and with droplets. A comprehensive parametric study has been conducted by varying the initial Stokes number (St0) and mass loading ratio (MLR0). Detailed field analysis has been conducted to examine the complex nonlinear interactions among droplet dynamics, evaporation, turbulence and combustion, and so on. Effects of evaporating droplets on averaged flow and combustion quantities have also been presented. In particular, the conditional scalar dissipation rate is found to be enhanced by evaporating droplets, which suggests that they can promote micromixing and combustion under certain conditions, in addition to their roles in combustion suppression. The transport equation for the mixture fraction variance has been analyzed, with a focus on the vaporization-related source terms. Such source terms exhibit more complex local variations in the present shear-flow non-premixed flame configuration, compared with the case in the homogeneous decaying turbulence configuration of Réveillon and Vervisch (2000).

Item Type: Article
ISSNs: 1540-7489 (print)
1873-2704 (electronic)
Keywords: multiphase combustion, diluted combustion, evaporating droplets, reacting shear-layer, DNS
Subjects: T Technology > T Technology (General)
Divisions: University Structure - Pre August 2011 > School of Engineering Sciences
ePrint ID: 147349
Date Deposited: 23 Apr 2010 14:26
Last Modified: 28 Mar 2014 15:16
Projects:
Study of Vitiated Turbulent Combustion for Low-Emission High-Efficiency Hybrid Energy Systems
Funded by: EPSRC (EP/E011640/1)
Led by: Kai Hong Luo
1 March 2007 to 28 February 2010
URI: http://eprints.soton.ac.uk/id/eprint/147349

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