Large-eddy simulation of a dispersed particle-laden turbulent round jet Thomas G. Almeida * , Farhad A. Jaberi Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan 48824-1226, USA Received 13 October 2006; received in revised form 24 April 2007 Available online 28 June 2007 Abstract The numerical results obtained by large-eddy simulation (LES) of a particle-laden axisymmetric turbulent jet are compared with the available experimental data. The results indicate that with a new stochastic subgrid-scale (SGS) closure, the effects of the particles on the carrier gas and those of the carrier gas on the particles are correctly captured by the LES. Additional numerical experiments are con- ducted and used to investigate the effects of particle size, mass-loading ratio, and other flow/particle parameters on the statistics of both the carrier gas phase and the particle dispersed phase. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Particle-laden jet; Dilute, two-phase flows; Turbulent jet; LES 1. Introduction Among various predictive methods available for parti- cle-laden or droplet-laden dispersed multiphase turbulent flows, the numerical methods based on large eddy simula- tion (LES) are very attractive as they provide the most optimum means of capturing the unsteady physical fea- tures in these flows [1–6]. The accuracy and the reliability of LES predictions is, however, dependent on several fac- tors such as the accurate modeling of the subgrid-scale (SGS) phase interactions and the correct representation of the initial/boundary conditions for all phases. To ensure the accuracy of a given model, both verification and valida- tion studies should be conducted as suggested by Boivin et al. [7]. Of high importance to the development and ver- ification of LES SGS models are both a priori analysis of direct numerical simulation (DNS) data, and a posteriori analysis of LES results via comparison with the laboratory experiments. Armenio et al. [8] investigated the effects of the SGS on particle motion. Their work indicates that using a filtered velocity field alone to advance the particles can lead to seri- ous inaccuracies; thus the importance of the SGS closures is emphasized. Miller and Bellan [9] conducted a thorough a priori analysis of the SGS effects using DNS results for a transitional mixing layer, and they also concluded that neglecting the SGS velocity fluctuations in LES might lead to gross errors in the prediction of the particle drag force. This, in turn, will lead to errors in both the carrier-phase and the dispersed-phase. Miller [10] went on to investigate the effects of solid particles on an exothermic reacting mix- ing layer. He found that the preferential concentration of the particles in the high-strain braid regions of the mixing layer, can lead to local flame extinction. Several other researchers have also used DNS data for a better under- standing of isothermal and non-isothermal reacting and nonreacting particle-laden turbulent flows. For example, Mashayek [11,12] and Mashayek and Jaberi [13] noted that the presence of particles effectively decreases the turbulent kinetic energy while increasing the anisotropy of homoge- neous turbulent shear flows. These effects were shown to be magnified by increasing either the mass-loading ratio or the particle time constant. They also found that the autocorrelation coefficient of the velocity of the carrier 0017-9310/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.ijheatmasstransfer.2007.04.023 * Corresponding author. Present address: General Dynamics-AIS, 1200 Joe Hall Drive, Ypsilanti, MI 48197, USA. Tel.: +1 734 480 5021; fax: +1 734 480 5367. E-mail address: thomas.almeida@gd-ais.com (T.G. Almeida). www.elsevier.com/locate/ijhmt Available online at www.sciencedirect.com International Journal of Heat and Mass Transfer 51 (2008) 683–695