A time-dependent Eulerian model of droplet diffusion in turbulent flow. (5th June 2016)

• Record Type: Journal Article
• Authors: Ryan, S.D.; Gerber, A.G.; Holloway, A.G.L.
• Is Part Of: Computers & fluids. Volume 131(2016)
• Page Start: 1
• Page End: 15
• Publication Date: 2016-06-05
• Subjects: Turbulent diffusion model -- Particle dispersion -- Multiphase -- DQMOM -- Aerial spraying -- CFD -- Equilibrium-Eulerian model; Fluid dynamics -- Data processing -- Periodicals; 532.050285
• DOI: 10.1016/j.compfluid.2016.03.001
• Languages: English
• ISSNs: 0045-7930

Abstract

Highlights: A new turbulent diffusion coefficient model is developed. The model is appropriate for, but not limited to, aerial spray modeling. The model accounts for inertial and time-limit effects ignored by existing models. The model is validated against experimental wind tunnel measurements. Abstract: Industrial sprays are common in many operations where liquid application to surfaces is required. Maximization of the spray process efficacy depends on accurate simulation of spray characteristics and surrounding flow conditions. Traditionally, droplet modeling has been performed using a Lagrangian approach which requires tracking a sufficient number of droplets to form statistical estimates of droplet deposition. Alternatively for this study, an Eulerian-based flow and droplet transport model using the Direct Quadrature Method of Moments (DQMOM) is applied to spray modeling and is coupled with the Reynolds Averaged Navier Stokes (RANS) equations and Shear Stress Transport (SST) turbulence model. A new turbulent diffusion model is developed for droplet transport which accounts for inertia and time-limit effects and covers a wide range of operational parameters associated with aerial spraying. The model is based on a full parametric study using Lagrangian particle tracking in a uniform, homogeneous and isotropic turbulent flow field and is subsequently implemented within the Eulerian DQMOM framework and compared to: 1) Lagrangian tracking predictions of a log-normal particle size distribution injected into a homogeneous, isotropic turbulent flow field, and 2) full-scale experimental wind tunnel measurements in the anisotropic, non-homogeneous wake of a hollow cone hydraulic nozzle.