Gas-particle flow in vertical pipes with high mass loading of particles

Dasgupta, Sanjay; Jackson, R.; Sundaresan, Sankaran

doi:10.1016/s0032-5910(97)03348-2

Cited by 39 publications

(30 citation statements)

References 14 publications

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“…the Navier-Stokes equation). Instead, they are most often derived by analogy with classical single-phase turbulence models (see, e.g., Sinclair & Jackson 1989;Dasgupta, Jackson & Sundaresan 1994;Cao & Ahmadi 1995;Dasgupta, Jackson & Sundaresan 1998;Cheng et al 1999;Jiang & Zhang 2012;Rao et al 2012;Zeng & Zhou 2006). Thus, unlike in single-phase flows where direct numerical simulations (DNS) can be used to evaluate turbulence closures (e.g.…”

Section: Introductionmentioning

confidence: 99%

On multiphase turbulence models for collisional fluid–particle flows

Fox¹

2014

J. Fluid Mech.

187

215

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Starting from a kinetic theory (KT) model for monodisperse granular flow, the exact Reynolds-averaged (RA) equations are derived for the particle phase in a collisional fluid-particle flow. The corresponding equations for a constant-density fluid phase are derived from a model that includes drag and buoyancy coupling with the particle phase. The fully coupled macroscale/hydrodynamic model, rigorously derived from a kinetic equation for the particles, is written in terms of the particle-phase volume fraction, the particle-phase velocity and the granular temperature (or total granular energy). As derived from the hydrodynamic model, the RA turbulence model solves for the RA particle-phase volume fraction, the phase-averaged (PA) particle-phase velocity, the PA granular temperature and the PA turbulent kinetic energy of the particle phase. Thus, unlike in most previous derivations of macroscale turbulence models for moderately dense granular flows, a clear distinction is made between the PA granular temperature Θ p , which appears in the KT constitutive relations, and the particle-phase turbulent kinetic energy k p , which appears in the turbulent transport coefficients. The exact RA equations contain unclosed terms due to nonlinearities in the hydrodynamic model and we briefly discuss the available closures for these terms. Finally, we demonstrate by comparing model predictions with direct numerical simulation results that even for non-collisional fluid-particle flows it is necessary to provide separate models for Θ p and k p in order to correctly account for the effect of the particle Stokes number and mass loading.

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Section: Introductionmentioning

confidence: 99%

On multiphase turbulence models for collisional fluid–particle flows

Fox¹

2014

J. Fluid Mech.

187

215

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“…This is the case, for instance, when the interfacial morphology is fixed or changes slowly as in heat exchangers with a melting front (Sasaguchi, Kusano & Viskanta 1997). Another example is a fluidized-bed reactor having millions of fine particles, where it is impractical and perhaps unnecessary to resolve the details on the particle length-scale (Dasgupta, Jackson & Sundaresan 1998). In general, however, heat and mass transfer and reaction rate are strong functions of the phase morphology, which, in turn, is dictated by the interaction among individual particles (Joseph 1996;Tirumkudulu, Tripathi & Acrivos 1999).…”

Section: Introductionmentioning

confidence: 99%

Direct numerical simulation of the sedimentation of solid particles with thermal convection

et al. 2003

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Dispersed two-phase flows often involve interfacial activities such as chemical reaction and phase change, which couple the fluid dynamics with heat and mass transfer. As a step toward understanding such problems, we numerically simulate the sedimentation of solid bodies in a Newtonian fluid with convection heat transfer. The two-dimensional Navier-Stokes and energy equations are solved at moderate Reynolds numbers by a finite-element method, and the motion of solid particles is tracked using an arbitrary Lagrangian-Eulerian scheme. Results show that thermal convection may fundamentally change the way that particles move and interact. For a single particle settling in a channel, various Grashof-number regimes are identified, where the particle may settle straight down or migrate toward a wall or oscillate laterally. A pair of particles tend to separate if they are colder than the fluid and aggregate if they are hotter. These effects are analysed in terms of the competition between the thermal convection and the external flow relative to the particle. The mechanisms thus revealed have interesting implications for the formation of microstructures in interfacially active two-phase flows. Dispersed two-phase flows often involve interfacial activities such as chemical reaction and phase change, which couple the fluid dynamics with heat and mass transfer. As a step toward understanding such problems, we numerically simulate the sedimentation of solid bodies in a Newtonian fluid with convection heat transfer. The twodimensional Navier-Stokes and energy equations are solved at moderate Reynolds numbers by a finite-element method, and the motion of solid particles is tracked using an arbitrary Lagrangian-Eulerian scheme. Results show that thermal convection may fundamentally change the way that particles move and interact. For a single particle settling in a channel, various Grashof-number regimes are identified, where the particle may settle straight down or migrate toward a wall or oscillate laterally. A pair of particles tend to separate if they are colder than the fluid and aggregate if they are hotter. These effects are analysed in terms of the competition between the thermal convection and the external flow relative to the particle. The mechanisms thus revealed have interesting implications for the formation of microstructures in interfacially active two-phase flows. Disciplines Engineering | Mechanical Engineering

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“…Owing to their inherent complexity and scale of flow domain, the standard k-turbulent model has been 10 used (Dasgupta et al, 1998;Almuttahar and Taghipour, 2008;and Shah et al, 2011b) for the turbulent 11 properties. There are three different types of formulations that are possible for the standard k turbulent 12 model.…”

Section: Gas Phase Stressesmentioning

confidence: 99%

“…These equations are formulated for a single pseudo phase made of the mixture of the 14 gas and solids phases. This model then uses mixture properties to calculate the turbulence properties 15 (Dasgupta et al, 1998). The conservation equation for the kinetic energy and dissipation rate can be written 16 as: M a n u s c r i p t eq.…”

Section: Gas Phase Stressesmentioning

confidence: 99%