Turbulence models and their applications to the prediction of internal flows: A review

Nallasamy, M.

doi:10.1016/s0045-7930(87)80003-8

Cited by 207 publications

(91 citation statements)

References 81 publications

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“…The additional transport equations requiring for calculation of the Reynolds stresses are employed to close the above equations [18]. Comparing the closing models of the standard k-ε model, the Reynolds stress model (RSM) calculate the Reynolds stresses from their own transport equations, which may described some anisotropy of turbulence [19]. In this paper, the turbulence model of RSM is used to …”

Section: Governing Equationsmentioning

confidence: 99%

Effect on the Flow Behaviors by Adding Internals in a Riser Reactor

Liu¹,

Bu²,

Wang³

et al. 2017

OJFD

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Riser reactor is a key unit in the Fluid Catalytic Cracking (FCC), and it has important influences on increasing the yield coefficient of gas and oil. In this paper, the behaviors of gas-solid two-phase flow in the traditional y-type riser reactor are investigated by numerical simulation. The calculated particle concentration distribution is in good agreement with the experimental data, which verified the advanced models and calculating methods. The nonuniform distribution, such as core-annulus flow, may result in the unreasonable matching relationship of catalyst-to-oil ratio. An optimized riser with cuneal internals is proposed and the comparison of two different structures of riser reactor is presented. The comparison results show that the cuneal internals in the riser both can block effectively the slip down of the particles near wall region and weaken core-annulus flow structure due to the redistribution of particles. The results also prove that the particle concentration distribution becomes uniform along the axial and radial direction in the optimized riser by adding cuneal internals, which would be benefits for the catalytic cracking reactions.

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Section: Governing Equationsmentioning

confidence: 99%

Effect on the Flow Behaviors by Adding Internals in a Riser Reactor

Liu¹,

Bu²,

Wang³

et al. 2017

OJFD

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“…The turbulent kinetic energy k and dissipation rate ε of the fluid flow at the upstream and downstream boundaries are determined by specifying the turbulent intensity of the fluid flow. In this paper a turbulent intensity of 10% was assumed for both upstream and downstream boundaries (Ma et al [6], Nallasamy [8]). …”

Section: Boundary Conditionsmentioning

confidence: 99%

Validation of a CFD model for flow in meandering rivers using an experimental test-setup: first results

Delecluyse

Brantegem

Troch

et al. 2008

Advances in Fluid Mechanics VII

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A 3D Reynolds Averaged Navier Stokes (RANS) model of a meandering channel with rectangular cross-section has been developed using the commercial software package FLUENT 6.2. This model solves the 3D Navier-Stokes equations using the PISO scheme for the pressure-velocity coupling and the realizable k-ε model for turbulence closure. Output of the numerical model is compared to validation experiments conducted in a physical model, which represents two wavelengths of a regime channel and allows for the measurement of flow patterns at several discharges and variable bed forms. The computed water depths and velocity profiles of the CFD model output are in good agreement with the physical model results. The simulations slightly underpredict the streamwise velocities, which reach a maximum just before the apex of the meander bend, at the inner bank in the lower part of the flow depth. The CFD model also captures the motion of the secondary current or transverse flow well, showing the same direction of current along the entire second wavelength.

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“…The standard k-ε two-equation turbulence model has been widely applied to engineering practice, but has been criticized as being only qualitatively correct in the simulation of confined swirling flows [7,8]. This is because of the neglect of anisotropic viscosity and additional turbulence generation arising from the effects of streamline curvature in the standard k-ε model [7].…”

Section: Introductionmentioning

confidence: 99%

“…Hence, some corrections [8][9][10] concerning the standard k-ε model have to be made in order to simulate confined swirling flow. However, none of such modification was found to work well under all kinds of geometries and for a wide range of swirl number [8][9][10].…”

Section: Introductionmentioning

confidence: 99%