A Numerical Model of Dispersed Two Phase Flow in Aerated Stirred Vessels based on Presumed Shape Number Density Functions

Gharaibah, Emad; Polifke, Wolfgang

doi:10.1007/978-3-642-18540-3_23

Cited by 2 publications

(3 citation statements)

References 1 publication

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“…The model validity was examined based on previous experiments and reference data. The hydrodynamic modelling of gas-liquid flow has been validated previously (Gharaibah & Polifke, 2004). The kinetic model has been checked against experimental data in the kinetic study (Znad, Blazej, et al, 2004).…”

Section: Numerical Procedures and Solution Strategymentioning

confidence: 99%

CFD modelling of two-phase stirred bioreaction systems by segregated solution of the Euler–Euler model

Elqotbi

Vlaev

Montastruc

et al. 2013

Computers & Chemical Engineering

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An advanced study of a bioreactor system involving a Navier-Stokes based model has been accomplished. The model allows a more realistic impeller induced flow image to be combined with the Monod bioreaction kinetics reported previously. The time-course of gluconic acid production by Aspergillus niger strain is simulated at kinetic conditions proposed in the literature. The simulation is based on (1) a stepwise solution strategy resolving first the fluid flow field, further imposing oxygen mass transfer and bioreaction with subsequent analysis of flow interactions, and (2) a segregated solution of the model replacing the multiple iterations per grid cell with single iterations. The numerical results are compared with experimental data for the bioreaction dynamics and show satisfactory agreement. The model is used for assessment of the viscosity effect upon the bioreactor performance. A 10-fold viscosity rise results in 2-fold decrease of K L a and 25% decrease of the specific gluconic acid production rate. The model allows better understanding of the mechanism of the important bioprocess.

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Section: Numerical Procedures and Solution Strategymentioning

confidence: 99%

CFD modelling of two-phase stirred bioreaction systems by segregated solution of the Euler–Euler model

Elqotbi

Vlaev

Montastruc

et al. 2013

Computers & Chemical Engineering

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“…The MUSIG (MUltiple-SIze-Group) model [46,47] was originally developed for the prediction of bubbles in water and has never been used for the prediction of mixing and evaporation of liquid droplets in a stream of gas. It is the intention of this work to extend the applicability of MUSIG to such configuration.…”

Section: The Multi-size-group Model (Musig)mentioning

confidence: 99%

“…. The break-up frequency of a mother particle with size d j splitting into two particles of sizes d i and is obtained as (46) where F B is added as a calibration factor of the model, ε c is the continuous phase eddy dissipation energy, σ is the surface tension, β=2, and ξ is the dimensionless size of eddies in the inertial subrange of isotropic turbulence. The lower limit of the integration is given by (47) and the Kolmogorov micro-scale η is given by:…”

Section: Luo and Svendsen Breakup Modelmentioning

confidence: 99%

Mixing and evaporation of liquid droplets injected into an air stream flowing at all speeds

Moukalled

Darwish

2008

Physics of Fluids

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This paper deals with the formulation, implementation, and testing of three numerical techniques based on (i) a full multiphase approach, (ii) a MUlti-SIze Group (MUSIG) approach, and (iii) a Heterogeneous MUSIG (H-MUSIG) approach for the prediction of mixing and evaporation of liquid droplets injected into a stream of air. The numerical procedures are formulated following an Eulerian approach, within a pressure-based fully conservative Finite Volume method equally applicable in the subsonic, transonic, and supersonic regimes, for the discrete and continuous phases. The k-ε two-equation turbulence model is used to account for the droplet and gas turbulence with modifications to account for compressibility at high speeds. The performances of the various methods are compared by solving for two configurations involving stream-wise and cross-stream spraying into subsonic and supersonic streams. Results, displayed in the form of droplet velocity vectors, contour plots, and axial profiles indicate that solutions obtained by the various techniques exhibit similar behavior. Differences in values are relatively small with the largest being associated with droplet volume fractions and vapor mass fraction in the gas phase. This is attributed to the fact that with MUSIG and H-MUSIG no droplet diameter equation is solved and the diameter of the various droplet phases are held constant, as opposed to the full multiphase approach.

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A Numerical Model of Dispersed Two Phase Flow in Aerated Stirred Vessels based on Presumed Shape Number Density Functions

Cited by 2 publications

References 1 publication

CFD modelling of two-phase stirred bioreaction systems by segregated solution of the Euler–Euler model

CFD modelling of two-phase stirred bioreaction systems by segregated solution of the Euler–Euler model

Mixing and evaporation of liquid droplets injected into an air stream flowing at all speeds

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