Particle image velocimetry investigation of the flow-field of a 3D turbulent annular swirling decaying flow induced by means of a tangential inlet

Pruvost, Jérémy; Legrand, Jack; Legentilhomme, P.; Doubliez, Louis

doi:10.1007/s003480000181

Cited by 36 publications

(31 citation statements)

References 2 publications

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“…For a given operating condition, an average of 200 image acquisitions is required to calculate timeaveraged velocity fields. The image post-treatment is equivalent to the one performed by Pruvost et al (2000). Finally, the radial profiles of axial and tangential components of time-averaged velocity (noted U(r) and W(r) respectively) are obtained at different heights, x, in the downcomer.…”

Section: Particle Image Velocimetrymentioning

confidence: 99%

“…Finally, the radial profiles of axial and tangential components of time-averaged velocity (noted U(r) and W(r) respectively) are obtained at different heights, x, in the downcomer. It is important to precise that, according to the measurement planes, the tangential component of velocity, W, can be only known in the vertical symmetrical plane of the downcomer (Pruvost et al, 2000). In Figure 2a, the locations where they are calculated are represented by black points.…”

Section: Particle Image Velocimetrymentioning

confidence: 99%

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A new photobioreactor for continuous microalgal production in hatcheries based on external‐loop airlift and swirling flow

Loubière

Olivo

Bougaran

et al. 2008

Biotech & Bioengineering

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This study deals with the scale of a new photobioreactor for continuous microalgal production in hatcheries. The combination of the state-of-art with the constraints inherent to hatcheries has turned the design into a closed, artificially illuminated and external-loop airlift configuration based on a succession of elementary modules, each one being composed of two transparent vertical interconnected columns. The liquid circulation is ensured pneumatically (air injections) with respect to a swirling motion (tangential inlets). A single module of the whole photobioreactor was built-up to scale its geometry (diameter and length) and to optimize its design (air sparger, tangential inlets). The volumetric productivities were predicted by modeling radiative transfer and growth of Isochrysis affinis galbana (clone Tahiti). The hydrodynamics of the liquid phase was modeled in terms of global flow behavior (circulation and mixing times, Péclet number) and of swirling motion decay along the column (Particle Image Velocimetry). The aeration performances were determined by overall volumetric mass transfer measurements. Continuous cultures of Isochrysis affinis galbana (clone Tahiti) were run in two geometrical configurations, generating either an axial or a swirling flow. Lastly, the definitive options of design are presented as well as a 120-L prototype, currently implemented in a French mollusk hatchery and commercialized.

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Section: Particle Image Velocimetrymentioning

confidence: 99%

Section: Particle Image Velocimetrymentioning

confidence: 99%

A new photobioreactor for continuous microalgal production in hatcheries based on external‐loop airlift and swirling flow

Loubière

Olivo

Bougaran

et al. 2008

Biotech & Bioengineering

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“…In order to validate the CFD model at higher rotational velocities, PIV experiments were performed on a prototype CSAF unit. PIV is a powerful non-intrusive technique to obtain fluid velocities and has been used extensively as a stand-alone method for fluid flow studies (Hill et al, 2000;Hopkins et al, 2000;Pruvost et al, 2000;Shafiqul Islam et al, 2002;Xiong et al, 2003) as well as in conjunction with CFD models (Armenante et al, 1997;Khopkar et al, 2003;Ranade, 1997). These studies include using CFD and PIV to investigate hydrodynamics in bioreactors (Haut et al, 2003;Vial et al, 2002), highlighting the potential use of CFD in modeling and optimizing bioprocessing equipment.…”

Section: Validation Of Cfd Simulationsmentioning

confidence: 96%

Optimizing the rotor design for controlled-shear affinity filtration using computational fluid dynamics

Francis¹,

Martinez²,

Taghipour³

et al. 2006

Biotechnol. Bioeng.

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Controlled shear affinity filtration (CSAF) is a novel integrated processing technology that positions a rotor directly above an affinity membrane chromatography column to permit protein capture and purification directly from cell culture. The conical rotor is intended to provide a uniform and tunable shear stress at the membrane surface that inhibits membrane fouling and cell cake formation by providing a hydrodynamic force away from and a drag force parallel to the membrane surface. Computational fluid dynamics (CFD) simulations are used to show that the rotor in the original CSAF device (Vogel et al., 2002) does not provide uniform shear stress at the membrane surface. This results in the need to operate the system at unnecessarily high rotor speeds to reach a required shear stress of at least 0.17 Pa at every radial position of the membrane surface, compromising the scale-up of the technology. Results from CFD simulations are compared with particle image velocimetry (PIV) experiments and a numerical solution for low Reynolds number conditions to confirm that our CFD model accurately describes the hydrodynamics in the rotor chamber of the CSAF device over a range of rotor velocities, filtrate fluxes, and (both laminar and turbulent) retentate flows. CFD simulations were then carried out in combination with a root-finding method to optimize the shape of the CSAF rotor. The optimized rotor geometry produces a nearly constant shear stress of 0.17 Pa at a rotational velocity of 250 rpm, 60% lower than the original CSAF design. This permits the optimized CSAF device to be scaled up to a maximum rotor diameter 2.5 times larger than is permissible in the original device, thereby providing more than a sixfold increase in volumetric throughput.

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“…Swirling flows generated by tangential inlets in an annular cavity separating two static cylinders would appear to be of special interest, as they require no particular rotation equipment and create no additional pressure drop or contact surface, contrary to the effects produced by turbulence-and vortex-generating baffles and inserts. Moreover, previous studies of this flow pattern Lefèbvre et al, 1998;Legentilhomme and Legrand, 1991;Legentilhomme et al, 1993;Pruvost et al, 1999Pruvost et al, , 2000 have provided a solid basis for further investigation.…”

Section: Introductionmentioning

confidence: 94%

Swirling flow implementation in a photobioreactor for batch and continuous cultures of porphyridium cruentum

Muller‐Feuga

Pruvost

Guédes

et al. 2003

Biotech & Bioengineering

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Light is the main limiting factor in photoautotrophic-intensive production of microorganisms, and improvement of its use is an important concern for photobioreactor design and operation. Swirling flows, which are known to improve mass and photon transfers, were applied to annular light chambers of a photobioreactor and studied by simulation and microalgal culture. Two hydrodynamic conditions were compared: axial flow generating poor radial mixing, and tangential flow generating three-dimensional swirling motion. Batch and continuous cultures of the Rhodophyte Porphyridium cruentum were performed in a 100-L, 1.5-m(2), fully controlled photobioreactor with eight light chambers. The inlet design of these chambers was modified to create the hydrodynamic conditions for comparison. Various intensities of swirling motion were used, characterized by the velocity factor (VF), defined as the ratio between annular chamber flow and inlet aperture sections. Experiments were performed within the range of photon flux densities (PFD) optimizing the yield of light energy transformation into living substance for the species and the temperature used. Culture kinetics with swirling flows generated by apertures of VF = 2, 4, and 9 were compared with pseudoaxial VF = 2 chosen as reference. Batch cultures with VF = 4 swirling flow showed no significant difference, whereas continuous cultures proved more discriminating. Although no significant difference was obtained for VF = 2, a 7% increase of steady-state productivity and a 26% decrease in time required to reach this steady state were obtained with VF = 4 swirling flow. This beneficial effect of swirling flow could have accounted for increased mixing. Conversely, VF = 9 swirling flow resulted in a 9% decrease of steady-state productivity and a 9% increase in the time required to reach this steady state, a negative effect that could have accounted for increased shear stress. CO(2) bioconversion yield at steady state showed a 34% increase for VF = 4. These results suggest that swirling motion makes microalgal cultures more efficient, provided that the resulting adverse effects remain acceptable. Experimental investigation was completed by a theoretical approach in which simulation of continuous cultures of P. cruentum was based on the hydrodynamic conditions achieved in the photobioreactor. Although the results obtained with pseudoaxial flow were correctly predicted, simulations with swirling flow showed a marked enhancement of productivity not observed experimentally. The influence of side effects induced by increased mixing (particularly hydrodynamic shear stress) was considered with respect to modeling assumptions. Comparison of experimental results with theoretical simulation provided a better understanding of the mixing effect, a key factor in improving the efficiency of such bioprocesses.

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Particle image velocimetry investigation of the flow-field of a 3D turbulent annular swirling decaying flow induced by means of a tangential inlet

Cited by 36 publications

References 2 publications

A new photobioreactor for continuous microalgal production in hatcheries based on external‐loop airlift and swirling flow

A new photobioreactor for continuous microalgal production in hatcheries based on external‐loop airlift and swirling flow

Optimizing the rotor design for controlled-shear affinity filtration using computational fluid dynamics

Swirling flow implementation in a photobioreactor for batch and continuous cultures of porphyridium cruentum

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