Flow Generated by Pitched Blade Turbines I: Measurements Using Laser Doppler Anemometer

Ranade, V. V.; Joshi, Jyeshtharaj B.

doi:10.1080/00986448908940539

Cited by 120 publications

(51 citation statements)

References 3 publications

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“…propeller have therefore been modified as the impeller blade pitch, the impeller blade width, the shape of the impeller tip blade… to improve its performances. The impact of these modifications on hydrodynamics quantities such as the velocity field, the shear rate distribution, the turbulent kinetic energy distribution, has been studied, among others, by Kumaresan and Joshi (2006), Ranade and Joshi (1989) and in up-pumping mode, using PIV, PLIF (Planar Laser Induced Fluorescence) and input power measurements. From the comparison based on the velocity fields, the mixing time, the power consumption and the turbulent kinetic energy distribution at a given rotational speed, they concluded that there is no proof that high solidity ratio impellers generate less shear rate than conventional pitched blade turbines.…”

Section: Introductionmentioning

confidence: 99%

Axial impeller selection for anchorage dependent animal cell culture in stirred bioreactors: Methodology based on the impeller comparison at just-suspended speed of rotation

Collignon

Delafosse

Crine

et al. 2010

Chemical Engineering Science

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Animal cells, which are nowadays essential for the industrial production of proteinic compounds, are commonly cultivated inside stirred tank bioreactors. In case of anchorage dependent cells, they are usually fixed on microcarriers. The choice of agitation conditions (impeller type, rotational speed…) in this type of process is not an easy task as it has to fulfil three potentially conflicting goals: (1) maintaining microcarriers in complete suspension, (2) homogenizing the culture medium, and (3) limiting mechanical constraints generated by the hydrodynamics on the cells. The aim of this study is to present an original methodology to select the most appropriate axial impeller for this specific application. Seven propellers are preselected on basis of their characteristics available in the literature. Instead of comparing impellers at a given rotational speed or a given power input, they are compared at their respective minimum impeller rotational speed that leads to a complete microcarrier suspension, i.e. at their respective just-suspended speed N js . They are then compared at higher rotational speeds N, expressed as multiples of N js . The impeller classification is based on the intensity of mechanical constraints they produced, evaluated from: (1) the macro-shear rate quantified by the spatial derivative of time average velocity fields measured by P.I.V, (2) the micro-shear rate characterized by the ratio between the microcarrier diameter to the average Kolmogorov scale computed from power input measurements, and (3) Corresponding author: Tel: +32 4 366 47 22 -Fax:+32 4 366 28 18 E-mail address : mlcollignon@ulg.ac.be respectively). Moreover, the mechanical constraints they produce increase more slowly with the N/N js ratio than the mechanical constraints produced by other impellers. These propellers are thus even more advantageous if rotational speeds higher than the just-suspended speed have to be used

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Section: Introductionmentioning

confidence: 99%

Axial impeller selection for anchorage dependent animal cell culture in stirred bioreactors: Methodology based on the impeller comparison at just-suspended speed of rotation

Collignon

Delafosse

Crine

et al. 2010

Chemical Engineering Science

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“…In the published literature, the knowledge of flow pattern has been employed for the estimation of equipment performance such as mixing (Joshi and Sharma [62], Joshi [63], Ranade and Joshi [64], Ranade et al [65], and Kumaresan and Joshi [66]), heat transfer (Joshi et al [67], Dhotre and Joshi [68]), Sparger design (Dhotre et al [69], Kulkarni et al [70]), gas induction (Joshi and Sharma [71], Murthy et al [72]), and solid suspension (Raghava Rao et al [73], Rewatkar et al [74], and Murthy et al [75]). Joshi and Ranade [76] have discussed the perspective of computational fluid dynamics (CFD) in designing process equipment with their views on expectations, current status, and path forward.…”

Section: Preamblementioning

confidence: 99%

Large Eddy Simulation for Dispersed Bubbly Flows: A Review

Dhotre

Deen

Ničeno

et al. 2013

International Journal of Chemical Engineering

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Large eddy simulations (LES) of dispersed gas-liquid flows for the prediction of flow patterns and its applications have been reviewed. The published literature in the last ten years has been analysed on a coherent basis, and the present status has been brought out for the LES Euler-Euler and Euler-Lagrange approaches. Finally, recommendations for the use of LES in dispersed gas liquid flows have been made.

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“…Some of the applications of these are discussed in the subsequent sections. The governing equations for single phase flows, the EulerianEulerian approach and volume of fluid approach may be found in many text books (for example, Ranade [106], Ranade and coworkers [18,19,54,[108][109][110], and manuals of commercial CFD vendors). These are, therefore, not repeated and discussed here.…”

Section: International Journal Of Chemical Engineeringmentioning

confidence: 99%

CFD Simulation of Annular Centrifugal Extractors

Vedantam

Wardle

Tamhane

et al. 2012

International Journal of Chemical Engineering

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Annular centrifugal extractors (ACE), also called annular centrifugal contactors offer several advantages over the other conventional process equipment such as low hold-up, high process throughput, low residence time, low solvent inventory and high turn down ratio. The equipment provides a very high value of mass transfer coefficient and interfacial area in the annular zone because of the high level of power consumption per unit volume and separation inside the rotor due to the high g of centrifugal field. For the development of rational and reliable design procedures, it is important to understand the flow patterns in the mixer and settler zones. Computational Fluid Dynamics (CFD) has played a major role in the constant evolution and improvements of this device. During the past thirty years, a large number of investigators have undertaken CFD simulations. All these publications have been carefully and critically analyzed and a coherent picture of the present status has been presented in this review paper. Initially, review of the single phase studies in the annular region has been presented, followed by the separator region. In continuation, the two-phase CFD simulations involving liquid-liquid and gas-liquid flow in the annular as well as separator regions have been reviewed. Suggestions have been made for the future work for bridging the existing knowledge gaps. In particular, emphasis has been given to the application of CFD simulations for the design of this equipment.

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Flow Generated by Pitched Blade Turbines I: Measurements Using Laser Doppler Anemometer

Cited by 120 publications

References 3 publications

Axial impeller selection for anchorage dependent animal cell culture in stirred bioreactors: Methodology based on the impeller comparison at just-suspended speed of rotation

Axial impeller selection for anchorage dependent animal cell culture in stirred bioreactors: Methodology based on the impeller comparison at just-suspended speed of rotation

Large Eddy Simulation for Dispersed Bubbly Flows: A Review

CFD Simulation of Annular Centrifugal Extractors

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