Effect of impeller design on the flow pattern and mixing in stirred tanks

Kumaresan, T.; Joshi, Jyeshtharaj B.

doi:10.1016/j.cej.2005.10.002

Cited by 267 publications

(129 citation statements)

References 26 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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“…The second term in Equation (18) is negligible for the axial flow impellers (Patwardhan & Joshi, 1999;Kumaresan & Joshi, 2006). Thus, the flow number (Fl) can be estimated for axial flow impellers from the following equation using Q P : have utilized the axial velocities obtained using CFD to calculate the flow numbers for Lightnin A100, A200, and A310 impellers ( Table 3.…”

Section: Calculation Of Impeller Flow Numbermentioning

confidence: 99%