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Free surface, flow and mixing characterisation in orbitally shaken reactors

Li, Yi; (2020) Free surface, flow and mixing characterisation in orbitally shaken reactors. Doctoral thesis (Ph.D), UCL (University College London).

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Abstract

This thesis provides an experimental investigation of the free surface and flow dynamics within square orbitally shaken reactors (OSRs) as well as a mixing dynamics characterisation in shaken microwell systems. OSRs have been widely used for early bioprocess development as they allow a large number of experiments to be performed in parallel. It is necessary to develop robust scaling laws and determine effective dimensionless characteristics across shaken systems with various scales and geometries to facilitate bioprocess research and development. The fluid dynamics of shaken cylindrical reactors are well characterised by a number of previous studies, however, the understanding of square OSRs is still very limited despite its practical prevalence in bioprocessing. In the first part of the study, the free surface dynamics were investigated and different wave patterns and the relationship between the wave amplitude with respect to Froude number and the natural frequency of the system were identified in two square rectors with widths of 62 and 89 mm. Particle Image Velocimetry measurements were also obtained in the two square reactors and counter-rotation of the ensemble-averaged flow at high speed conditions were noticed. The flow transition occurring in square reactors was further investigated by means of Proper Orthogonal Decomposition. Despite the widespread use of shaken microwell plates, they have not been characterised from an engineering viewpoint. In the second part of the study, mixing time measurements were conducted into two intermediate-sized reactors and two microwell mimics for small orbital diameter shaker with do = 3 mm and compared against measurements obtained in lab-scale reactors for larger orbital diameter. A scaling parameter based on the natural frequency of the system, which depends only on fill volume, size and cross-section of the reactors, was proved to provide effective scaling across various shaken systems.

Type: Thesis (Doctoral)
Qualification: Ph.D
Title: Free surface, flow and mixing characterisation in orbitally shaken reactors
Event: UCL (University College London)
Language: English
Additional information: Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request.
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Biochemical Engineering
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering
URI: https://discovery.ucl.ac.uk/id/eprint/10095730
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