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Energy dissipation and mixing characterization in continuous oscillatory baffled reactor

Ávila López, Marco Antonio. Energy dissipation and mixing characterization in continuous oscillatory baffled reactor. PhD, Genie des Procédés et de l'Environnement, Institut National Polytechnique de Toulouse, 2020

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The focus of this thesis is to study the macro and micromixing performance of a secondary component in the bulk flow and how it should be introduced into a COBR. The effect of the position of secondary feeds, the influence of the oscillatory conditions and power dissipation on the macro and micromixing performance is studied, using numerical simulations and experiments carried out in a commercial Nitech® OBR with smooth constrictions. Energy dissipation is calculated through CFD simulations using two different ways – via viscous energy dissipation and the mechanical energy balance, the latter being preferred due to its lower demand for a refined computational mesh. A dimensionless power density number is obtained and proposed as a useful tool in the prediction of power density in COBRs. The impact of the position where a secondary feed enters the COBR on the spatial mixing quality is studied, and shows that when the source position is chosen correctly, an increase in the velocity ratio enhances mixing performance from 2% to 87% of the perfectly mixed state. The influence of the oscillatory conditions and flow rate of a secondary feed on the micromixing quality is analysed. Micromixing performance does not appear to correlate directly with power density. However, higher amplitudes and lower frequencies are preferred over lower amplitudes and higher frequencies to have a better micromixing performance. An attempt at characterising macromixing in the COBR experimentally using a coloured tracer was made however unexpected mixing performance was observed. Some preliminary experiments therefore focused on the behaviour of the tracer upstream of the COBR as a function of the oscillatory conditions.

Item Type:PhD Thesis
Uncontrolled Keywords:
Institution:Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Laboratory name:
Research Director:
Poux, Martine and Aubin, Joelle
Deposited On:19 Oct 2020 10:22

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