From highly specialised to generally available modelling of shear induced particle migration for flow segregation based separation technology

Autor: H.M. Vollebregt, C.G.P.H. Schroën, I. Drijer, T. van de Laar
Rok vydání: 2018
Předmět:
Zdroj: Separation and Purification Technology, 192, 99-109
Separation and Purification Technology 192 (2018)
ISSN: 1383-5866
DOI: 10.1016/j.seppur.2017.10.001
Popis: Shear induced diffusion can be used to induce particle migration in flow, and this may be a lead to novel separation technology. Under specific conditions, depending on, amongst others, the ratio between channel height and particle diameter, larger particles preferentially move to the centre of a channel. It has been demonstrated earlier that separation and fractionation can be facilitated by this, leading to lower energy and water demand, and prevention of particle accumulation on sieves that have pores that are much larger than the particles. This situation is very different from regular (cross-flow) membrane filtration, in which particles are retained by the pores, and accumulate in various layers. Unfortunately, the underlying mechanisms of particle migration are not that well understood, and contradicting results are reported in literature. There is clearly a need for a unifying approach that can be used by many; therefore, we developed a CFD computer model that can readily be used, unlike the rather inaccessible computer models that are mostly reported in literature. We focus on particle–particle interactions of monodisperse suspensions in flow, for which we added momentum terms to the general momentum equation. We found amongst others that due to shear induced diffusion the particle volume fraction will be 1.7 times higher at the centre of the channel compared to the channel wall for a bulk particle volume fraction of 50%. Our results describe the experimental results, obtained under similar ideal conditions, to a high level of detail. Our findings are also in reasonable agreement with other modelling and experimental studies from literature, and the discrepancies are most probably due to non-ideal behaviour in the experiments and different approaches used in the models. The big advantage of using this software is that the model can be adapted readily by researchers not specifically trained in modelling or programming, but even more importantly, particle migration can now be used as a starting point in separation design since parameter and geometry studies will take less effort using this software.
Databáze: OpenAIRE
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