Numerical simulation of Dean vortices: fluid trajectories

Moll, Randall; Moulin, P.; Veyret, D.; Charbit, F.

doi:10.1016/s0376-7388(01)00606-8

Cited by 17 publications

(6 citation statements)

References 7 publications

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“…The formation of a secondary flow in helical or woven geometries increases the shear stress at the tube wall and limits fouling phenomena. The permeation is then improved, by a factor of 2.5 to 4, depending on the operating parameters, as reported in some publications (Moll, 2005;Moll et al, 2002;Moll et al, 2007a&b). Moreover, coiling ceramic membranes to give them a helical form enables suppression of possible turbulent fluctuations of the flow, so to hinder the turbulent flow emergence and increase the critical values of the Reynolds number, in comparison with a flow in a straight tube (Cioncolini and Santini, 2006).…”

Section: Introductionmentioning

confidence: 69%

Developing Lengths in Woven and Helical Tubes with Dean Vortices Flows

Springer

Carretier

Veyret

et al. 2009

Engineering Applications of Computational Fluid Mechanics

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Coiling membranes help to create in a flow Dean vortices which enhance flux permeation and bring improvement to membrane filtration processes. The Dean number enables prediction of the appearance of those vortices. As it increases, a secondary flow appears with one pair of vortices. However, this flow profile needs a certain length to be fully developed. For membrane processes, it is useful to know this developing length so one can calculate the exact membrane area under such Dean shear stress. Developing angles or lengths were already simulated for a parabolic and a uniform inlet flow for a torus. In this study, we determined numerically the developing length for different kinds of tori and for woven or helical tubes. The simulations featured parameters of wide ranges of validity: internal diameter (0.25-1 mm), coil diameter (4-32 mm), Reynolds number (0-400) and pitch (2-32 mm) for the helical shape.

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Section: Introductionmentioning

confidence: 69%

Developing Lengths in Woven and Helical Tubes with Dean Vortices Flows

Springer

Carretier

Veyret

et al. 2009

Engineering Applications of Computational Fluid Mechanics

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“…Passage of fluid through a spiral tube is known to generate Dean vortices which provide uniform mixing of the fluid . A spiral irradiation chamber is a key component of the UVivatec Lab system, designed for effecting viral inactivation of solutions of biotherapeutic products such as plasma derived proteins.…”

Section: Discussionmentioning

confidence: 99%

“…Dean vortices generated during the flow ensures controlled mixing and uniform exposure to UV‐C. Dean vortices consist of two counter‐rotating vortices and are typically formed by fluid passing through curved channels and spiral tubes …”

Section: Introductionmentioning

confidence: 99%

Fluid flow in a spiral device used for irradiation of biological fluids

Nikolof¹,

Prakash

Cleary

et al. 2013

Biotechnology Progress

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The manufacture of plasma-derived therapeutics includes dedicated viral inactivation steps to minimize the risk of infection. Traditional viral inactivation methods are effective for the removal and inactivation of enveloped viruses, but less effective against small nonenveloped viruses. UV-C irradiation has been demonstrated to be an effective means of inactivating such viruses. The UVivatec lab system consists of a spiral tube around an UV-C irradiation source. Flow of a solution through the chamber generates and ensures controlled mixing and uniform exposure to irradiation. A detailed assessment of the effect of flow rate, alternate cross sectional design and scale up of the irradiation chamber on Dean vortices was performed using the smoothed particle hydrodynamics method. The aim was to provide a basis for setting flow rate limits and using a laboratory scale apparatus to model viral inactivation in larger manufacturing scale equipment. The effect of flow rate related changes on the fluence rate was also investigated through chemical actinometry studies. The data were consistent with the simulations indicating that Dean vortices were present at low flow rates, but dissipated at higher flow rates through the spiral chamber. Importantly, this work also allowed a correlation between the small system and large scale system to be established. This will greatly facilitate process development and viral validation studies.

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“…Polymer coagulants have removed the hydrophobic NOM fractions effectively while highly charged polyelectrolyte led to better removal of humic acid (around 90%) [169]. The cationic polymers performance was significantly enhanced with increasing molecular weight and charge density indicating synergistic effects.…”

Section: Coagulationmentioning

confidence: 98%

Ceramic Microfiltration Membranes in Wastewater Treatment: Filtration Behavior, Fouling and Prevention

et al. 2020

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Nowadays, integrated microfiltration (MF) membrane systems treatment is becoming widely popular due to its feasibility, process reliability, commercial availability, modularity, relative insensitivity in case of wastewater of various industrial sources as well as raw water treatment and lower operating costs. The well thought out, designed and implemented use of membranes can decrease capital cost, reduce chemical usage, and require little maintenance. Due to their resistance to extreme operating conditions and cleaning protocols, ceramic MF membranes are gradually becoming more employed in the drinking water and wastewater treatment industries when compared with organic and polymeric membranes. Regardless of their many advantages, during continuous operation these membranes are susceptible to a fouling process that can be detrimental for successful and continuous plant operations. Chemical and microbial agents including suspended particles, organic matter particulates, microorganisms and heavy metals mainly contribute to fouling, a complex multifactorial phenomenon. Several strategies, such as chemical cleaning protocols, turbulence promoters and backwashing with air or liquids are currently used in the industry, mainly focusing around early prevention and treatment, so that the separation efficiency of MF membranes will not decrease over time. Other strategies include combining coagulation with either inorganic or organic coagulants, with membrane treatment which can potentially enhance pollutants retention and reduce membrane fouling.

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Numerical simulation of Dean vortices: fluid trajectories

Cited by 17 publications

References 7 publications

Developing Lengths in Woven and Helical Tubes with Dean Vortices Flows

Developing Lengths in Woven and Helical Tubes with Dean Vortices Flows

Fluid flow in a spiral device used for irradiation of biological fluids

Ceramic Microfiltration Membranes in Wastewater Treatment: Filtration Behavior, Fouling and Prevention

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