Investigation of flow patterns and mass transfer in membrane module channels filled with flow-aligned spacers using computational fluid dynamics (CFD)

Santos, José G.; Geraldes, Vı́tor; Велизаров, Светлозар; Crespo, João G.

doi:10.1016/j.memsci.2007.07.036

Cited by 136 publications

(93 citation statements)

References 27 publications

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“…A CFD analysis focused also on the study of polarisation phenomena was published by Santos et al in 2007 [11]. The work was limited to the case of concentration polarisation in a Reverse Osmosis test cell.…”

Section: Cfd Modelling Of Spacer-filled Channelsmentioning

confidence: 99%

Membrane distillation heat transfer enhancement by CFD analysis of internal module geometry

Cipollina¹,

Micale²,

Rizzuti³

2011

Desalination and Water Treatment

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Module geometry optimisation can be a crucial matter in all separation processes using selective or hydrophobic membranes, e.g. Reverse Osmosis (RO), Membrane Distillation (MD). In fact the choice of suitable channel shape and size can dramatically affect the performance of the process. With reference to the membrane distillation process, temperature polarization phenomena and pressure drops along the channels largely affect the process efficiency (i.e. the efficient use of temperature driving force for the passage of vapour through the membrane) as well as pressure distribution, module mechanical resistance and pumping costs.Several works have been presented so far in literature on the fluid flow characterization of spacer-filled channels for the case of Reverse Osmosis modules, but only few works deal with the problem of MD modules optimization.The present work aims at the CFD simulation of the fluid flow and temperature fields within spacer-filled MD module channels for a variety of spacer geometries. Both commercial and custom made geometries have been simulated in order to identify the most important parameters affecting process efficiency. The commercial CFD code ANSYS CFX11.0 has been adopted to perform simulations.Results provide valuable information to identify the main features which an optimised spacer should possess in order to minimise T-polarization and pressure drops along the channel.

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Section: Cfd Modelling Of Spacer-filled Channelsmentioning

confidence: 99%

Membrane distillation heat transfer enhancement by CFD analysis of internal module geometry

Cipollina¹,

Micale²,

Rizzuti³

2011

Desalination and Water Treatment

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“…Mass transfer phenomena in reverse osmosis (RO) processes have been studied experimentally and theoretically for many decades in order to understand how water and solute permeation occur within membrane modules [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16], so as to identify the factors that determine the performance of membrane modules. One of the most critical mass transfer phenomena present in an RO membrane module is concentration polarisation (CP), which is caused by the accumulation of solute(s) rejected by a selective RO membrane, resulting in an elevated solute concentration on the membrane surface [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…In a spiral wound membrane (SWM) module, which is the type of module most widely used in large scale RO plants, spacers are inserted between membrane sheets to keep them apart [37]. Feed spacers also promote mixing by inducing vortices near the membrane surfaces, which can mitigate CP but at the expense of an increased pressure drop [2,5,10,12,17]. It is therefore important to elucidate the effects of spacers on mass and momentum transfer in an SWM module with the ultimate aim to improve module performance.…”

Section: Introductionmentioning

confidence: 99%

The effect of feed spacer geometry on membrane performance and concentration polarisation based on 3D CFD simulations

Adjiman

2017

Journal of Membrane Science

121

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Feed spacers are used in spiral wound reverse osmosis (RO) membrane modules to keep the membrane sheets apart as well as to enhance mixing. They are beneficial to membrane performance but at the expense of additional pressure loss. In this study, four types of feed spacer configurations are investigated, with a total of 20 geometric variations based on commercially available spacers and selected filament angles. The impact of feed spacer design on membrane performance is investigated by means of three-dimensional (3D) computational fluid dynamics (CFD) simulations, where the solution-diffusion model is employed for water and solute transport through RO membranes.Numerical simulation results show that, for the operating and geometric conditions examined, fully woven spacers outperform other spacer configurations in mitigating concentration polarisation (CP).When designed with a mesh angle of 60º, fully woven spacers also deliver the highest water flux, although the associated pressure drops are slightly higher than their nonwoven counterparts. Middle layer geometries with a mesh angle of 30º produce the lowest water flux. On the other hand, spacers with a mesh angle of 90º show the lowest pressure drop among all the filament arrangements examined. Furthermore, the computational model presented here can also be used to predict membrane performance for a given feed spacer type and geometry.

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“…with the same filament diameter and pitch) ideal spacer made by overlapped filaments. This configuration was investigated since overlapped net spacers are largely employed in many membrane separation processes [26,[34][35][36]. Since the fluid dynamics in RED processes is not well established and optimized, it is highly recommended to study also geometrical configurations which are not yet commercially available.…”

Section: Systems Under Investigationmentioning

confidence: 99%

“…They carried out 2D simulations to predict the flow field and the concentration polarization for the case of pressure-driven membrane separation processes (as reverse osmosis and ultrafiltration). Some years later, Santos et al [26] predicted via CFD the flow and the concentration field for the case of membrane filtration processes. In particular, 12 different spacer structures (ranging from single-layer to two-layer overlapped rectangular filaments spacers) were investigated under different hydrodynamic conditions.…”

Section: Introductionmentioning

confidence: 99%

CFD prediction of scalar transport in thin channels for reverse electrodialysis

Tamburini

Barbera

Cipollina

et al. 2014

Desalination and Water Treatment

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Abstract. Reverse ElectroDialysis (RED) is a very promising technology allowing the electrochemical potential difference of a salinity gradient to be directly converted into electric energy. The fluid dynamics optimization of the thin channels used in RED is still an open problem.The present preliminary work focuses on the Computational Fluid Dynamics (CFD) simulation of the flow and concentration fields in these channels. In particular three different configurations were investigated: a channel unprovided with a spacer (empty channel) and two channels filled with spacers, one made of overlapped filaments the other of woven filaments. The transport of two passive scalars, representative of the ions present in the solution, was simulated in order to evaluate concentration polarization phenomena. Computational domain effects were also addressed. Future work will address the inclusion of electrical effects along with the migrative transport of the ions in the channel.

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Investigation of flow patterns and mass transfer in membrane module channels filled with flow-aligned spacers using computational fluid dynamics (CFD)

Cited by 136 publications

References 27 publications

Membrane distillation heat transfer enhancement by CFD analysis of internal module geometry

Membrane distillation heat transfer enhancement by CFD analysis of internal module geometry

The effect of feed spacer geometry on membrane performance and concentration polarisation based on 3D CFD simulations

CFD prediction of scalar transport in thin channels for reverse electrodialysis

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