New spacer designs for the performance improvement of the zigzag spacer configuration in spiral-wound membrane modules

Amokrane, Mounir; Sadaoui, Djamel; Dudeck, Michel; Koutsou, C.P.

doi:10.1080/19443994.2015.1022003

Cited by 13 publications

(6 citation statements)

References 38 publications

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“…The assessment of these flow variables is conceivable, deprived of any trouble to the primary flow. As an analysis method, CFD gives the permission to change fluid properties, operating conditions, and geometric characteristics of the flow channels in a flexible but defined way [9]. The geometric parameters of the channels change, deprived of the requirement to make and check new meshes.…”

Section: Introductionmentioning

confidence: 99%

A computational fluid dynamics (CFD) approach for the modeling of flux in a polymeric membrane using finite volume method

Ahsan

Hussain

2017

Mechanics & Industry

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The computational fluid dynamics (CFD) modeling in this study observes steady-state mass transfer in a polymeric membrane. The efficiency, robustness, and reliability of recent numerical methods for finding solutions to flow problems have given rise to the implementation of CFD as a broadly used analysis method for engineering problems like membrane separation system. This study is novel due to the implementation of userdefined scalar diffusion equation by using user-defined functions in finite volume method (FVM). During the implementation of governing equation and boundary conditions important details of the FVM are discussed in detail. In this research, the flux profile is reported calculated from the pressure gradient for a steady-state problem.

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Section: Introductionmentioning

confidence: 99%

A computational fluid dynamics (CFD) approach for the modeling of flux in a polymeric membrane using finite volume method

Ahsan

Hussain

2017

Mechanics & Industry

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“…The authors state that these can increase the mass transfer and together with the pressure drop, there may be an increase in process efficiency [17]. Amokrane et al [18] used a model based on CFD which combines the fluid dynamics and the mass transfer in SWMs with zig-zag spacers, to investigate the impact of new spacers design. They affirm that zig-zag arrangement appears to have more advantages in the performance of RO membranes, in comparison, with submerged spacers.…”

Section: Introductionmentioning

confidence: 99%

“…The results highlight that the incorporation of new spacer designs, such as elliptic and oval shapes, generates lower pressure drop (Δp) compared to conventional geometries. However, concentration polarization layer thickness, induced by elliptic and oval spacers, is higher compared to that of a circular spacer, while the mass transfer coefficient obtained with circular spacer is higher [18]. Al-Bastaki and Abbas [19] used a cyclic feed flow to improve the performance of membrane modules.…”

Section: Introductionmentioning

confidence: 99%

Pulsating Flow Effects on Hydrodynamics in a Desalination Membrane Filled with Spacers

Soares¹,

Silva²,

Monteiro³

et al. 2017

Desalination

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A previously developed and validated two-dimensional computational fluid dynamics (CFD) model to study the hydrodynamics in a desalination membrane filled with spacers in zigzag arrangements has been further developed to include the effects of a pulsating flow with the profile of a heartbeat. Numerical solutions were obtained with Fluent for pulsating laminar flows in channels filled with four different spacers and four lengths of cells. Hydrodynamics was investigated for unsteady state, using a characteristic function of a heartbeat, in order to study the influence of temporal variation in the hydrodynamic behavior. The results show the velocities distribution, streamlines, pressure drop and the wall shear stress on the impermeable wall of the membrane, for Reynolds numbers up to 100. The reduction in the distance between the filaments of the spacers, leads to the appearance of more active recirculation zones that can promote mass transfer and decreasing concentrations layers. On the other hand, this reduction increases the pressure drop and consequently the energy expended in the process. Further, the characteristic function of heartbeat demonstrates promising results, with regard to the energy consumption in the process and optimization of the recirculation zones.

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“…Due to the complexity of the phenomena, computational fluid dynamics (CFD) has recently become a technique of choice for the calculation of flow and concentration fields inside feed membrane channels. Thus for instance some studies simulated the flow and CP in narrow rectangular channels with spacers [6][7][8][9][10][11]. Their results show inhomogeneous CP distribution strongly dependent on the spacer configuration and reveal up to an order of magnitude variation in the local mass-transfer coefficient depending on the position along the membrane surface [10,[12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…This dependence can be essential as we will see below. In addition, even in the studies where the membrane boundary condition was used [7][8][9][10]13,14,19,20], reporting the results in terms of averaged Sherwood number (instead of reciprocal one) makes difficult drawing conclusions on the correlation between the averaged mass transfer and solute diffusion coefficient (especially when the CP is not weak). In turn, a previous study characterized shear stresses and mass transfer coefficients at the membrane surface of a high pressure stirred filtration cell at different conditions [21].…”

Section: Introductionmentioning

confidence: 99%

Implications of inhomogeneous distribution of concentration polarization for interpretation of pressure-driven membrane measurements

Labastida

Bernal

Yaroshchuk

2016

Journal of Membrane Science

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A number of CFD studies have demonstrated that there is a considerable inhomogeneity of extent of Concentration Polarization (CP) over the membrane surface especially in spacer-filled feed channels. However, the consequences of this inhomogeneity for the interpretation of measurements of solute rejection in pressure-driven membrane processes have received little attention. This study uses a simple model of locally-1D CP combined with a postulated probability distribution of unstirred-layer thickness over the membrane thickness. In this way, we obtain transparent analytical results and can consider qualitative consequences of inhomogeneous distribution of CP over membrane surface. Our analysis shows that disregarding the CP distribution underestimates the CP of strongly positively-rejected solutes and overestimates the CP for the negatively-rejected ones. This observation is especially important for the interpretation of ion rejection from multi-ion solutions in nanofiltration where strong positive and pronounced negative rejections can occur simultaneously for solutes of different charges. We conclude that for reliable interpretation of pressure-driven membrane measurements it is desirable to reduce the inhomogeneity of CP distribution to a minimum in membrane-testing devices.

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New spacer designs for the performance improvement of the zigzag spacer configuration in spiral-wound membrane modules

Cited by 13 publications

References 38 publications

A computational fluid dynamics (CFD) approach for the modeling of flux in a polymeric membrane using finite volume method

A computational fluid dynamics (CFD) approach for the modeling of flux in a polymeric membrane using finite volume method

Pulsating Flow Effects on Hydrodynamics in a Desalination Membrane Filled with Spacers

Implications of inhomogeneous distribution of concentration polarization for interpretation of pressure-driven membrane measurements

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