Abstract
Circular feed spacers are used to enhance flow mixing in membrane modules and thereby improve their efficiency. However, this involves increased fouling when the spacers are mounted in a zigzag arrangement or high power consumption when submerged. In view of this, a two-dimensional computational model of fluid flow and mass transfer is used to investigate the impact of using an undulated insert as a turbulence promoter in a membrane application. Thus, this study focuses on the effect of varying the amplitude and wavelength of the insert on desalination performances of a narrow channel bounded by two semi-permeable membranes. According to computational fluid dynamics (CFD) simulations, under the considered operating conditions, the increase of the insert amplitude from 0.2 to 0.7 mm could reduce the salt accumulation on the membrane walls by ~ 2.7%, improve the permeate flux by ~ 1%, but drastically increase the axial pressure drop by ~ 1148%. Increasing the insert wavelength from 3 to 24 mm could promote salt accumulation on the membrane walls by ~ 4.8%, reduce the permeate flux by ~ 1.4%, but minimize the axial pressure drop by ~ 96%. Plots of the Sherwood number versus the Power number highlighted that the optimal insert must have a low amplitude and a short wavelength. Some of the insert geometries tested in this study generated better performances than commercial feed spacers, confirming the benefits of undulated inserts and suggesting their use in membrane separation processes.
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Abbreviations
- a:
-
Insert amplitude (m)
- \(D_{{{\text{AB}}}}\) :
-
Binary diffusion coefficient of the salt water (m2/s)
- \(\overline{f}\) :
-
Friction factor (−)
- H:
-
Channel height (m)
- Jv :
-
Permeate flux (m/s)
- k:
-
Mass transfer coefficient (m/s)
- L:
-
Total channel length (m)
- l 1 :
-
Reference length (m)
- mA :
-
Salt mass fraction (kg solute/ kg solution)
- p:
-
Pressure (Pa)
- Pn:
-
Power number (−)
- R:
-
Intrinsic rejection coefficient (%)
- Rm :
-
Hydraulic resistance of the membrane (m−1)
- Rech :
-
Feed Reynolds number based on the channel height H (−)
- u, v:
-
Velocity components in Cartesian coordinates (m/s)
- x, y:
-
Cartesian coordinates (m)
- Sh:
-
Sherwood number (−)
- \(\delta\) :
-
Concentration polarization layer thickness (m)
- \(\rho\) :
-
Density of the salt water (kg/m3)
- \(\mu\) :
-
Dynamic viscosity of the salt water (Pa s)
- \(\Delta {\text{P}}_{{{\text{tm}}}}\) :
-
Transmembranaire pressure (Pa)
- Δp:
-
Longitudinal pressure drop (Pa)
- π:
-
Osmotic pressure of the salt water (Pa)
- λ:
-
Insert wavelength (m)
- 0:
-
Inlet channel
- m:
-
Membrane surface
- w:
-
Pure water
References
Ahmad AL, Lau KK, Abu Bakar MZ, Abd Shukor SR (2005) Integrated CFD simulation of concentration polarization in narrow membrane channel. Comput Chem Eng 29:2087–2095
Amokrane M, Sadaoui D (2021) Improving the reverse osmosis desalination system with tilted oval spacers in a zigzag configuration. Desalin Water Treat 211:359–368
Amokrane M, Sadaoui D, Koutsou CP, Karabelas AJ, Dudeck M (2015) A study of flow field and concentration polarization evolution in membrane channels with two-dimensional spacers during water desalination. J Membr Sci 477:139–150
Amokrane M, Sadaoui D, Dudeck M, Koutsou CP (2016) New spacer designs for the performance improvement of the zig–zag spacer configuration in spiral-wound membrane modules. Desalin Water Treat 57:5266–5274
Borgohain P, Choudhary D, Dalal A, Natarajan G (2018) Numerical investigation of mixing enhancement for multi-species flows in wavy channels. Chem Eng Process 127:191–205
Dendukuri D, Karode SK, Kumar A (2005) Flow visualization through spacer filled channels by computational fluid dynamics-II: improved feed spacer designs. J Membr Sci 249:41–49
Dong F, Jin D, Xu S, Xu L, Xi Wu, Wang P, Leng Q, Xi R (2020) Numerical simulation of flow and mass transfer in profiled membrane channels for reverse electrodialysis. Chem Eng Res Des 157:77–91
Ferreira FB, Ullmann G, Vieira LGM, Cardoso VL, Reis MHM (2020) Hydrodynamic performance of 3D printed turbulence promoters in cross-flow ultrafiltrations of Psidium myrtoides extract. Chem Eng Process 154:108005
Fimbres-Weihs GA, Wiley DE (2010) Review of 3D CFD modeling of flow and mass transfer in narrow spacer-filled channels in membrane modules. Chem Eng Process 49:759–781
Geraldes V, Semião V, Pinho MN (2001) Flow and mass transfer modelling of nanofiltration. J Membr Sci 191:109–128
Guillen G, Hoek EMV (2009) Modeling the impacts of feed spacer geometry on reverse osmosis and nanofiltration processes. Chem Eng J 149:221–231
Haaksman VA, Siddiqui A, Schellenberg C, Kidwell J, Vrouwenvelder JS, Picioreanu C (2017) Characterization of feed channel spacer performance using geometries obtained by X-ray computed tomography. J Membr Sci 522:124–139
Haidari AH, Heijman SGJ, van der Meer WGJ (2018) Optimal design of spacers in reverse osmosis. Sep Sci Technol 192:441–456
Karabelas AJ, Kostoglou M, Koutsou CP (2015) Modeling of spiral wound membrane desalination modules and plants—review and research priorities. Desalination 365:165–186
Kavianipour O, Ingram GD, Vuthaluru HB (2017) Investigation into the effectiveness of feed spacer configurations for reverse osmosis membrane modules using Computational Fluid Dynamics. J Membr Sci 526:156–171
Koutsou CP, Yiantsios SG, Karabelas AJ (2004) Numerical simulation of the flow in a plane-channel containing a periodic array of cylindrical turbulence promoters. J Membr Sci 231:81–90
Koutsou CP, Yiantsios SG, Karabelas AJ (2007) Direct numerical simulation of flow in spacer-filled channels: Effect of spacer geometrical characteristics. J Membr Sci 291:53–69
Koutsou CP, Yiantsios SG, Karabelas AJ (2009) A numerical and experimental study of mass transfer in spacer-filled channels: effects of spacer geometrical characteristics and Schmidt number. J Membr Sci 326:234–251
Li F, Meindersma W, Haan AB, Reith T (2005) Novel spacers for mass transfer enhancement in membrane separations. J Membr Sci 253:1–12
Lin WC, Shao RP, Wang XM, Huang X (2020) Impacts of non-uniform filament feed spacers characteristics on the hydraulic and anti-fouling performances in the spacer-filled membrane channels: experiment and numerical simulation. Water Res 185:116251
Patankar SV (1980) Numerical heat transfer and fluid flow. Mc Graw-Hill, New York
Ranade VV, Kumar A (2006) Fluid dynamics of spacer filled rectangular and curvilinear channels. J Membr Sci 271:1–15
Saeed A, Vuthaluru R, Vuthaluru HB (2015a) Investigations into the effects of mass transport and flow dynamics of spacer filled membrane modules using CFD. Chem Eng Res Des 93:79–99
Saeed A, Vuthaluru R, Vuthaluru HB (2015b) Impact of feed spacer filament spacing on mass transport and fouling propensities of RO membrane surfaces. Chem Eng Commun 202:634–646
Schwinge J, Wiley DE, Fletcher DF (2002a) Simulation of the flow around spacer filaments between narrow channel walls. 1. Hydrodynamics. Ind Eng Chem Res 41:2977–2987
Schwinge J, Wiley DE, Fletcher DF (2002b) Simulation of the flow around spacer filaments between channel walls. 2. Mass-transfer enhancement. Ind Eng Chem Res 41:4879–4888
Schwinge J, Wiley DE, Fletcher DF (2002c) A CFD study of unsteady flow in narrow spacer-filled channels for spiral wound membrane modules. Desalination 146:195–201
Schwinge J, Wiley DE, Fletcher DF (2003) Simulation of unsteady flow and vortex shedding for narrow spacer-filled channels. Ind Eng Chem Res 42:4962–4977
Sioutopoulos DC, Yiantsios SG, Karabelas AJ (2010) Relation between fouling characteristics of RO and UF membranes in experiments with colloidal organic and inorganic species. J Membr Sci 350:62–82
Subramani A, Kim S, Hoek EMV (2006) Pressure, flow, and concentration profiles in open and spacer-filled membrane channels. J Membr Sci 277:7–17
Toh KY, Liang YY, Lau WJ, Fletcher DF (2020) CFD study of the effect of perforated spacer on pressure loss and mass transfer in spacer-filled membrane channels. Chem Eng Sci 222:115704
Valinataj-Bahnemiri P, Ramiar A, Manavi SA, Mozaffari A (2015) Heat transfer optimization of two phase modeling of nanofluid in a sinusoidal wavy channel using Artificial Bee Colony technique. Eng Sci Technol Int J 18:727–737
Vo DD, Alsarraf J, Moradikazerouni A, Afrand M, Salehipour H, Qi C (2019) Numerical investigation of γ-AlOOH nano-fluid convection performance in a wavy channel considering various shapes of nanoadditives. Powder Technol 345:649–657
Wardeh S, Morvan HP (2008) CFD simulations of flow and concentration polarization in spacer-filled channels for application to water desalination. Chem Eng Res Des 86:1107–1116
Xie P, Murdoch LC, Ladner DA (2014) Hydrodynamics of sinusoidal spacers for improved reverse osmosis performance. J Membr Sci 453:92–99
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Amokrane, M., Sadaoui, D. Undulated insert for boosting desalination efficiency in membrane systems. Braz. J. Chem. Eng. 38, 837–847 (2021). https://doi.org/10.1007/s43153-021-00151-0
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DOI: https://doi.org/10.1007/s43153-021-00151-0