Effect of feed spacer size and mesh length on permeate flux enhancement driven by forced slip velocity

Spiral-wound membrane (SWM) modules have been an important role in industrial desalination and water treatment processes. Concentration polarisation (CP) is a critical problem for membrane processes because prolonged solute accumulation near the membrane surface reduces the membrane performance and...

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Main Author:	Foo, Kathleen
Format:	Thesis
Language:	English
Published:	2020
Subjects:	TP Chemical technology
Online Access:	http://umpir.ump.edu.my/id/eprint/31330/1/Effect%20of%20feed%20spacer%20size%20and%20mesh%20length%20on%20permeate%20flux%20enhancement%20driven.pdf
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spelling	my-ump-ir.313302021-04-26T06:44:52Z Effect of feed spacer size and mesh length on permeate flux enhancement driven by forced slip velocity 2020-06 Foo, Kathleen TP Chemical technology Spiral-wound membrane (SWM) modules have been an important role in industrial desalination and water treatment processes. Concentration polarisation (CP) is a critical problem for membrane processes because prolonged solute accumulation near the membrane surface reduces the membrane performance and promotes fouling. Recent studies have shown that the interactions between forced transient flow and eddy inducers (i.e. spacers) in the SWM modules result in significant permeate flux enhancement and reduction in concentration polarisation. Forced slip velocity is the movement of thin fluid layer adjacent to the membrane surface, which disrupts the concentration boundary layer and promotes mixing in membrane systems. The aim of this thesis is to study the effect of SWM feed spacer geometry on the resonant frequency of forced-slip and the resulting permeate flux enhancement generated by forced-slip perturbation. This thesis uses Computational Fluid Dynamics (CFD) code to simulate and investigate the effect of varying the spacer geometric parameters on the resonant frequency for an unsteady forced-slip, as well as the resulting membrane performance, for a 2D zig-zag spacer. The analysis shows that the resonant frequency is significantly affected by the interaction of the shear layer with successive downstream spacers. The effectiveness of forced-slip reaches a peak (up to 15.6% flux increase) for a spacer size in the range of 0.5<df/hch<0.6 because of the trade-off between mixinginduced forced-slip and the CP modulus. In addition, vortex shedding is suppressed for smaller spacer sizes (df/hch≤0.4), because viscous forces dominate over convective forces due to a smaller filament Reynolds number. As the distance between filaments is increased, the increase in flux due to forced-slip is greater (up to 31.5%), albeit the actual flux decreases because the boundary layer is more developed. These results also reinforce the finding that forced-slip perturbation is more efficient for spacer designs with poor mixing (i.e. high CP). 2020-06 Thesis http://umpir.ump.edu.my/id/eprint/31330/ http://umpir.ump.edu.my/id/eprint/31330/1/Effect%20of%20feed%20spacer%20size%20and%20mesh%20length%20on%20permeate%20flux%20enhancement%20driven.pdf pdf en public masters Universiti Malaysia Pahang Faculty of Chemical and Process Engineering Technology
institution	Universiti Malaysia Pahang Al-Sultan Abdullah
collection	UMPSA Institutional Repository
language	English
topic	TP Chemical technology
spellingShingle	TP Chemical technology Foo, Kathleen Effect of feed spacer size and mesh length on permeate flux enhancement driven by forced slip velocity
description	Spiral-wound membrane (SWM) modules have been an important role in industrial desalination and water treatment processes. Concentration polarisation (CP) is a critical problem for membrane processes because prolonged solute accumulation near the membrane surface reduces the membrane performance and promotes fouling. Recent studies have shown that the interactions between forced transient flow and eddy inducers (i.e. spacers) in the SWM modules result in significant permeate flux enhancement and reduction in concentration polarisation. Forced slip velocity is the movement of thin fluid layer adjacent to the membrane surface, which disrupts the concentration boundary layer and promotes mixing in membrane systems. The aim of this thesis is to study the effect of SWM feed spacer geometry on the resonant frequency of forced-slip and the resulting permeate flux enhancement generated by forced-slip perturbation. This thesis uses Computational Fluid Dynamics (CFD) code to simulate and investigate the effect of varying the spacer geometric parameters on the resonant frequency for an unsteady forced-slip, as well as the resulting membrane performance, for a 2D zig-zag spacer. The analysis shows that the resonant frequency is significantly affected by the interaction of the shear layer with successive downstream spacers. The effectiveness of forced-slip reaches a peak (up to 15.6% flux increase) for a spacer size in the range of 0.5<df/hch<0.6 because of the trade-off between mixinginduced forced-slip and the CP modulus. In addition, vortex shedding is suppressed for smaller spacer sizes (df/hch≤0.4), because viscous forces dominate over convective forces due to a smaller filament Reynolds number. As the distance between filaments is increased, the increase in flux due to forced-slip is greater (up to 31.5%), albeit the actual flux decreases because the boundary layer is more developed. These results also reinforce the finding that forced-slip perturbation is more efficient for spacer designs with poor mixing (i.e. high CP).
format	Thesis
qualification_level	Master's degree
author	Foo, Kathleen
author_facet	Foo, Kathleen
author_sort	Foo, Kathleen
title	Effect of feed spacer size and mesh length on permeate flux enhancement driven by forced slip velocity
title_short	Effect of feed spacer size and mesh length on permeate flux enhancement driven by forced slip velocity
title_full	Effect of feed spacer size and mesh length on permeate flux enhancement driven by forced slip velocity
title_fullStr	Effect of feed spacer size and mesh length on permeate flux enhancement driven by forced slip velocity
title_full_unstemmed	Effect of feed spacer size and mesh length on permeate flux enhancement driven by forced slip velocity
title_sort	effect of feed spacer size and mesh length on permeate flux enhancement driven by forced slip velocity
granting_institution	Universiti Malaysia Pahang
granting_department	Faculty of Chemical and Process Engineering Technology
publishDate	2020
url	http://umpir.ump.edu.my/id/eprint/31330/1/Effect%20of%20feed%20spacer%20size%20and%20mesh%20length%20on%20permeate%20flux%20enhancement%20driven.pdf
_version_	1783732167346487296

Effect of feed spacer size and mesh length on permeate flux enhancement driven by forced slip velocity

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