03158nam a2200277 a 4500 vtls000098241 KUKTEM 20251117113335.0 161202t2015 at a f 000 0 eng d THE0004173(Local) 201905141721 farhana 201710090900 aishah 201612021119 huda UMP TP156.O7 L53 2015 r Thesis Liang, Yong Yeow Concentration polarisation minimisation in membrane channels through electro-osmotic mixing / Liang Yong Yeow Australia : University of New South Wales, 2015 xv, 162 p. : ill. (some col.) ; 30 cm + 1 CD-ROM Thesis (Doctor of Chemical Engineering) -- Universiti of New South Wales - 2015 Bibliography : p. 153-161 Reverse osmosis (RO) promises to play an increasingly crucial role in watersupply, especially via desalination. One of the major problems faced by RO technologyis the decline in membrane performance due to concentration polarisation (CP) andfouling. CP increases the osmotic pressure gradient across the membrane, hencereducing the net driving pressure gradient. Moreover, CP increases the probability of fouling.An electro-osmosis technique is proposed in this thesis which has the potentialto reduce CP because it induces the movement of fluid in the vicinity of membrane, thus improving mixing within the boundary layer and enhancing mass transfer.Computational Fluid Dynamics (CFD) is used to simulate steady and unsteady electroosmotic flow (EOF) in 2D unobstructed and obstructed channels.First, a mathematical simplification of EOF is developed that reduces therequired computational load while retaining the model’s accuracy and physical meaning. It is shown that EOF can be mimicked using a slip velocity. The results from CFD are found to be in good agreement both with published data and with morerigorous simulation approaches.For steady EOF in unobstructed channels, the spatial variation in slip velocity is found to be the driver for mass transfer enhancement. For uniform-unsteady EOF in unobstructed channels, a sinusoidal time-varying electro-osmotic slip velocity has negligible effect on the time-averaged hydrodynamics and mass transfer, because the effect is nullified within the time oscillation period. Nevertheless, there are still benefits for using unsteady EOF for fouling reduction/prevention, as increases in slip velocity ii frequency and amplitude increase the maximum wall stress which is a proxy for fouling reduction.For unsteady EOF in spacer-filled channels, the simulation results show that anoscillating slip velocity has the potential to induce vortex shedding. This occurs when a resonant slip velocity frequency is used for Reynolds numbers near the transition from steady to unsteady flow. Reverse osmosis Membranes (Technology) Water Purification Reverse osmosis process http://ecollib.ump.edu.my/26003/ Library access only 0 0 lcc 0 6 10000 10000 2019-09-04 0 TP156.O7 L53 2015 r Thesis 0000113701 2019-09-04 00:00:00 1 2019-09-04 THESIS 0 0 lcc 0 1 10000 10000 2019-09-04 0 CD 10008 | TP156.O7 L53 2015 r Thesis 0000113702 2019-09-04 00:00:00 1 2019-09-04 THESIS VIRTUA40 7019 7025 VTLSSORT0080*0200*0400*0900*1000*2450*2600*3000*5020*5040*5200*6500*6501*6502*8560*9992