need to check the cross flow velocity in commercially available 8" spiral bound membrane in my design for reducing chances of formation of gel layer on the surface of membrane, during whey separation system.
Some methods in links below:
http://biofilms.bt.tudelft.nl/pdf/2010_JMemSci_2_Vrouwenvelder-et-al.pdf
http://biofilms.bt.tudelft.nl/pdf/2014_Desalination_1_Bucs-et-al.pdf
http://biofilms.bt.tudelft.nl/pdf/2014_WaterResearch_7_Radu-et-al.pdf
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=17&cad=rja&uact=8&ved=0CFUQFjAGOApqFQoTCMLVq8XPzsgCFcmXgAodoc0LYA&url=https%3A%2F%2Fconservancy.umn.edu%2Fbitstream%2F158160%2F1%2FG_umn_0130E_14059.pdf&usg=AFQjCNFYJxJl_H96SCDgHwP934xZFNgexA&bvm=bv.105454873,d.eXY
http://www.seas.ucla.edu/stenstro/CEE253paper3.pdf
http://media.sterlitech.com/pdfs/SEPA_CF_Instruction_Manual.pdf
http://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=2804&context=etd
http://infohouse.p2ric.org/ref/33/32101.pdf
http://infohouse.p2ric.org/ref/21/20781.pdf
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=15&cad=rja&uact=8&ved=0CEYQFjAEOApqFQoTCMLVq8XPzsgCFcmXgAodoc0LYA&url=http%3A%2F%2Fwww.dtic.mil%2Fcgi-bin%2FGetTRDoc%3FAD%3DADA298625&usg=AFQjCNEYj_IjM5Pl3zB5FTg_RuBZ2qRSGA&bvm=bv.105454873,d.eXY
http://www.lenntech.com/Data-sheets/Filmtec-Reverse-Osmosis-Product-Catalog-L.pdf
Dear Dinkar, maybe the following is useful:
1. Determine the membrane module feed water flow in m3/s
2. Determine the membrane module feed side surface area (m2)
3. Divide (1)/(2) and you have the linear flow velocity (m/s) at the inlet side of the membrane module. The linear velocity declines over the membrane module length due to permeate production. Determining the gradient in linear flow velocity requires either the membrane module permeate or concentrate flow.
How to determined (2): The total membrane module feed surface area (2) can be calculated using the cumulative length of the membrane module envelopes multiplied with the feed spacer thickness (usually 28 or 34 mil, which has to be converted to meters) and with the feed spacer porosity (usually between 0.82 and 0.84). The total membrane envelope length can be assessed by (i) measuring after destructive opening of a membrane module and (ii) calculating the membrane surface area from the membrane module and the effective membrane length. The membrane surface area, effective membrane surface area, feed spacer thickness and porosity data can be found using the specs from the membrane module manufacturer. Otherwise contact the membrane module supplier directly.
Best regards, Hans
For simple calculation, cross flow velocity can be calculated by taking the feed flow rate divided by the cross sectional area of feed channel spacer. For example, spiral wound module with 8 inch diameter which consist of four layer spacer with 40 mil thickness and 40 inch width. Then, cross section for feed will be,
A = 0,04 inch x 40 inch x 4 layer = 6,4 sq. Inch = 0,0111 sq.ft
If feed flowrate is 44 gpm (0,098 cu.ft/s), then
CVF = 0.098/0.111=0,883 fps
More detailed calculation can be made by considering spacer geometry using CFD. Several literature is also available :
1. J.S. Vrouwenvelder, C. Picioreanu, J.C. Kruithof, M.C.M. van Loosdrecht. 2010. Biofouling in spiral wound membrane systems: three-dimensional CFD model based evaluation of experimental data. Journal of Membrane Science. 346. 71-85
A.L. Ahmad, K.K. Lau, 2006. Impact of different spacer filaments geometries on 2D unsteady hydrodynamics and concentration polarization in spiral wound membrane channel. Journal of Membrane Science. 286. 77-92
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