کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
632950 | 1456011 | 2015 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
A novel retentate spacer geometry for improved spiral wound membrane (SWM) module performance
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
تصفیه و جداسازی
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چکیده انگلیسی
The investigated novel retentate-spacer design comprises spherical nodes symmetrically connected with cylindrical filaments, thus forming a net-type structure with parallelogram unit-cells. Key feature of this configuration is the contact points (or small contact-regions) of nodes with bounding membranes, instead of filament-membrane contact lines characterizing the conventional unwoven-filament geometries; undesirable contact lines create “dead-flow” zones, that promote reduced mass-transfer (i.e. increased concentration polarization-CP) and fouling. Direct numerical simulations of the flow field and mass transfer, complemented by pressure drop and mass-transfer coefficient measurements, reveal the advantages of novel spacers. The flow field, and local shear-stress and mass-transfer-coefficient distributions on membranes, are rather uniform. The novel spacers, considering also the extensive flow constrictions between filaments and membranes, exhibit broader distributions of these time-averaged transport parameters, which extend to higher values (compared to conventional spacers), with insignificant percentage of zero values; a fairly uniform shear-stress distribution is also identified on spacer filaments. Thus, significant benefits are expected in mitigating CP and fouling phenomena in membrane operation. Friction losses show increased dependence on cross-flow velocity (compared to conventional designs), as they are affected more by flow-shearing at the membrane surfaces, than by form-drag. Useful pressure drop and mass-transfer correlations are obtained.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Membrane Science - Volume 488, 15 August 2015, Pages 129-142
Journal: Journal of Membrane Science - Volume 488, 15 August 2015, Pages 129-142
نویسندگان
Chrysafenia P. Koutsou, Anastasios J. Karabelas,