A new model for calculating specific resistance of aggregated colloidal cake layers in membrane filtration processes
✍ Scribed by Albert S. Kim; Rong Yuan
- Publisher
- Elsevier Science
- Year
- 2005
- Tongue
- English
- Weight
- 220 KB
- Volume
- 249
- Category
- Article
- ISSN
- 0376-7388
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✦ Synopsis
A simple model to evaluate hydrodynamic cake resistance due to filtered aggregates is developed in this study. An aggregate is treated as a hydrodynamically as well as geometrically equivalent solid core with a porous shell. Creeping flow past a swarm of the composite spheres is solved using Stokes' equation and Brinkman's extension of Darcy's law. The dimensionless drag force ( ) exerted on the composite sphere is analytically determined by four parameters: radius of the solid core, thickness of the porous shell, permeability of the aggregate, and occupancy fraction as defined in this paper. In certain limiting cases, converges to pre-existing analytical solutions for (i) an isolated impermeable sphere, (ii) an isolated uniformly porous sphere, (iii) an isolated composite sphere, (iv) a swarm of impermeable spheres, and (v) a swarm of uniformly porous spheres. This expression is then used to predict the specific resistance of aggregate cake formed on membrane surfaces.