A numerical approach for determining the resistance of fine mesh filters

Abstract

Characterizing the resistance of mesh filters, in terms of pressure drop as a function of flow velocity, is an important part of modeling any filtration process. Most commonly, filters are characterized experimentally, which can be costly and time-consuming. This motivates a generalized numerical approach for characterizing the resistance of mesh filters based on the flow through a representative segment of a filter. There is uncertainty, however, in the correct specification of boundary conditions such that the numerical results for flow through the small segment match the overall behaviour of the filter. In this work, an experimentally validated numerical approach is developed by examining the velocity and turbulence intensity experienced across the filter. It has been shown that the flow resistance results are not sensitive to the turbulence intensity, but depend greatly on the imposed flow velocity. Specifying the peak velocity as the boundary condition in the filter simulations resulted in a good match with experiments, while using the bulk velocity did not reproduce the experimental results.

Dynamic model validation and advanced polymer control for rotating belt filtration as primary treatment of domestic wastewaters

“…To determine the mesh resistance, steady-state experiments have been conducted by Sherratt et al, (2018b) using a pumped flow through a horizontal pipe containing a mesh filter, with pressure transducers on either side. Conducting these tests over a range of flow rates showed that the mesh resistance increases linearly with the bulk velocity in the pipe, as expressed by the following equation:…”

Numerical modeling and control of solids separation using continuously moving fine mesh filters

“…1, is used to determine the cake resistance as a function of cumulative filtered volume per unit area, assuming that the mesh resistance coefficients are known. The mesh resistance coefficients can be determined for a given case by relatively simple pressure drop experiments, or using computational fluid dynamics simulations (Sherratt et al, 2018). The experiment is performed by first transferring a known volume of water into the column, with the valve closed.…”

Carbon Footprint and Energy Recovery Potential of Primary Wastewater Treatment in Decentralized Areas: A Critical Review on Septic and Imhoff Tanks

“…The fundamental working principle of these technologies is based on physical and/or biological processes. Specifically, while some PTTs typically remove suspended solids only through physical processes such as settling [13] or filtration [14][15][16][17], other PTTs such as septic and Imhoff tanks incorporate an additional removal mechanism, namely anaerobic digestion [18,19]. The latter occurs consequently to the fact that, differently from primary clarifiers or rotating filters where separated solids are continuously removed, within septic and Imhoff tanks the solids are allowed to accumulate in the system over long periods.…”