DEM simulations of initial deposition of colloidal particles around non-woven membrane spacers

Abstract

The modelling of the initial deposition on membrane spacers of colloidal size particles immersed in a liquid is investigated using the Discrete Element Method (DEM). The ability of this method to model surface interactions allows the modelling of particle agglomeration and deposition at the particle scale. The numerical model adopts a mechanistic approach to represent the forces involved in colloidal suspension by including near wall drag retardation, surface interaction and Brownian forces. The model is implemented using the commercially available DEM package EDEM 2.3®, so that results can be replicated in a standard and user-friendly framework. The effect of different spacer orientation with respect to feed direction is examined and results show that deposition of particles are increased around the spacer joints when feed orientation bisects the spacers' angle; when one of the spacer filaments is aligned with the feed inflow deposition occurs exclusively and uniformly on it. Simulation results demonstrate the validity of such method to describe the small-scale behaviour of micro-particles around spacers.

Spacer geometry and particle deposition in spiral wound membrane feed channels

“…In this way, the particle transport in the bulk fluid presented in this study could be combined with DEM simulations including various forces (e.g., drag, shear-induced lift, etc.) acting on a particle in the vicinity of a wall (Chaumeil and Crapper (2013)). …”

Exploring the antifouling effect of elastic deformation by DEM–CFD coupling simulation

“…The bacterial adhesive kinetics, including bacterial motions and collisions, were simulated by coupling the Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD) methods for the rst time. 15,19 The simulations of particulates as described in this work can predict initial deposition patterns of both elastic membrane and rigid membrane. It evaluates the role of elastic deformation, which could inuence the bacteria adhesion.…”

“…Biofouling occurs via the formation of biofilm, which triggered by the adhesion of primary colonizing bacteria. 15 In the early stages of biofilm formation, physical interactions are the first forces for bacteria adhesion, which frequently influenced by the physical properties of interaction surface. 16 As previous reports, the micron-scale deformations are presented on elastic surface, and it is benefit to antifouling.…”

Colloidal fouling mitigation using pulsating flows in osmotic membrane processes

“…This leads to a frequency dependent decrease in recirculation zone downstream of the spacer filament and therefore a decrease in d ab . Chaumeil and Crapper [7] stated that areas with low wall shear stress are more likely to be affected by colloidal fouling. In the example of the zig-zag configuration that would be downstream of a spacer filament.…”

“…Chaumeil and Crapper [7] studied the initial deposition of colloidal particles around non-woven membrane spacers. They used the discrete element method in combination with CFD to study colloidal particles in a fluid.…”