The effect of filament orientation on critical flux and particle deposition in spacer-filled channels

Experiments have been conducted using the direct observation through the membrane (DOTM) technique to determine the effect of the presence and orientation of spacers on the critical flux of particles. It was found that spacers significantly enhance (up to 2 times) critical flux of 6.4 μm latex beads. The degree of enhancement depended on spacer orientation. When the attached filament was perpendicular to flow (90° orientation), deposition occurred in a transverse band across the entire spacer cell, set back from the transverse filament by a zone of no deposition. With the reverse orientation (0°—transverse filaments opposite the membrane), deposition occurred at higher fluxes and was concentrated around the attached filament parallel to flow. Whilst with the attached filaments arranged at 45° to flow, deposition occurred particularly in the centre of the cell. The critical fluxes and deposition patterns are in qualitative agreement with the anticipated fluid flow patterns through the spacer-filled channels. A discussion of the errors and implications of these results for industrial systems is also included.