Predicting colloid transport and deposition in an array of collectors

Abstract

Colloid transport and deposition are influenced by pore structures and transport history. In contrast to the homogeneous single-collector efficiency assumption in the classical colloid filtration theory (CFT), it is realized that for accurate prediction of deposition the pore geometry and variation of single-collector efficiency along the transport direction need to be carefully considered. The axisymmetric Happel sphere-in-cylinder array models are developed. Comprehensive sets of numerical simulations are performed covering a wide range of parameters. We propose an upscaling equation of deposition rate coefficient by adopting the average collector efficiency and the array geometric model. The predictions based on the proposed model are compared with those from the classical CFT and previous experiments. We find that the collector efficiencies decrease substantially along the array in most natural conditions, especially within the first few collectors, which is attributed to the gravitational sedimentation and interception mechanisms. Detailed comparison with existing experimental data demonstrates that the upscaled model more accurately predicts the deposition rate than the equations based on single-collector efficiencies, especially for small and large colloids. Our work suggests the significance of considering array packing structures in CFT and can have implications for predicting colloid transport in industrial and field applications.