Concentration Matters: Enhancing Particle Settling in Narrow Tilted Channels

TL;DR

This study investigates how tilt angle affects particle sedimentation in narrow channels, revealing a concentration-dependent optimal tilt and providing a predictive model to optimize settling rates in various applications.

Contribution

It introduces a concentration-dependent optimal tilt angle for sedimentation and validates a Brinkman model to predict flow profiles in tilted channels.

Findings

Existence of a concentration-dependent optimal tilt angle.

Flow profiles deviate from classical shapes at large tilt angles.

A Brinkman model accurately captures non-parabolic flow profiles.

Abstract

Particles are known to sediment faster in containers with tilted walls than in vertical ones, a phenomenon known as the Boycott effect. In this work, we investigate how the tilt angle influences sedimentation in narrow channels across different particle volume fractions. Using particle-resolved computational fluid dynamics simulations, we reveal that there exists a concentration-dependent optimal tilt angle that maximizes sedimentation rates. Furthermore, at large tilt angles, the flow profiles across the channel deviate from the classical parabolic shape. We show that these non-parabolic profiles can be accurately captured by a one-dimensional Brinkman model, providing a predictive framework for understanding and tuning sedimentation in tilted geometries. Our findings demonstrate the potential to control and optimize particle settling by adjusting the channel tilt according to particle concentration, opening new possibilities for design in industrial and laboratory processes.