Numerical Analysis of Merging Flows of Floc-Forming Fluids in a T-Junction Channel Using a Non-Newtonian Viscous Model Based on a Population

Abstract

The flow of a floc-forming fluid in a T-junction channel was numerically analyzed using a non-Newtonian viscous model based on the population balance equation (PBE) of the floc size. The finite element method was applied to solve the velocity and pressure fields, and the PBE of the floc size distribution was computed to obtain the effective volume fraction of flocs. The Krieger-Dougherty model was used to evaluate the viscosity of suspension of flocs using the effective volume fraction. The numerical simulation captured the characteristic aggregation-breakage behavior of flocs in the flow. In the region where flows from two entrances merge, the effective volume fraction decreases because the breakage of flocs progresses. In the downstream channel, re-aggregation of flocs occurs near the channel centerline, and the effective volume fraction increases. This aggregation-breakage behavior of flocs was confirmed by the analysis of the floc size distribution.