Hydraulic design of baffles in disinfection contact tanks

Abstract

This study focuses on understanding the hydraulic design of baffled contact tanks using computational fluid dynamics simulations. In particular, we address the key question: for a given footprint of a rectangular tank with a specified inlet width (Winlet), how does the hydraulic efficiency of a baffled tank depend on the configuration of internal baffles? In an effort to address this question, a carefully conceived parametric study consisting of 30 high-resolution two-dimensional (planar) simulations was conducted to quantify the hydraulic efficiency of a laboratory scale tank as a function of dimensional relationships between key baffle design dimensions (baffle opening length Lbo, baffle channel width Wch, and baffle channel length LT). Simulated longitudinal velocity profiles and flow through curves show good agreement with previous experimental results. The results indicate that the hydraulic efficiency can be optimized by ensuring that Lbo/Wch≈ 1 and orienting baffles along the longer direction of the rectangular footprint.