Courtesy of Dr Tuan Ta, Thames Water Utilities Ltd., England

Thames Water utilizes CFD simulation to investigate the performance and possible design of various water treatment processes. Adopted as a design tool in 1992, CFD contributes an understanding of the processes, allowing Thames Water to optimize or check design performance, to effectively troubleshoot, and to investigate scale-up.

Physics of the water treatment processes typically involve the flow of water in pipes/channels, combined air/water flows, wind-driven water flow, solid sedimentation, non-Newtonian fluid flows, heat transfer, mixing, chemical coagulation, and disinfection. While some processes have been extensively studied, many are still very much research topics. Geometries range from simple rectangular tanks to complex baffle/plate/pipe arrangements and detailed nozzle design.

CFD has proved to be a powerful tool for the understanding of processes and design studies. The examples shown here depict some of the many applications currently being studied at Thames Water.

Velocity vectors and contours in a contact tank. The inlet is a circular opening at the bottom of the tank, and the flow is from left to right.

Simulation of a single dissolved air flotation unit includes a two-phase calculation, with air/water volume fraction depicted here.

A deforming mask is used to simulate the dynamic changes of top water level in this service reservoir. Simulation time was reduced from 2 months to 3 days using the deformed mesh model.

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