Analysis of flow and concentration fields in a baffled circular storage tank

Water storage tanks have been usually designed with two objectives, i.e. to provide a specified maximum storage volume and to establish a certain total head over the water supply network. Only more recently, some attention was paid to the water quality inside the storage tank since this can significantly affects the quality in the distribution systems. The paper presents some preliminary results of a numerical study undertaken to investigate hydrodynamics and turbulent mixing inside a circular storage tank. Two-dimensional steady-state and time-variable numerical simulations were performed with Multiphysics 3.4™ in a circular storage tank geometry. Four internal configurations of baffles were compared using the Morrill Index (MI) as main hydraulic performance indicator. Results demonstrated that the best MI value was achieved with a concentric baffle arrangement with a single inlet and outlet.