Computational fluid dynamics of marine discharge of hypersaline solution

ABSTRACT

Seeking an alternative for public water supply, the Water and Sewage Company of the State of Ceará launched a public biding for the implementation of a desalination plant. The hypersaline solution, discarded from the desalination process, will be dumped into the sea. Due to the density difference between the fluids, the outflow is divided into two regions: ascending jet, with large momentum; and descending fountain, where the flow is governed by the negative buoyancy. This research presents a computational fluid dynamics modeling of jets and fountains, through the Ansys Fluent software, focusing on the project conditions presented for the desalination plant in Fortaleza. The model was compared to the data available in the literature and then simulated for the characteristics of the Water and Sewage Company of the State of Ceará desalination plant. In addition, the results were compared to those obtained through simulations with the integral Visual Plumes software for different discharge angles (30°, 45°, 60° and 90°). The results revealed a good agreement with published data, generating the equation Z_m/D = 1,8 Fr, which is able to predict the height reached by the jets/fountains (Z_m), based on the diffuser diameter and the Froude number. The computational fluid dynamics simulations produced similar results as those obtained with Visual Plumes.

Keywords:
CFD; fluent; fountains; jets; brine; Visual Plumes