Document Type : Original Article
Abstract
Sewage discharged into an ambient water system such as a river or sea is a serious problem in irrigation and drainage networks. Concerns about pollution require decreasing the initial dilution for disposal of brine wastewater into ambient environments. A quick and effective way to dilute dense waste flow is turbulence from a submerged jet. The present research investigated use of a buoyant jet at different vertical angles and fluid injection rates on dilution. Flow-3D was used for modeling. Angles of 30°, 37.5°, 45°, 52.5° and 60° were considered at concentrations of 10, 20, 30 and 40 g/l and different jet injection discharges. The experimental data was then used for verification and validation. The results showed that the RNG k-e turbulence model with an error of about 9.5% had acceptable accuracy in the prediction of jet trajectory properties of injection flow. These results also showed that increasing the length (LM) decreased the peak height of the trajectory curve. The quantitative findings showed that the difference between the distance ratio of the peak trajectory at a 45° angle was twice that of the 30° and 60° angles at the different densimetric Froude numbers. The maximum and minimum dilution values at the peak trajectory were 0.68 and 0.48, respectively. At the peak for the return point, the maximum and minimum values were 0.42 and 0.03, respectively.
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