Abstract
Employing inclined dense jets is a common way for the disposal of brine effluent from coastal desalination plants. This paper numerically analyzes the mixing and geometrical properties of 30° and 45° inclined dense jets when they discharge close to the bed. For this purpose, two series of numerical simulations were developed. First, the nozzle acts as a free jet when it is placed far enough from the lower boundary. Meanwhile, in the second series, the distance between the nozzle tip and seabed is substantially reduced. Consequently, by comparing these two series, the effect of proximity to bed on the behavior of dense jets is investigated. The governing equations are solved by modifying a solver within the CFD package of OpenFOAM. The numerical results are presented in comparative figures and compared to the previous works. Comparisons indicated that the numerical model predicts the geometrical characteristics of dense jets in good agreement with the past experimental studies. However, the dilution predictions are conservative. It has been observed that proximity to the bed has almost no appreciable effects on the behavior of 45° jets. However, for 30° jets, when the bed proximity parameter ( Y0/LM ) falls below 0.14, normalized values of horizontal and vertical locations of centerline peak and return point dilution are slightly reduced while the terminal rise height remains untouched.
Effect of Proximity to Bed on 30° and 45° Inclined Dense Jets: a Numerical Study
