Author(s): Ozeair Abessi; Philip J. W. Roberts
Linked Author(s):
Keywords: Marine discharge; Dense flow; Desalination; Rosette diffusers; Brine
Abstract: In this paper, laboratory experiments on rosette diffusers for dense discharge from seawater desalination plants are reported. The rosette diffuser consisted of 4 nozzles pointing upwards at 60 from the floor arranged 90 apart in planform. Single risers in two planform orientations were investigated. First where two nozzles are parallel to ambient flow and two others are perpendicular to the flow (0˚orientation) and second one where the riser oriented 45˚ from the flow. Threedimensional laser-induced fluorescence (3DLIF) was used to map the flow field configuration. Through a complicated calibration process the tracer concentration fields were identified and flow dilution and geometrical properties were calculated along the near field. The flow from rosette diffuser showed a three dimensional configuration in which flow of nozzles merge at downstream. For low ambient Froude number (UrF < 1) the dilution at impact point was estimated even lower than the stagnant condition which up to now assumed to be the worst case. The terminal rise height and the location of impact point were also calculated for riser in both configurations. The flow 3D configuration showed that flow maximum concentration at impact point does not essentially at the centerline. It also observed that discharged flow from 0˚ and 45˚ risers merge differently from each other and it causes that dilution from riser with 45˚ orientation give slightly better dilution than 0˚ risers.
Year: 2016