Book Description

The results of an experimental and analytical study of deep submerged multiple-port thermal discharges are presented. The experimental results include the measured downstream thermal dilution, width, and centerline trajectory of the buoyant thermal plume from multiport jets. Independent parameters for which measurements were obtained include port spacing, discharge Froude Number, discharge angle, and discharge to ambient velocity ratio. Results indicate that decreasing port spacing greatly decreases thermal dilution. Changing port spacing will also affect trajectory to a small extent while only slightly changing plume width. Altering the Froude Number appears to have little effect on downstream dilution, width, or trajectory when an ambient current is present. By increasing discharge angle from the horizontal, greater initial dilution may be obtained as well as greater widths and higher trajectories. The effect of ambient current on dilution depends on the angle of discharge. For crossflow discharges the thermal dilution at any point downstream decreased with increasing ambient current, while for co-flow the reverse was observed. The jets were bent over rapidly for crossflow discharges particularly when large ambient currents were present. The analytical portion of this report employs the lumped differential model of Hirst as modified for merging multiple jets by Davis. The essential features of the analysis are: 1) the gradual transition of the profiles from simple axisymmetric profiles to merging profiles and finally to fully merged, pseudoslot, two-dimensional profiles, and 2) an entrainment based on the available entrainment surface. Results indicate that the overprediction of plume characteristics associated with "transition" or "equivalent slot" models may be overcome using such an analysis and that suitable prediction may be obtained