Heat transfer in stratified flow.

Abstract

When water is drawn from a cooling pond, heated by some industrial process and discharged "back into the pond to dissipate its heat load to the atmosphere an orderly motion is generated within the pond. This motion and the subsequent heat transfer from the surface of the pond is governed by the inlet Densimetric Proude Number, the inlet Reynolds Number, and the rate of heat transfer from the surface. In this dissertation, a two-dimensional cooling pond has been studied. The heated water is discharged onto the surface of the pond and, after losing heat at the surface, is eventually withdrawn from the bottom of the pond. The laminar equations of motion and the boundary conditions describing the problem have been approximated using finite differences and the equations have been solved using a numerical technique. The results of this mathematical model have been compared with the results of a laboratory-scale experimental investigation of the problem. The experimental results have also been compared with those obtained from a modified form of the mathematical model proposed by Koh and Fan for surface buoyant jets. Under steady state conditions the flow consists of a surface layer entraining fluid from below and losing heat at the surface. This layer subsides at the downstream boundary of the pond and passes through the pond outlet. A recirculation eddy is formed under the surface flow to replenish fluid entrained into the surface layer.