Some Basic Observations on Heat Transfer and Evaporation in the Horizontal Flash Evaporator

This paper decribes a study of the heat, mass and momentum transp associated with vapor release in a horizontal stage of a flash evaporat A scaled-down, well-controlled flash evaporator, which also allows gc visual observation, has been designed, constructed and used in the expl ments. In particular, temperature profiles in the stage have been measured an accuracy of ±O.02°C and better. It has been determined that the subcritical flow in the flash stage consi of two principal regions: submerged sluice gate flow with the associa1 hydraulic jump overlayed by a backflow roller, followed by open chanl flow. The flashirig of NaCI solutions was accompanied by strong foamil which has reduced the fractional non~equilibrium allowance by a factor two or three, without impairing the purity of the distillate.