Example Simple Evaporator Problem

A simple example of molecular transport for a three-species problem is illustrated here. Consider evaporation of a liquid into a high-aspect-ratio tube open to air. The diffusive transport of species entering the vapor through evaporation can be solved as a onedimensional two-point boundary-value problem. 

Our objective in Ex 1.3 was the demonstratiou of a moving (evaporating or condensing) boundary in terms of a simple problem. Accordingly, we assumed the entire solar energy to be absorbed at the top surface of a liquid layer. In the more realistic case associated with solar ponds, this energy is absorbed over a thickness which may even extend beyond the depth of the pond. The present example deals with a simple problem for this case based on the assumption of a constant depth. 

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