Abstract:

Modeling and simulation of vacuum evaporation from the surface of a continuous falling liquid column were carried out to obtain a mechanism-based prediction for application in energy-efficient vapor-liquid separation process.The parameters governing the continuous flow of falling liquid column out-of an orifice were investigated to determine the critical conditions for breakup of the liquid column.The mechanism of evaporation from the free surface of liquid column was analyzed and a mathematical model of the system was set up.The simulation results were in good agreement with the experimental data.In an adiabatic flash vaporization, the temperature gradient near the interface on the liquid side was a sensitive indicator of evaporation rate.This means that the resistance of heat transfer mainly lies in the liquid phase, so that the evaporation rate can be enhanced by increasing the liquid velocity out-of the orifice and narrowing the orifice diameter but without the breakup of liquid column, or increasing the degree of superheat.