Simultaneous Heat and Momentum Transfer in Two-Phase Film Systems at Low Pressure

The heat and momentum transfer in a liquid–vapor two-phase film system at high temperature and low pressure is studied as applied to removal of highly volatile fractions from high-boiling liquids. It is shown that the working zone can be divided into two regions, namely, the initial heating region and the evaporation region. The height of the former region is much smaller than that of the latter. The velocity and temperature distributions in the system are investigated.