ABSTRACT
This chapter explains how the isotherms may be included into the equations of the hydrodynamics of wetting films. When a porous body is partly saturated by capillary condensate and wetting films, the liquid and vapor fluxes cannot be considered separately due to interaction between the fluxes: internal evaporation and condensation. In porous bodies, film flow towards the narrower pores results in the displacement of a gas bubble to the wider part of the pore. In the case of air retention within narrowed pores, spontaneous film flow towards sample surfaces may take place when the drying is stopped, for example in soils at night, when evaporation does not occur. A thermocrystallization film flow takes place together with thermocapillary movement in thin non-freezing water films on the capillary wall between ice menisci maintained at different temperatures. Direct measurements of the velocities of thermocrystallization film flow were performed on a section of a capillary between ice menisci maintained at different temperatures.
