Author(s)

H.H. Saber & M.S. El-Genk

Abstract

Analytical expressions for the thickness at breakup, Am,,, of a liquid film flowing on vertical, adiabatic wall, subject to either counter-current or co-current gas flow(or interfacial shear), and for the corresponding wetting rate, rmn, are obtained. These expressions are derived based on the minimization of the total energy of stable liquid rivulet, forming following the breakup of the film and whose thickness is same as the film at breakup. The comparison with experimental measurements for a climbing water film showed excellent agreement. For co-current flow condition, increasing the interfacial shear (or gas velocity) and/or decreasing the equilibrium contact angle of the liquid with underlying wall, Q,, decreases both A- and rmn, which are smaller than those at zero shear stress. Conversely, for counter-current flow condition, increasing the gas velocity and/or increasing Bo, increases both A- and rm,,, which are larger than those at zero shear stress.

Keywords