  Thin film condensation is commonly present in numerous natural and artificial
processes. Phase-change driven passive heat spreaders such as heat pipes, which
are widely used in electronics cooling, employ a continuous condensation
process at the condenser region. When the wick structure of a heat pipe is
composed of grooves, the top surfaces of the walls (fins) located between
consecutive grooves function as the major source of condensation and the
condensate flows along the fin top into the grooves. Modeling of this
condensation problem is vital for the proper estimation of condensation heat
transfer, which constitutes the basis for the overall performance of an heat
pipe together with the evaporation process. In the current study, a solution
methodology is developed to model the condensation and associated liquid flow
in a fin-groove system. Conservation of mass and momentum equations, augmented
Young-Laplace equation and Kucherov-Rikenglaz equation are solved
simultaneously to calculate the film thickness profile. The model proposed
enables the investigation of the effect of disjoining pressure on the film
profile by keeping the fin-groove corner, where the film becomes thinnest,
inside the solution domain. The results show that dispersion forces become
effective for near isothermal systems with sharp fin-groove corners and the
film profile experiences an abrupt change, a slope break, in the close
proximity of the corner. The current study is the first computational
confirmation of this behavior in the literature.
