  Estimation of condenser performance of two-phase passive heat spreaders with
grooved wick structures is crucial in the prediction of the overall performance
of the heat spreader. Whilst the evaporation problem in micro-grooves has been
widely studied, studies focusing on the condensation on fin-groove systems have
been scarce. Condensation on fin-groove systems is actually a multi-scale
problem. Thickness of the film near the fin-groove corner can decrease to
nanoscale dimensions, which requires the inclusion of nanoscale effects into
the modeling. While a few previous studies investigated the effect of
dispersion forces, the effect of structural forces has never been considered in
the thin film condensation modeling on fin-groove systems. The present study
utilizes a disjoining pressure model which considers both dispersion and
structural forces. The results reveal that structural forces are able to
dominate dispersion forces in certain configurations. Consequently, by
intensifying the disjoining pressure, structural forces lead to a sudden change
of the film profile (slope break) for subcooling values which are relevant to
engineering applications.
