A numerical analysis of dropwise condensation of nanofluid on an inclined plate

In In this paper nanofluids condensation heat transfer on an inclined flat plate is investigated. To do this, thermal resistances of single droplets are calculated and the total heat flux is evaluated using population balanced theory. The nanofluids include alumina, titanium dioxide and silver as nanoparticles and water as a base fluid. Effects of different surface inclinations, nanofluids types, and nanoparticles concentrations are investigated on the heat transfer. Nanofluids properties consisting of thermal conductivity, density, dynamic viscosity, and latent heat are extracted from literature and introduced into the equations. The results are compared with some experimental data in the same conditions. The Nusselt theory is used to compare the heat transfer rate of filmwise condensation with dropwise condensation. Inspecting the results shows that the heat transfer coefficient of a vertical plate is maximum, and decreases with decreasing in inclination due to lower washing rate of small droplets by sliding droplets. The results also show that the heat transfer coefficients of various nanofluids are different but they are constant all over the surface. As well as, addition of nanoparticles to the base fluid increases heat transfer rate. It can be seen that water-silver nanofluid has the maximum heat transfer rate among three beforehand mentioned nanofluids in the same conditions and the heat transfer rate increases with increase in volume fraction of nanoparticle for a specific nanofluid.