Edge effects on water droplet condensation

Marie-Gabrielle Medici (1, 2) , Anne Mongruel (1) , Laurent Royon (3) , Daniel Beysens (1, 4)

1 PMMH - Physique et mécanique des milieux hétérogenes (UMR 7636)
2 LPMC - Laboratoire de physique de la matière condensée
3 MSC - Matière et Systèmes Complexes
4 SBT - Service des Basses Températures

In this study is investigated the effect of geometrical or thermal discontinuities on the growth of water droplets condensing on a cooled substrate. Edges, corners, cooled/non cooled boundaries can have a strong effect on the vapor concentration profile and mass diffusion around the drops. In comparison to growth in a pattern where droplets have to compete to catch vapor, which results in a linear water concentration profile directed perpendicularly to the substrate, droplets near discontinuities can get more vapor (outer edges, corners), resulting in faster growth or less vapor (inner edges), giving lower growth. When the cooling heat flux limits growth instead of mass diffusion (substrate with low thermal conductivity, strong heat exchange with air), edge effects can be canceled. In certain cases, growth enhancement can reach nearly 500% on edges or corners.

Mots clés: water; edge; discontinuities; dropwise condensation; dew; breath figures; mass diffusion

Domaines: Physique [physics]

Marie-Gabrielle Medici, Anne Mongruel, Laurent Royon, Daniel Beysens. Edge effects on water droplet condensation. Physical Review Online Archive (PROLA), 2014, 90 (6), pp.062403. ⟨10.1103/PhysRevE.90.062403⟩. ⟨hal-01136630⟩