International audienceThe effect of micro-particles and interface aging on coalescence of millimetre-sized water drops withan oil/water interface is studied over long times. The system is not pure and interface contaminationgrows with time, resulting in a slow but continuous decrease of interfacial tension over time (from 35to 10 mN/m), which is measured in situ using an original technique. Without added micro-particles,coalescence times are randomly distributed and uncorrelated to drop diameter or interfacial tension. Inpresence of 10 !m size hollow glass particles at the oil/water interface, coalescence times become morereproducible and show a clear dependence upon drop diameter and interface aging. Results are consistentwith a classical drainage model assuming that the critical thickness at which interstitial film rupturesscales as the micro-particle diameter, a result that tends to validate the bridging scenario. Interestingly,the film retraction speed during the coalescence process does not follow theoretical predictions in aplanar geometry. High-speed imaging of the retracting film reveals that the hole rim is bending upwardwhile retracting, resulting in a strong slowdown of retraction speed. This is caused by the difference ofinterfacial tension between oil/drop freshly formed interfaces and the aged oil/water interface

Forced convective boiling experiments of HFE-7000 were conducted in earth gravity and under microgravity conditions. The experiment mainly consists in the study of a two-phase flow through a 6 mm diameter sapphire tube uniformly heated by an ITO coating. The parameters of the hydraulic system are set by the conditioning system and measurements of pressure drops, void fraction and wall temperatures are provided. High-speed movies of the flow were also taken. The data were collected in normal gravity and during a series of parabolic trajectories flown onboard an airplane. Flow visualisations, temperature and pressure measurements are analysed to obtain flow pattern, heat transfer and wall friction data.