Condensation of water vapor into liquid droplets on a cold surface is a widely observed phenomenon that manifests itself through patterns called "breath figures". Condensation is central to many natural and industrial processes, ranging from thermal management, desalination or dew water harvesting. In a first part, I will present lab experiments exploring different aspects of the physics of water condensation from humid air: nucleation on the substrate, further growth of droplets, coalescences and drainage by gravity. I will give recent examples of manipulation of droplets achieved by tayloring the texture and the wettability of surfaces. In a second part, I will discuss the efficiency of natural dew harvesting systems, capable of condensing atmospheric humidity on outdoor surfaces subjected to radiative sky cooling. Here, specific optical properties of the surface are required in the range of wavelengths comprised between 8 and 13 micrometers (atmospheric window). This constraint has motivated novel laboratory experiments. Collaborators : Daniel Beysens (PMMH), Laurent Royon (LIED), Tarik Bourouina (ESIEE). References : P.B. Bintein et al., Phys. Rev. Lett. 122, 098005 (2019) ; Trosseille et al., Int. J. Heat Mass Transfer 172, 121160 (2021).
Accès Salle des séminaires FAST-LPTMS (Bât. 530, salle C.120, 1er)