Infrared Thermography Investigation of an Evaporating Water/Oil Meniscus in Confined Geometry.

To simulate the heat and mass transfer in real heterogeneous systems, such as metal-production processes and lubrication, the point-contact condition with the formation of narrowly confined liquid film and its surrounding meniscus was constructed to study the classical microchannel boiling problem in this work. Specifically, the evaporation and diffusion of the superheated water meniscus and water/oil droplet in the point-contact geometry were investigated. The emphasis is put on the influence of the contact-line transport behaviors on nucleation and bubble dynamics in the confined meniscus. The observations suggested that superheat is the necessary condition for bubble formation, and enough vapor supply is the necessary condition for bubble growth in the confined liquid. The oil film could significantly inhibit the evaporation and diffusion of water molecules in the superheat geometry. The water/oil droplet can exist for a long time even in the hot contact region, which could have sustained damages to the mechanical system suffering from water pollution. This work is of great significance to better understand the damage mechanism of water pollution to the mechanical system.