Study on the behavior of wetted area right after liquid-wall contact in subcooled pool boiling

The behavior of rewetting on high superheated surface, focusing on an effect of liquid subcooling on wetted area and a contact angle during collapse of film boiling was investigated experimentally. In the experiments, a liquid jet from a nozzle was supplied on the superheated surface, made of a platinum wire, in the stable subcooled film boiling of ΔTsub = 15K, and then the wetted area was observed. The experimental results showed that the propagative collapse of the vapor film occurred when the local wall temperature was below near thermodynamic limit of liquid superheat. The measured angles between the liquid-vapor interfacial line and the heated wall corresponded to dynamic contact angle were close to the dynamic advancing contact-angles in room temperature even if the liquid is subcooled. (author)