An Zou, Ashish Chanana, Amit Agrawal, Peter C. Wayner, Jr., Shalabh C. Maroo
Boiling, a dynamic and multiscale process, has been studied for over five decades; however, a comprehensive understanding of the process is still lacking. The bubble ebullition cycle, which involves nucleation, growth and departure, happens over a very short time-span (on the order of milliseconds) making it extremely challenging to study the near-surface interfacial characteristics of a single bubble. In this work, we create a steady-state vapor bubble that can remain stable for hours in a pool of subcooled water using a femtosecond laser source. The stability of the bubble allows us to measure its contact angle on hydrophilic and hydrophobic surfaces, and in both degassed and regular water. We further image and study the contact line region and the microlayer within the bubble, and find them to be sensitive to the presence of dissolved gases in the water. Using experimental data and finite-element-method based numerical simulations, we obtain permissible range of values of heat transfer coefficient and width of the evaporating layer in the contact line region, thus defining an upper limit to the heat transfer coefficient possible in nucleate boiling as well as in thin-film evaporation. This technique of creating and measuring fundamental characteristics of a stable vapor bubble will facilitate researchers towards unlocking the incomplete fundamental understanding of the boiling phenomenon.
, Chanana, A.
, Agrawal, A.
and Wayner, P.
Steady State Vapor Bubble in Pool Boiling, Scientific Reports, [online], https://doi.org/10.1038/srep20240, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=918948
(Accessed December 3, 2023)