Thermal delay of drop coalescence

• Main Authors: Geri, Michela (Contributor), Keshavarz, Bavand (Contributor), McKinley, Gareth H (Contributor), Bush, John W. M. (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Mathematics (Contributor), Massachusetts Institute of Technology. Department of Mechanical Engineering (Contributor)
• Format: Article
• Language: English
• Published: Cambridge University Press, 2017-11-16T15:24:16Z.
• Subjects: Article
• Online Access: Get fulltext

We present the results of a combined experimental and theoretical study of drop coalescence in the presence of an initial temperature difference 𝛥T[subscript 0] between a drop and a bath of the same liquid. We characterize experimentally the dependence of the residence time before coalescence on 𝛥T[subscript 0] for silicone oils with different viscosities. Delayed coalescence arises above a critical temperature difference 𝛥T[subscript c] that depends on the fluid viscosity: for 𝛥T[subscript 0] > 𝛥T[subscript c], the delay time increases 𝛥T[subscript 0] [superscript 2/3] as for all liquids examined. This observed dependence is rationalized theoretically through consideration of the thermocapillary flows generated within the drop, the bath and the intervening air layer.
National Science Foundation (U.S.) (Grant CMMI-1727565)
National Science Foundation (U.S.) (Grant DMS-1614043)