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Article
Interfacial temperature measurements, high-speed visualization and finite-element simulations of droplet impact and evaporation on a solid surface
International Journal of Heat and Mass Transfer (2010)
  • Rajneesh Bhardwaj, Columbia University
  • Jon P. Longtin
  • Daniel Attinger, Columbia University
Abstract
The objective of this work is to investigate the coupling of fluid dynamics, heat transfer and mass transfer during the impact and evaporation of droplets on a heated solid substrate. A laser-based thermoreflectance method is used to measure the temperature at the solid–liquid interface, with a time and space resolution of 100 μs and 20 μm, respectively. Isopropanol droplets with micro- and nanoliter volumes are considered. A finite-element model is used to simulate the transient fluid dynamics and heat transfer during the droplet deposition process, considering the dynamics of wetting as well as Laplace and Marangoni stresses on the liquid–gas boundary. For cases involving evaporation, the diffusion of vapor in the atmosphere is solved numerically, providing an exact boundary condition for the evaporative flux at the droplet–air interface. High-speed visualizations are performed to provide matching parameters for the wetting model used in the simulations. Numerical and experimental results are compared for the transient heat transfer and the fluid dynamics involved during the droplet deposition. Our results describe and explain temperature oscillations at the drop–substrate interface during the early stages of impact. For the first time, a full simulation of the impact and subsequent evaporation of a drop on a heated surface is performed, and excellent agreement is found with the experimental results. Our results also shed light on the influence of wetting on the heat transfer during evaporation.
Keywords
  • droplet impact,
  • droplet evaporation,
  • interfacial heat transfer,
  • temperature measurement,
  • laser temperature measurement,
  • high-speed visualization,
  • numerical simulation
Publication Date
September, 2010
Publisher Statement
NOTICE: this is the author’s version of a work that was accepted for publication in International Journald of Heat Mass Transfer. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Journal of Heat Mass Transfer, [53, 19-20, (2010)] doi:10.1016/j.ijheatmasstransfer.2010.04.024
Citation Information
Rajneesh Bhardwaj, Jon P. Longtin and Daniel Attinger. "Interfacial temperature measurements, high-speed visualization and finite-element simulations of droplet impact and evaporation on a solid surface" International Journal of Heat and Mass Transfer Vol. 53 Iss. 19-20 (2010)
Available at: http://works.bepress.com/daniel_attinger/13/