Droplet evaporation on a structured surface: The role of near wall vortexes in heat and mass transfer

S. Y. Misyura, G. V. Kuznetsov, R. S. Volkov, V. S. Morozov

Research output: Contribution to journalArticle

Abstract

Experimental studies on the evaporation of a drop located on a horizontal hot wall with cavities of different diameters of 0.5–2.5 mm were carried out. The wall temperature Tw was constant (74 °C and 83 °C). The evaporation behavior on a structured surface was compared with that on a smooth wall. Instantaneous velocity profiles have been obtained over a single cavity and in the vicinity of several cavities using the Micro Particle Image Velocity method (Micro PIV). It has been established that a hotter liquid is periodically ejected from the cavity, which increases convection inside the drop. The strongest intensification of mass transfer is specific for the largest cavities with a diameter of 2.5 mm. The behavior of the droplet evaporation on a smooth wall coincides with that on a structured surface with a cavity diameter of 0.5 mm. Until now, there have been no data that would link the convection in the drop with the vortexes in the cavity at non-isothermal evaporation and at high heat fluxes. The strongest influence of cavities is manifested in the initial period of evaporation, when a cold drop is placed on a hot wall. Over time, the evaporation rate on a structured wall approaches evaporation on a smooth (unstructured) surface. The article considers the influence of several key factors on the convection in a drop.

Original languageEnglish
Article number119126
JournalInternational Journal of Heat and Mass Transfer
Volume148
DOIs
Publication statusPublished - Feb 2020

Keywords

  • Cavity
  • Droplet evaporation
  • Evaporation rate
  • Free convection
  • Structured surface

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

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