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Theoretical model of droplets motions on solid surface with radial wettable and evaporation rate gradients

Yang, Yanjie LU ; Wu, Zan LU ; Chen, Xiaoqian ; Sundén, Bengt LU and Huang, Yiyong (2018) ASME 2018 International Mechanical Engineering Congress and Exposition, IMECE 2018 8A-2018.
Abstract

Wettability gradient in radial direction and evaporation rate gradient can cause droplet motion on a solid surface. Here a theoretical model is proposed. Besides, an equation of droplet velocity is derived on a solid surface. We consider the wettability and evaporation rate gradients are mainly caused by the chemical composition and surface roughness, only along the radial direction. Surface tension at the liquid-vapor interface is constant as it is assumed that the temperature does not change during the whole process. Thus, Marangoni effect induced by the liquid-vapor surface tension gradient is neglected. Besides, as droplet size is set as less than the capillary length (Formula presented.), the gravity effect is ignored as well. The... (More)

Wettability gradient in radial direction and evaporation rate gradient can cause droplet motion on a solid surface. Here a theoretical model is proposed. Besides, an equation of droplet velocity is derived on a solid surface. We consider the wettability and evaporation rate gradients are mainly caused by the chemical composition and surface roughness, only along the radial direction. Surface tension at the liquid-vapor interface is constant as it is assumed that the temperature does not change during the whole process. Thus, Marangoni effect induced by the liquid-vapor surface tension gradient is neglected. Besides, as droplet size is set as less than the capillary length (Formula presented.), the gravity effect is ignored as well. The velocity at the droplet center on a gradient surface along the radial direction is half of that along the x-direction. With the simulation of water droplet, the center velocity decreases with time and the droplet radius increases at the beginning part and then decreases.

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author
; ; ; and
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
host publication
Heat Transfer and Thermal Engineering
volume
8A-2018
publisher
American Society Of Mechanical Engineers (ASME)
conference name
ASME 2018 International Mechanical Engineering Congress and Exposition, IMECE 2018
conference location
Pittsburgh, United States
conference dates
2018-11-09 - 2018-11-15
external identifiers
  • scopus:85063164402
ISBN
9780791852118
DOI
10.1115/IMECE2018-87890
language
English
LU publication?
yes
id
0eeecdfc-6102-4b1b-a997-accaed02e22e
date added to LUP
2019-04-05 14:53:16
date last changed
2020-05-26 16:47:59
@inproceedings{0eeecdfc-6102-4b1b-a997-accaed02e22e,
  abstract     = {<p>Wettability gradient in radial direction and evaporation rate gradient can cause droplet motion on a solid surface. Here a theoretical model is proposed. Besides, an equation of droplet velocity is derived on a solid surface. We consider the wettability and evaporation rate gradients are mainly caused by the chemical composition and surface roughness, only along the radial direction. Surface tension at the liquid-vapor interface is constant as it is assumed that the temperature does not change during the whole process. Thus, Marangoni effect induced by the liquid-vapor surface tension gradient is neglected. Besides, as droplet size is set as less than the capillary length (Formula presented.), the gravity effect is ignored as well. The velocity at the droplet center on a gradient surface along the radial direction is half of that along the x-direction. With the simulation of water droplet, the center velocity decreases with time and the droplet radius increases at the beginning part and then decreases.</p>},
  author       = {Yang, Yanjie and Wu, Zan and Chen, Xiaoqian and Sundén, Bengt and Huang, Yiyong},
  booktitle    = {Heat Transfer and Thermal Engineering},
  isbn         = {9780791852118},
  language     = {eng},
  month        = {01},
  publisher    = {American Society Of Mechanical Engineers (ASME)},
  title        = {Theoretical model of droplets motions on solid surface with radial wettable and evaporation rate gradients},
  url          = {http://dx.doi.org/10.1115/IMECE2018-87890},
  doi          = {10.1115/IMECE2018-87890},
  volume       = {8A-2018},
  year         = {2018},
}