A numerical model for the thermocapillary flow and heat transfer in a thin liquid film on a microstructured wall

2007 ◽  
Vol 17 (3) ◽  
pp. 247-262 ◽  
Author(s):  
A. Alexeev ◽  
T. Gambaryan‐Roisman ◽  
P. Stephan
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Liquid Film ◽  
Thin Liquid Film ◽  
Thermocapillary Flow ◽  
Flow And Heat Transfer

Inverse-thermocapillary evaporation in a thin liquid film of self-rewetting fluid

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Elaine Lim ◽  
Tze Cheng Kueh ◽  
Yew Mun Hung
Keyword(s):  
Heat Transfer ◽  
Surface Tension ◽  
Liquid Film ◽  
Temperature Region ◽  
Thin Liquid Film ◽  
Thermocapillary Flow ◽  
Working Fluid ◽  
Surface Tension Gradient ◽  
Thermocapillary Effect ◽  
Content Type

Purpose The present study aims to investigate the inverse-thermocapillary effect in an evaporating thin liquid film of self-rewetting fluid, which is a dilute aqueous solution (DAS) of long-chain alcohol. Design/methodology/approach A long-wave evolution model modified for self-rewetting fluids is used to study the inverse thermocapillary characteristics of an evaporating thin liquid film. The flow attributed to the inverse thermocapillary action is manifested through the streamline plots and the evaporative heat transfer characteristics are quantified and analyzed. Findings The thermocapillary flow induced by the negative surface tension gradient drives the liquid from a low-surface-tension (high temperature) region to a high-surface-tension (low temperature) region, retarding the liquid circulation and the evaporation strength. The positive surface tension gradients of self-rewetting fluids induce inverse-thermocapillary flow. The results of different working fluids, namely, water, heptanol and DAS of heptanol, are examined and compared. The thermocapillary characteristic of a working fluid is significantly affected by the sign of the surface tension gradient and the inverse effect is profound at a high excess temperature. The inverse thermocapillary effect significantly enhances evaporation rates. Originality/value The current investigation on the inverse thermocapillary effect in a self-rewetting evaporating thin film liquid has not been attempted previously. This study provides insights on the hydrodynamic and thermal characteristics of thermocapillary evaporation of self-rewetting liquid, which give rise to significant thermal enhancement of the microscale phase-change heat transfer devices.

Numerical Study for the Flow and Heat Transfer in a Thin Liquid Film Over an Unsteady Stretching Sheet with Variable Fluid Properties in the Presence of Thermal Radiation

2012 ◽  
Vol 28 (2) ◽  
pp. 291-297 ◽  
Author(s):  
I-C. Liu ◽  
A. M. Megahed
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Differential Equations ◽  
Thermal Radiation ◽  
Liquid Film ◽  
Stretching Sheet ◽  
Numerical Study ◽  
Thin Liquid Film ◽  
Unsteady Stretching Sheet ◽  
Flow And Heat Transfer

AbstractIn this paper, the effect of thermal radiation, variable viscosity and variable thermal conductivity on the flow and heat transfer of a thin liquid film over an unsteady stretching sheet is analyzed. The continuity, momentum and energy equations, which are coupled nonlinear partial differential equations, are reduced to a set of two non-linear ordinary differential equations, before being solved numerically. Results for the skin-friction coefficient, local Nusselt number, velocity profiles as well as temperature profiles are presented for different values of the governing parameters. It is found that increasing the viscosity parameter leads to a rise in the velocity near the surface of the sheet and a fall in the temperature. Furthermore, it is shown that the temperature increases due to an increase in the values of the thermal conductivity parameter and the thermal radiation parameter, while it decreases with an increase of the Prandtl number.

MHD flow and heat transfer in a non-Newtonian liquid film over an unsteady stretching sheet with variable fluid properties

2009 ◽  
Vol 87 (10) ◽  
pp. 1065-1071 ◽  
Author(s):  
Mostafa A.A. Mahmoud ◽  
Ahmed M. Megahed
Keyword(s):  
Heat Transfer ◽  
Liquid Film ◽  
Stretching Sheet ◽  
Variable Viscosity ◽  
Thin Liquid Film ◽  
Mhd Flow ◽  
Physical Parameters ◽  
Local Skin ◽  
Unsteady Stretching Sheet ◽  
Flow And Heat Transfer

The present paper is concerned with the study of variable viscosity and variable thermal conductivity on the flow and heat transfer of an electrically conducting non-Newtonian power-law fluid within a thin liquid film over an unsteady stretching sheet in the presence of a transverse magnetic field. The transformed system of nonlinear ordinary differential equations describing the problem is solved numerically. The effects of various parameters on the velocity and temperature profiles are shown through graphs and discussed. The values of the local skin-friction coefficient and the local Nusselt number for different values of physical parameters are presented through tables.

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