G061022 Marangoni convection near a vapor bubble under temperature gradient in using alcohol aqueous solutions

2013 ◽  
Vol 2013 (0) ◽  
pp. _G061022-1-_G061022-5
Author(s):  
Takuya OJIRO ◽  
Kentaro KAWAI ◽  
Naoki ONO
Keyword(s):  
Temperature Gradient ◽  
Aqueous Solutions ◽  
Vapor Bubble ◽  
Marangoni Convection

Surface Deformation and Thermal Convection in Electrostatically-Positioned Droplets Under Microgravity

1999 ◽  
Author(s):  
Suping Song ◽  
Ben Q. Li
Keyword(s):  
Surface Tension ◽  
Temperature Gradient ◽  
Laser Heating ◽  
Surface Deformation ◽  
Marangoni Convection ◽  
Stokes Equations ◽  
Energy Balance Equation ◽  
Droplet Surface ◽  
Fundamental Study ◽  
Recirculating Flow

Abstract Electrostatically positioned droplets are very useful for the fundamental study of solidification phenomena and the measurement of thermal physical properties. This paper descries a numerical analysis of surface deformation and surface tension driven flows in electrostatically positioned droplets in microgravity. The analysis is based on a fully coupled boundary element and finite element solution of the Maxwell equations, the Navier-Stokes equations and the energy balance equation. Results show that an applied electrostatic field results in a nonuniform electric stress distribution along the droplet surface, which, combined with surface tension, causes the droplet to deform into an ellipsoidal shape in microgravity. Laser heating induces a non-uniform temperature distribution in the droplet, which in turn produces Marangoni convection in the droplet. It is found that the viscous stress contribution to the deformation is small for a majority of cases. Also, a higher temperature gradient produces a stronger Marangoni convection in droplets with higher melting points that require more laser power. The internal recirculating flow may be reduced by more uniform laser heating. During the undercooling of the droplet, both temperature and fluid flow fields evolve in time such that the temperature gradient and the tangential velocities along the droplet surface subside in magnitude and reverse their directions.

Effect of Marangoni Convection on InSb Single Crystal Growth by Horizontal Bridgman Method

2001 ◽  
Vol 692 ◽  
Author(s):  
K. Kodera ◽  
A. Kinoshita ◽  
K. Arafune ◽  
Y. Nakae ◽  
A. Hirata
Keyword(s):  
Crystal Growth ◽  
Binary System ◽  
Temperature Gradient ◽  
Single Crystal ◽  
Grown Crystal ◽  
Marangoni Convection ◽  
Single Crystal Growth ◽  
Control Technique ◽  
Growth System

AbstractIt is necessary to clarify the effect of Marangoni convection on single crystal growth from a melt in order to improve the quality of the grown crystal. Particularly, the deviation of crystalmelt (C-M) interface from a planar shape is a major problem because it may deteriorate the quality of the grown crystal. In this paper, we investigated the effect of thermal and solutal Marangoni convection on C-M interface shape in an In-Sb binary system by the horizontal Bridgman (HB) method. The C-M interface concavity strongly depends on the cooling rate and the temperature gradient under uniform concentration distribution conditions in the melt. A large concavity was observed at low cooling rates and high temperature gradient conditions. The concavity was found to be caused by thermal Marangoni convection, by taking Péclet number into account. Then, we varied the composition of the In-Sb binary system to induce solutal Marangoni convection intentionally. The C-M interface was kept planar in case solutal Marangoni convection occurred in the direction opposite to the thermal one. Therefore, we believe that the utilization of solutal Marangoni convection will be a new control technique to make the C-M interface planar for the HB system. From these results, it was clarified that Marangoni convection plays a significant role in the HB crystal growth system.

Magnetohydrodynamics Thermocapillary Marangoni Convection Heat Transfer of Power-Law Fluids Driven by Temperature Gradient

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Yanhai Lin ◽  
Liancun Zheng ◽  
Xinxin Zhang
Keyword(s):  
Heat Transfer ◽  
Temperature Gradient ◽  
Differential Equations ◽  
Power Law ◽  
Numerical Solutions ◽  
Marangoni Convection ◽  
Convection Heat Transfer ◽  
Temperature Fields ◽  
Convection Heat ◽  
Power Law Fluids

This paper presents an investigation for magnetohydrodynamics (MHD) thermocapillary Marangoni convection heat transfer of an electrically conducting power-law fluid driven by temperature gradient. The surface tension is assumed to vary linearly with temperature and the effects of power-law viscosity on temperature fields are taken into account by modified Fourier law for power-law fluids (proposed by Pop). The governing partial differential equations are converted into ordinary differential equations and numerical solutions are presented. The effects of the Hartmann number, the power-law index and the Marangoni number on the velocity and temperature fields are discussed and analyzed in detail.

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