Convective instability of a binary mixture with allowance for the Soret effect

1996 ◽  
Vol 31 (6) ◽  
pp. 933-937
Author(s):  
I. O. Keller
Keyword(s):  
Binary Mixture ◽  
Convective Instability ◽  
Soret Effect

Numerical Analysis of Ludwig-Soret Effect of One Binary Mixture and Two Ternary Mixtures in an Al2O3 Porous Cavity

2006 ◽  
Author(s):  
T. J. Jaber ◽  
M. Z. Saghir
Keyword(s):  
Porous Medium ◽  
Steady State ◽  
Numerical Analysis ◽  
Binary Mixture ◽  
Ternary Mixture ◽  
Soret Effect ◽  
Ternary Mixtures ◽  
Thermosolutal Convection ◽  
Left Wall ◽  
Porous Cavity

A cavity of 10 mm in width, 10 mm in height, and 32.1 mm in horizontal length filled with Al2O3 porous medium designed in Pau project to investigate thermal diffusion phenomena, or Ludwig-Soret effect. A lateral heating condition was applied with 10 °C at the left wall and 50 °C at the right wall. The thermosolutal convection of a binary mixture of water-ethanol at 75.0 MPa pressure, a ternary mixture with methane, n-butane, and n-dodecan at 35.0 MPa pressure, and a ternary mixture of n-dodecane, isobutylbenzene, and tetrahydonaphthalene at atmosphere pressure inside the Al2O3 porous medium cavity were numerically investigated. The thermal conductivity and the permeability of Al2O3 porous medium on the Ludwig-Soret effect were analyzed, the former had little influence, but the later had strong impact on the compositional separation at the steady state of thermosolutal convection, which were analyzed globally with separation ratio. The distributions of component mole fraction(s) on the horizontal and vertical lines in the center of the porous cavity were also shown to study the details of the compositional separation at the steady state of thermosolutal convection. Recommendations are made for the experimental design based on the results of numerical analysis

Dynamics of a binary mixture subjected to a temperature gradient and oscillatory forcing

2015 ◽  
Vol 767 ◽  
pp. 290-322 ◽  
Author(s):  
V. Shevtsova ◽  
Y. A. Gaponenko ◽  
V. Sechenyh ◽  
D. E. Melnikov ◽  
T. Lyubimova ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Binary Mixture ◽  
Stokes Equations ◽  
Soret Effect ◽  
Space Station ◽  
Three Dimensional ◽  
Microgravity Environment ◽  
Coupling Mechanism ◽  
Constant Frequency ◽  
Natural Time

AbstractWe examine the dynamics of a binary mixture in a cubic cell subjected to a temperature differential and oscillatory forcing. The Soret effect, which is negative in the present study, provides a coupling mechanism by which a temperature gradient establishes a concentration gradient in a mixture. We present the results of experiments that were performed on the International Space Station (ISS) and compare the observations with the results of direct numerical simulations. The evolution of temperature and concentration fields is investigated by optical digital interferometry. One advantage of the experimental technique is the observation of the fields along two perpendicular directions of the cell, allowing us to restore the three-dimensional field. Experimental evidence disproves speculations that the ISS microgravity environment always affects diffusion-controlled processes. Furthermore, we demonstrate that imposed vibrations with constant frequency and amplitude create slow mean flows and that they do influence the diffusion kinetics. The perturbation of the diffusive fields scales as the square of the vibrational velocity. In addition to calculations of the full three-dimensional Navier–Stokes equations, a two-time-scale computational methodology is used for situations in which the forcing period is very small compared to the natural time scales of the problem. The simulations show excellent agreement with experimental observations.

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