IWNET12
IWNET12
Macroscopic convective phenomena in non-uniformly heated liquid mix-
tures
Vitaly A. Demin1, Alexander F. Glukhov2
1 Theoretical Physics Department, Perm State University, Perm, Russia
2 General Physics Department, Perm State University, Perm, Russia
Abstract
Thermal non-stationary convection of binary and multi-component liquid mixtures in thin channels of dierent
congurations was investigated experimentally and theoretically. Connected channels and Hele-Shaw cell with
boundaries of high heat conductivity were used as working cavities. Experiments were held with the following
mixtures: 1) carbon tetrachloride (CCl4) in decane (C10H22), 2) aqueous solutions of sodium sulfate (Na2SO4),
3) water-ethanol mixtures, 4) magnetic uid (stable colloidal suspension of ultra-ne ferromagnetic particles in
kerosene).
It was shown that over the threshold of convection specic "op-over" oscillatory ows with very large period
take place in the cases of binary molecular mixtures with normal thermodiusion (1, 2) and magnetic uids
with dierent concentration of particles (4-12%). Direct numerical simulation on the base of hydrodynamics
equations conrmed to results of experiments. On the other hand stationary convective ow was settled in
molecular mixtures with anomalous thermodiusion (3) that also was veried by the numerical calculations.
Physical mechanisms were suggested to explain observed phenomena. According to our point of view the complex
"op-over" oscillatory regimes in binary molecular mixtures with normal thermodiusion are determined by
division of components in horizontal plane when the liquid moves predominantly along vertical heat-conducting
boundaries of a cavity [1].
Analogously to molecular mixtures periodic change of ow direction in magnetic uid is explained by molecular
thermodiusion of kerosene components and depends on week eect of particles sedimentation. During numerical
modeling there was no reason to take into account thermodiusion of particles to describe the experiments with
magnetic colloids.
References
References
[1] Glukhov A.F., Demin V.A., and Putin G.F. Binary-Mixture Convection in Connected Channels Heated from
Below. Fluid Dynamics, (2007), Vol. 42, No. 2, pp. 160-169.
[2] Glukhov A.F., Demin V.A., Putin G.F. Separation of Mixtures and Mass Transfer in Connected Channels.
J. Technical Physics Letters, (2008), Vol. 34, No. 9, pp. 747-749.
E-mail: demin@psu.ru

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