Regularities of the themroelectrokinetic effect in colloidal tannin solution in the suppression of natural convection
Background. The study considers the thermoelectrokinetic effect, which belongs to a specific class of cross transport phenomena occurring under the simultaneous influence of three thermodynamic forces. The influence of natural convection on the steady-state fluid temperature and velocity fields f...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Penza State University Publishing House
2024-12-01
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| Series: | Известия высших учебных заведений. Поволжский регион: Физико-математические науки |
| Subjects: | |
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| Summary: | Background. The study considers the thermoelectrokinetic effect, which belongs
to a specific class of cross transport phenomena occurring under the simultaneous influence
of three thermodynamic forces. The influence of natural convection on the steady-state fluid
temperature and velocity fields formed in the presence of the thermoelectrokinetic effect
is evaluated. The method of suppression of natural convection in the measurement of thermoelectrokinetic
EMF is developed and the corresponding study in aqueous solution of
tannin is carried out. Materials and methods. Assessment of the influence of natural convection
on the temperature and velocity distributions of the liquid is carried out on the basis
of experimental measurements of its temperature field using a laboratory thermal imager
and calculations of the corresponding fields on the basis of numerical solution of the Navier-
Stokes, heat conduction, and continuity equations by the finite element method. Measurement
of thermoelectrokinetic EMF in colloidal tannin solution with suppression of free
convection is carried out using a modified experimental setup in which the direction of the
temperature gradient is reversed. Results. On the basis of numerical modeling and experimental
measurements, the temperature and velocity distributions of the liquid in the Ushaped
tube are obtained. The results of numerical calculations agree with the results of insitu
experiment. It is shown that in the classical formulation of the experiment to measure
thermoelectrokinetic EMF when heating the liquid in a U-shaped tube from below, it is not
possible to create a significant temperature drop, on which the value of thermoelectrokinetic
EMF depends. The thermoelectrokinetic EDS of colloidal tannin solution was measured
under conditions of suppressed convection. Under these conditions, the EMF reaches a significant
value. Conclusions. Thus, natural convection significantly affects the manifestation
of the thermoelectrokinetic effect in liquid electrically conducting media, and its suppression
contributes to the formation of higher temperature gradients. Due to this, the value of
thermoelectrokinetic EMF increases. |
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| ISSN: | 2072-3040 |