This paper presents new numerical predictions for an electro-osmotic flow circulating in a slit microchannel when the influence of local temperature field caused at least by the Joule effect can alter the flow pattern. Taking into account that the Debye length depends on temperature , the above length should be used with caution because it appears in any electro-osmotic mathematical model. In fact, the dependence of the Debye length on the temperature field can generate additional temperature gradients along the microchannel, and the isothermal hypothesis is no longer valid, modifying the resulting governing equations. These terms are enough to change the electric potential and the flow field. Therefore, the Navier–Stokes equations, together with the energy, Poisson, and Ohmic current conservation equations, are solved using the finite element method. For this purpose, a dimensionless thermal parameter, , which measures the temperature deviations of a reference temperature, has been introduced. The numerical predictions show that the volumetric flow rate decreases in comparison with a uniforme Debye length, and strong induced pressure gradients are sensibly altered by the existence of this parameter.
Numerical Analysis for Temperature Changes in an Electro-Osmotic Flow in a Microchannel
Journal of Thermophysics and Heat Transfer ; 33 , 3 ; 663-672
2019-07-01
Article (Journal)
Electronic Resource
English
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