Analytical solutions for thermo-fluidic transport in electroosmotic flow through rough microtubes

• Surface roughness effects on fully developed electroosmotic flow and heat transfer in circular microtubes are studied.
• Analytical solutions based are presented for a representative scenario.
• It is revealed that higher values of the corrugation number and relative roughness give rise to lower Nusselt numbers.

The limitations of the microfabrication technology do not allow producing perfectly smooth microchannels. Hence, exploring the influences of roughness on transport phenomena in microtubes is of great importance to the scientific community. In the present work, consideration is given toward the corrugated roughness effects on fully developed electroosmotic flow and heat transfer in circular microtubes. Analytical solutions based on perturbation technique are presented for the problem assuming a low zeta potential under the constant heat flux boundary condition of the first kind. It is revealed that higher values of the corrugation number and relative roughness give rise to smaller Nusselt numbers. Since the same is true for the mean velocity, one may conclude that the roughness effects on the hydrodynamic and thermal features of electroosmotic flow are negative. Further, the Nusselt number is found to be a decreasing function of the Joule heating rate and an increasing function of the dimensionless Debye-Hückel parameter.