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Combined influences of viscous dissipation, non-uniform Joule heating and variable thermophysical properties on convective heat transfer in microtubes

Yavari, H ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1016/j.ijheatmasstransfer.2011.10.033
  3. Abstract:
  4. This study presents a comprehensive investigation on hydrodynamic and thermal transport properties of mixed electroosmotically and pressure driven flow in microtubes. Particular emphasis is given to investigating the combined consequences of viscous dissipation, non-uniform Joule heating, and variable thermophysical properties. Analytical solutions are obtained using the Debye-Hückel linearization and constant fluid properties assumption, while a numerical solution is presented for variable fluid properties and non-uniform distribution of Joule heating. The results indicate that, viscous heating effect is pronounced significantly when a favorable pressure gradient exists and cannot be neglected at low values of the dimensionless Debye-Hückel parameter. Moreover, uniform Joule heating assumption, even at low zeta potentials, may reduce the accuracy of the predicted thermal features considerably. The wall shear stress is found to be strongly dependent upon the zeta potential, which is underestimated by the Debye-Hückel linearization. Compared with the constant fluid properties case, decreasing electrical resistivity of the fluid by increasing temperature, amplifies the total energy generation due to the Joule heating and reduces the Nusselt number
  5. Keywords:
  6. Analytical solutions ; Convective heat transfer ; Electric double layer ; Electrical resistivity ; Favorable pressure gradients ; Fluid property ; Micro-tubes ; Non-uniform distribution ; Numerical solution ; Pressure-driven flows ; Temperature dependent properties ; Thermal features ; Thermal transport properties ; Total energy ; Variable fluid properties ; Variable thermo-physical properties ; Viscous dissipation ; Viscous heating effects ; Wall shear stress ; Electric conductivity ; Electroosmosis ; Fluids ; Forced convection ; Joule heating ; Linearization ; Nusselt number ; Thermodynamic properties ; Transport properties ; Viscous flow ; Zeta potential ; Heating
  7. Source: International Journal of Heat and Mass Transfer ; Volume 55, Issue 4 , January , 2012 , Pages 762-772 ; 00179310 (ISSN)
  8. URL: http://www.sciencedirect.com/science/article/pii/S0017931011006119