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Viscous dissipation effects on thermal transport characteristics of combined pressure and electroosmotically driven flow in microchannels

Sadeghi, A ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1016/j.ijheatmasstransfer.2010.04.028
  3. Abstract:
  4. This study investigates the influence of viscous dissipation on thermal transport characteristics of the fully developed combined pressure and electroosmotically driven flow in parallel plate microchannels subject to uniform wall heat flux. Closed form expressions are obtained for the transverse distributions of electrical potential, velocity and temperature and also for Nusselt number. From the results it is realized that the Brinkman number has a significant effect on Nusselt number. Generally speaking, to increase Brinkman number is to decrease Nusselt number. Although the magnitude of Joule heating can affect Brinkman number dependency of Nusselt number, however the general trend remains unchanged. Depending on the value of flow parameters, a singularity may occur in Nusselt number values even in the absence of viscous heating, especially at great values of dimensionless Joule heating term. For a given value of Brinkman number, as dimensionless Debye-Huckel parameter increases, the effect of viscous heating increases. In this condition, as dimensionless Debye-Huckel parameter goes to infinity, the Nusselt number approaches zero, regardless of the magnitude of Joule heating. Furthermore, it is realized that the effect of Brinkman number on Nusselt number for pressure opposed flow is more notable than purely electroosmotic flow, while the opposite is true for pressure assisted flow
  5. Keywords:
  6. Laminar ; Microchannel ; Brinkman number ; Closed-form expression ; Convection ; Electrical potential ; Electroosmotic flow ; Flow parameters ; General trends ; Opposed flow ; Parallel plates ; Thermal transport ; Transverse distribution ; Uniform wall heat flux ; Viscous dissipation ; Viscous heating ; Electroosmosis ; Forced convection ; Heating ; Joule heating ; Microchannels ; Nusselt number ; Pressure effects ; Viscous flow ; Parallel flow
  7. Source: International Journal of Heat and Mass Transfer ; Volume 53, Issue 19-20 , 2010 , Pages 3782-3791 ; 00179310 (ISSN)
  8. URL: http://www.sciencedirect.com/science/article/pii/S0017931010002127