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    Mixed electroosmotically and pressure-driven flow with temperature- dependent properties

    , Article Journal of Thermophysics and Heat Transfer ; Volume 25, Issue 3 , Sep , 2011 , Pages 432-442 ; 08878722 (ISSN) Sadeghi, A ; Yavari, H ; Saidi, M. H ; Chakraborty, S ; Sharif University of Technology
    2011
    Abstract
    The present work reports the outcome of a comprehensive parametric study on mixed electroosmotically and pressure-driven flow in slit microchannels with constant wall heat fluxes. Special attention is given to disclose the applicability ranges of usual assumptions in simplified analyses. The governing equations for fully developed conditions are first made dimensionless and then solved by means of an implicit finite difference method. The results reveal that the assumption of constant thermophysical properties does not leadto significant errors in practical applications. Although the Debye-Huckel linearization may successfully be used to evaluate velocity profiles up to the zeta potentials... 

    Hydrodynamic and thermal characteristics of combined electroosmotic and pressure driven flow in a microannulus

    , Article Journal of Heat Transfer ; Volume 134, Issue 10 , 2012 ; 00221481 (ISSN) Yavari, H ; Sadeghi, A ; Saidi, M. H ; Sharif University of Technology
    ASME  2012
    Abstract
    The present study considers both the hydrodynamic and thermal characteristics of combined electroosmotic and pressure driven flow in a microannulus. Analytical solutions are presented using the Debye-Hückel linearization along with the uniform Joule heating and negligible viscous dissipation assumptions, whereas exact results are achieved numerically. Here, the range of validity for the Debye-Hückel linearization is found to be about two times of that for a parallel plate microchannel. Accordingly, this linearization may successfully be used to evaluate the potential and velocity distributions up to the zeta potentials of 100 mV, provided that the dimensionless Debye-Hückel parameter is... 

    Electroosmotic flow of viscoelastic fluids through a slit microchannel with a step change in wall temperature

    , Article Journal of Heat Transfer ; Volume 135, Issue 2 , 2013 ; 00221481 (ISSN) Sadeghi, A ; Veisi, H ; Saidi, M. H ; Asghar Mozafari, A ; Sharif University of Technology
    2013
    Abstract
    Thermally developing electroosmotically generated flow of two viscoelastic fluids, namely the PTT and FENE-P models, through a slit microchannel is considered. Both the viscous dissipation and Joule heating effects are taken into account and a step change in wall temperature is considered to represent physically conceivable thermal entrance conditions. Expressions for the dimensionless temperature and Nusselt number in the form of infinite series are presented. In general, the resultant eigenvalue problem is solved numerically; nevertheless, an analytical solution is presented for the regions close to the entrance. A parametric study reveals that increasing amounts of the Peclet number... 

    Thermally developing electroosmotic flow of power-law fluids in a parallel plate microchannel

    , Article International Journal of Thermal Sciences ; Volume 61 , 2012 , Pages 106-117 ; 12900729 (ISSN) Sadeghi, A ; Saidi, M.H ; Veisi, H ; Fattahi, M ; Sharif University of Technology
    2012
    Abstract
    The present investigation considers the thermally developing electroosmotic flow of power-law fluids through a parallel plate microchannel. Both the viscous dissipation and Joule heating effects are taken into account and a step change in wall temperature is considered to represent physically conceivable thermal entrance conditions. Expressions for the dimensionless temperature and Nusselt number in the form of infinite series are presented. In general, the resultant eigenvalue problem is solved numerically; nevertheless, an analytical solution is presented for the regions close to the entrance. A parametric study reveals that increasing amounts of the Peclet number result in higher wall... 

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

    , Article International Journal of Heat and Mass Transfer ; Volume 55, Issue 4 , January , 2012 , Pages 762-772 ; 00179310 (ISSN) Yavari, H ; Sadeghi, A ; Saidi, M. H ; Chakraborty, S ; Sharif University of Technology
    Abstract
    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...