Abstract
The non-Newtonian nanofluid flow becomes increasingly important in enhancing the thermal management efficiency of microscale devices and in promoting the exploration of the thermal-electric energy conversion process. The effect of streaming potential and viscous dissipation in the heat transfer characteristics of power-law nanofluid electrokinetic flow in a rectangular microchannel has been investigated to assist in the development of an energy harvesting system. The electroviscous effect caused by the streaming potential influences the hydrodynamical and thermal characteristics of flow. With the change in constitutive behavior of power-law nanofluid, the viscous dissipation effect is considered. The Poisson–Boltzmann equation, the modified Cauchy momentum equation, and the energy equation were solved. The temperature and heat transfer rate were analytically expressed for Newtonian nanofluid and numerically obtained for power-law nanofluid. The interactive influence of streaming potential, viscous dissipation, and hydrodynamical features of power-law nanofluid on the heat transfer characteristics were studied. The presence of streaming potential tends to reduce the dimensionless bulk mean temperature. The introduction of nanoparticles augments dimensionless temperature difference between channel wall and bulk flow, which decreases the heat transfer rate. The shear thinning nanofluid is more sensitive to the above effects. The temperature is a weak function of the flow behavior index.
Highlights
The great advancement of microfabrication technologies has led to the wide application of lab-on-chip-based microsystems for chemical and biomedical analysis [1], and heat sinks for electronic cooling [2]
Since non-Newtonian fluids have been manipulated in micropumps and microreactors, the heat transfer characteristics of electroosmotic flow (EOF) for power-law nanofluid in a parallel plate microchannel were investigated by analytically solving the one-dimensional momentum equation and energy equation [33]
The third term in the left hand side (LHS) of Equation (5) represents the resistance force arising from the presence of streaming potential, namely the measurement of the streaming potential effect, where Es is the strength of induced electric field in electric double layer (EDL)
Summary
The great advancement of microfabrication technologies has led to the wide application of lab-on-chip-based microsystems for chemical and biomedical analysis [1], and heat sinks for electronic cooling [2]. A comprehensive analysis shows that in addition to the investigation on EOF in [23], the study on the thermal transport characteristics of power-law fluid flow including Newtonian flow is mainly confined to parallel microchannels [24,25,26,27] and microcapillaries [9,20]. Since non-Newtonian fluids have been manipulated in micropumps and microreactors, the heat transfer characteristics of EOF for power-law nanofluid in a parallel plate microchannel were investigated by analytically solving the one-dimensional momentum equation and energy equation [33]. An up-to-date literature review shows that the thermal behaviors of electrokinetic flow with the interactive effects of streaming potential, nanoparticles and power-law constitutive relation have been rarely investigated.
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