Viscous dissipative forced convection in thermal non-equilibrium nanofluid-saturated porous media embedded in microchannels

Ting T.W., Hung Y.M., Guo N., International Communications in Heat and Mass Transfer 57 (2014) 309–318, 2014

Under local thermal non-equilibriumand isoflux boundary conditions, the two-energy-equation model is employedto investigate the effect of viscous dissipation on the thermal characteristics of nanofluid flowthrough a porousmediumembedded in a microchannel. Analytical closed-form solutions of the two-dimensional temperature distributionsare obtained for the models with and without the viscous dissipation terms in the energy equation. Theanalysis emphasizes on the disparities induced by the viscous dissipation between the two models. The use of porousmedium is capable to enhance the thermal performance up to 53%. When the viscous dissipation effect isneglected, the thermal performance of nanofluid is overrated asmuch as 60%, sufficiently serious to trigger an attentionin the performance analysis. The heat transfer coefficient of nanofluid is found to be enhanced in the low-Reynolds-number flow regime but it declines in the high-Reynolds-number flow regime. By reducing the size ofnanoparticle, the thermal performance can be enhanced as much as 70%. Furthermore, the thermal performancecan be further augmented by increasing the channel aspect ratio as well as by increasing the thermal conductivityof the porous material. This study serves as a useful analytical tool for the design and performance characterizationof an integrated system incorporating the use of nanofluid and porous medium into a microchannel.

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