Effect of Axial Conduction and Variable Properties on Two- Dimensional Conjugate Heat Transfer of Al۲O۳-EG/Water Mixture Nanofluid in Microchannel

Conjugate heat transfer of a nanofluid containing Al۲O۳ nanoparticles dispersed in a mixture of ۶۰% ethylene glycol and ۴۰% water by mass (۶۰:۴۰ EG/W) in a two dimensional microchannel has been solved numerically. The effect of axial conduction in both solid and liquid regions has been considered in a range of Reynolds numbers in laminar regime. The utilized nanofluid models are capable of considering variation of thermal conductivity and dynamic viscosity with temperature. The results show that using nanoparticles with higher thermal conductivities will enhance heat transfer characteristics of the channel. Comparing the nanofluid with pure mixture revealed that adding nanoparticles will decrease conduction number which is a scale of axial conduction. Also, it was found that considering variable properties will cause severe changes to the Nusselt number distribution especially for low Reynolds numbers.