TY - JOUR ID - 71900 TI - The Effect of Viscous Dissipation and Variable Properties on Nanofluids Flow in Two Dimensional Microchannels JO - International Journal of Engineering JA - IJE LA - en SN - 1025-2495 AU - Ranjbar, Abolfazl AU - Ramiar, Abas AD - Control, Babol Noshirvani university of Technology AD - , Babol Noshirvani university of technology Y1 - 2011 PY - 2011 VL - 24 IS - 2 SP - 131 EP - 142 KW - Nanofluids KW - Heat transfer enhancement KW - Nusselt Number KW - Critical Reynolds Number DO - N2 - Laminar two dimensional forced convective heat transfer of Al2O3 –water nanofluid in a horizontal microchannel has been studied numerically, considering axial conduction, viscous dissipation and variable properties effects. The existing criteria in the literature for considering viscous dissipation in energy equation are compared for different cases and the most proper one is applied for the rest of the paper. The results showed that nanoparticles enhance heat transfer characteristics of the channel and on contrast, viscous dissipation causes the Nusselt number and friction factor to decrease. The viscous dissipation effect may be emphasized by increasing Reynolds number and decreased by raising the exerted heat flux. Also, it was found that there is a critical Reynolds number below which the average Nusselt number of the nanofluid changes unusually with Reynolds number as a result of variable properties effect. UR - https://www.ije.ir/article_71900.html L1 - https://www.ije.ir/article_71900_d5e6018909b1e4275b0b6d5229a3052d.pdf ER -