Experimental Investigation On The Thermal Conductivity And Viscosity Of Engine Coolant Based Alumina Nanofluids

In the present study, the alumina (Al(2)O(3)) nanoparticles (0.1 - 1.5 v%) with nominal diameter < 50 nm are stably dispersed in the HP "Kool Gard" car engine Coolant. Thermal conductivity ( k(nf)) and viscosity (mu(nf)) of the nanofluids are studied between 5 and 50C. Thermal conductivity of the nanofluid containing 1.5 vol. % Al(2)O(3) shows an enhancement of similar to 4.2% at 30C, which increases to similar to 4.5% at 50C. The observed enhancement of k(nf) is in excellent agreement with the model proposed by Prasher et al. Viscosity data reveals that the base fluid (coolant) is a Newtonian fluid at all temperatures, but displays non-Newtonian behavior with increase in particle volume fraction. All classical models under estimate the observed mu(nf) of the nanofluids. However, the model proposed recently by Masoumi et al, which is derived considering the Brownian motion of the nanoparticles, predicts the measured viscosity very well. An empirical correlation of the type log(mu(nf)) = A exp(BT) explains the temperature dependence of the viscosity of engine coolant based Al(2)O(3) nanofluid.