Thermal conductivity and viscosity of Al₂O₃ nanofluid based on car engine coolant

Abstract

Various suspensions containing Al2O3 nanoparticles (<50 nm) in a car engine coolant have been prepared using oleic acid as the surfactant and are tested to be stable for more than 80 days. Thermal conductivity and viscosity of the nanofluids have been investigated both as a function of concentration of Al2O3 nanoparticles as well as temperature between 10 and 80 °C. The prepared nanofluid, containing only 0.035 volume fraction of Al2O3 nanoparticles, displays a fairly higher thermal conductivity than the base fluid and a maximum enhancement (k nf/k bf) of ∼10.41% is observed at room temperature. The thermal conductivity enhancement of the Al2O3 nanofluid based on engine coolant is proportional to the volume fraction of Al2O3. The volume fraction and temperature dependence of the thermal conductivity of the studied nanofluids present excellent correspondence with the model proposed by Prasher et al (2005 Phys. Rev. Lett. 94 025901), which takes into account the role of translational Brownian motion, interparticle potential and convection in fluid arising from Brownian movement of nanoparticles for thermal energy transfer in nanofluids. Viscosity data demonstrate transition from Newtonian characteristics for the base fluid to non-Newtonian behaviour with increasing content of Al2O3 in the base fluid (coolant). The data also show that the viscosity increases with an increase in concentration and decreases with an increase in temperature. An empirical correlation of the type log(μnf) = A exp(−BT) explains the observed temperature dependence of the measured viscosity of Al2O3 nanofluid based on car engine coolant. We further confirm that Al2O3 nanoparticle concentration dependence of the viscosity of nanofluids is very well predicted on the basis of a recently reported theoretical model (Masoumi et al 2009 J. Phys. D: Appl. Phys. 42 055501), which considers Brownian motion of nanoparticles in the nanofluid.

Shear History Effect on the Viscosity of Carbon Nanotubes Water-based Nanofluid

“…The first one is based on the physical or chemical treatment of the nanoparticles, in particular for carbon nanotubes [28] and the use of dispersing agents such as polymers. The dispersing of nanoparticles can also be obtained from mechanical methods such as sonication [2,4,17,21], ultrasonication [3,[5][6][7]12], homogenization [6,12] and high stirring [3,5,14]. The dispersion and the stability of the nanofluids are mainly obtained by gathering some of the previous mentioned methods.…”

Experimental investigations of the viscosity of nanofluids at low temperatures

“…They reported that viscosity decreases exponentially with the increase of temperature. Kole et al [18] investigated Al 2 O 3 -car engine coolant nanofluid and found that the Brownian motion of the nanoparticles in the fluid plays an important role in understanding the viscosity of nanofluids.…”

On the Nanofluids Application in the Automotive Radiator to Reach the Enhanced Thermal Performance: A Review

“…In Table 1, one can see their results on an enhancement of radiator thermal effectiveness versus flow rate during nanofluids with different volume concentrations implementation. An experimental study on nanofluids viscosity in car radiator was carried out by Kole and Dey (2010). They used alumina nanoparticles dispersed in water and stabilized by oleic acid.…”