Experimental investigation on thermal and rheological properties of n-octadecane with dispersed TiO2 nanoparticles
2014 (English)In: International Communications in Heat and Mass Transfer, ISSN 0735-1933, Vol. 59, 68-74 p.Article in journal (Refereed) Published
In the present study, titanium (IV) oxide (TiO2) nanoparticles were dispersed in n-octadecane to fabricate phase change material (PCM) with enhanced properties and behavior. Thermal conductivity (TC) and viscosity of n-octadecane/TiO2 dispersions were experimentally investigated using transient plane source (TPS) technique and rotating coaxial cylindrical viscometer, respectively. The results showed that the TC of n-octadecane/TiO2 dispersion depends on temperature and nanoparticle loading. A non-monotonic behavior of TC enhancement in both solid and liquid phases was observed. In solid phase, the maximum TC enhancement occurred at 3 wt.% of nanoparticles. When the nanoparticle mass fraction was over 4% in liquid phase, the TC started to decrease. The rheological behavior of the n-octadecane/TiO2 samples indicated that dispersions with low nanoparticle mass fractions demonstrate Newtonian behavior, and for higher mass factions the shear-thinning behavior was observed. Shear stress vs. shear rate curves showed that the liquid phase of PCM behaves like a Bingham plastic fluid for mass fraction greater than 1%. As expected, the effective viscosity could be influenced by temperature. At the shear rate of 48.92 s(-1) for 3 wt.% nanoparticles, the effective viscosity decreased by 26.8% while temperature increased from 35 degrees C to 55 degrees C. For the investigated n-octadecane/TiO2 dispersions, new thermophysical correlations are proposed for predicting TC and rheological properties.
Place, publisher, year, edition, pages
2014. Vol. 59, 68-74 p.
n-Octadecane, PCM, TiO2 nanoparticle, Thermal conductivity, Rheological properties
IdentifiersURN: urn:nbn:se:kth:diva-159628DOI: 10.1016/j.icheatmasstransfer.2014.10.016ISI: 000347500800010ScopusID: 2-s2.0-84910094051OAI: oai:DiVA.org:kth-159628DiVA: diva2:787153
QC 201502092015-02-092015-02-052015-02-09Bibliographically approved