Author(s): , , , , ,

Keywords: , , , , , , , , , , , , ,

Abstract: The thermal and rheological properties of n-octadecane, a phase change material, with dispersed TiO2 nanoparticles were investigated at varying temperatures. The properties were investigated in both the solid and liquid phases, with varying mass fractions of TiO2 nanoparticles. The thermal conductivity was found to be enhanced in all of the composite samples when compared to the thermal conductivity of pure n-octadecane, and the maximum enhancement occurred at 3 wt. % TiO2 in the solid phase, and 4 wt. % in the liquid phase. The maximum enhancement was approximately 5% in both phases. The results of the rheological testing that was performed on the composite samples indicated that increasing the mass fraction of TiO2 above 2% resulted in a shift from Newtonian to non-Newtonian behavior. A predictive model for estimating the thermal conductivity of this type of composite phase change material was produced by least-squares fitting. The Bingham plastic model was evaluated as a model for predicting the rheological properties of these materials. Both of the models were in good agreement with the experimental data.

Reference: International Communications in Heat and Mass Transfer 59 (2014) 68–74

DOI: 10.1016/j.icheatmasstransfer.2014.10.016