Effect of temperature on the effective thermal conductivity of n-tetradecane-based nanofluids containing copper nanoparticles

Nanofluids were prepared by dispersing Cu nanoparticles (∼20   nm) in n-tetradecane by a two-step method. The effective thermal conductivity was measured for various nanoparticle volume fractions (0.0001–0.02) and temperatures (306.22–452.66   K). The experimental data compares well with the Jang and Choi model. The thermal conductivity enhancement was lower above 391.06   K than for that between 306.22 and 360.77   K. The interfacial thermal resistance increased with increasing temperature. The effective thermal conductivity enhancement was greater than that obtained with a more viscous fluid as the base media at 452.66   K because of nanoconvection induced by nanoparticle Brownian motion at high temperature.