The thermal conductivity, viscosity, and cloud points of bentonite nanofluids with n-pentadecane as the base fluid

Thermal conductivity data are reported for nanofluids consisting of 1-4 volume % bentonite particles dispersed in n-pentadecane, potentially for oil-based drilling fluids. The measurements were conducted at temperatures between 298 K and 393 K. The thermal conductivity increases with increasing nano particle concentration, attaining a maximum enhancement of 16.6% in nanofluids containing 4 volume % bentonite. The temperature behavior of the thermal conductivity in nanofluid follows closely that of the base fluid, i.e. n-pentadecane. The effect of temperature on the viscosity of nanofluids was also investigated. The viscosity decreases with increasing temperature at a constant nano particle volume fraction. As expected, the viscosity also increases with increasing nano particle concentration. Cloud point temperatures of nanofluids were measured as a function of particle volume fraction. Cloud point temperatures increases with increasing particle concentration, attaining a maximum increase of 3.10% in nanofluids containing 4 volume % bentonite. Correlations for the thermal conductivity and viscosity are presented for bentonite/n-pentadecane nanofluids with acceptable accuracy. (C) 2019 Elsevier B.V. All rights reserved.