Abstract
The friction factor and heat transfer of Giesekus-fluid-based nanofluids in a pipe flow were studied in the ranges of 0.5 ≤ Reynolds number (Re) ≤ 500, 1 ≤ Weissenberg number (Wi) ≤ 8, 0.5% ≤ particle volume concentration (Φ) ≤ 3.0%, 0 ≤ viscosity ratio (β0) ≤ 1, and 0 ≤ mobility parameter (α) ≤ 0.5. Our numerical method was validated by comparing the results with available ones in the literature. The effects of Wi, Φ, β0, Re, and α on the relative friction factor (Cf/CfNew), Nusselt number (Nu), and ratio (PECnf/PECf) of energy performance evaluation criterion for Giesekus-fluid-based nanofluids to those for Giesekus fluid were discussed. The results showed that the values for the Cf/CfNew and Nu of Giesekus-fluid-based nanofluids were larger than those for Newtonian fluid-based nanofluids and those for pure Giesekus fluid. The values for Cf/CfNew increased with increasing Φ and Re, but they increased with decreasing β0 and α. As Wi increased, the values of Cf/CfNew first increased and then decreased. The values of Nu and PECnf/PECf were enhanced with increasing Wi, Φ, Re, and α, but with decreasing β0. It is more effective to use Giesekus-fluid-based nanofluids to improve heat transfer with the conditions of a larger Wi, Φ, Re, and α and a smaller β0. Finally, the correlation formula for PECnf/PECf as a function of Wi, Φ, β0, Re, and α was derived.