**ABSTRACT**

In terms of heat dissipation, nanofluids with strong thermal conductivity are becoming more and more common, attracting more and more research and attention to date.In this study, Al2O3-H2O nanofluids were studied using molecular dynamics simulations and model parameterization. The dynamic viscosity distribution patterns were obtained at various temperatures(290K~360K), nanoparticle volume fractions(1.24%~6.2%), and particle sphericity(0.69~1.0), and an efficient ternary second-order polynomial viscosity prediction model was proposed on the basis of these results.The findings demonstrate the model's goodness-of-fit with a coefficient of determination over 0.96 and a root mean square error under 0.05, as well as its high predictive ability with a maximum relative error between simulated and predicted values under 9%. Using this viscosity prediction model, a subsequent parametric sensitivity study showsthat the volume fraction had the most significant impact on viscosity, exhibiting not just a second order effect but also an interacting effect with temperature and sphericity. The relative nanofluid viscosity, which is the ratio of nanofluid viscosity to aqueous base fluid viscosity, exhibits a convex parabolic growth at constant temperature and sphericity and increases more quickly at the same volume fraction the higher the temperature. The viscosity of the nanofluid increases by up to 34% when the volume fraction is equal to 6.28% and the particle sphericity is equal to 1.An efficient viscosity prediction model makes it easier to control important variables to reduce energy consumption during flow and increase its capacity to dissipate heat.

**KEYWORDS**

PAPER SUBMITTED: 2022-09-26

PAPER REVISED: 2023-02-13

PAPER ACCEPTED: 2023-02-20

PUBLISHED ONLINE: 2023-04-22

**THERMAL SCIENCE** YEAR

**2023**, VOLUME

**27**, ISSUE

**Issue 5**, PAGES [4223 - 4234]

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