Analysis of empirical correlations of thermophysical properties of water suspensions of aluminum oxide nanoparticles

Here, we consider the empirical relationships presented earlier in the literature that describe the thermophysical properties of H2O + Al2O3 nanofluids, such as viscosity and heat conductivity coefficients. The main parameters affecting these properties of nanofluid are considered to be the volume fraction of particles ϕ, fluid temperature T, and particle size dp. The suitability of approximation formulas for calculating the viscosity and heat conductivity coefficients is determined by comparing the data calculated by these formulas with the experimental results. The behavior of the analytical curves of thermophysical coefficients is analyzed in the following ranges of influencing parameters: 0 < ϕ ≤ 0.1, 280 K ≤ T ≤ 360 K, 1 nm ≤ dp ≤ 100 nm. Estimates of the degree of dependence of calculation results on the values of these parameters are given. Conclusions on the qualitative and quantitative reliability of the correlation formulas proposed in the literature, as well as on the limits of their applicability in the ranges of variation of the influencing parameters are drawn.