A better prediction for calculating the viscosity. The Percus–Yevick approximation at triplet level

In this work, we have intended to calculate the viscosity of some real fluids by using integral equation method. For this purpose, we have obtained the radial distribution function of the hard-sphere system at the triplet level. In this regard, we have solved the Ornstein–Zernike (OZ) equation by using the Triezenberg–Zwanzwig (TZ) equation and Percus–Yevick (PY) closure approximation. Since the method corresponds to using the PY closure at the triplet level, we designate our results as PY3. Then, we have used the radial distribution function obtained at the triplet level to calculate the viscosity of several real fluids. According to the results, we have found that the viscosity obtained by the PY3 method is in fair agreement with available results.