Viscosity of Polar Fluids in the Critical Regions from the Perturbed Virial Expansion

In this work, viscosity of polar fluids such as R125, R22, and R134 in the critical regions are calculated theoretically. For this purpose, the perturbed virial expansion is first applied to calculate the fluid critical points. Then, using these points, the critical viscosity is obtained. In this work, two potential models like the dipolar hard-sphere and Stockmayer potential have been used. According to the obtained results, it is found that: i) the critical temperatures, pressures and viscosities obtained by using the Stockmayer potential are better than the dipolar hard- sphere potential. ii) the critical densities obtained by using the both models, are equal.