Viscosity of refrigerants and other working fluids from residual entropy scaling
Ian H. Bell, Arno R. Laesecke
The dynamic modeling of thermal systems and their components has gained an increased importance in recent years. Viscosity is one of the transport properties of fluids that are required for detailed analyses of system components, including compressors, heat exchangers, and other devices. The current state-of-the-art for the transport properties of a number of working fluids of relevance are based on extended corresponding states, which is extremely computationally expensive due to the conformal state solver. More computationally efficient models for transport properties of pure fluids with reasonable accuracy are required. In this work we apply a modified scaling of viscosity with residual entropy in a manner analogous to that proposed by Rosenfeld. We consider the viscosity-entropy scaling for a reference fluid (refrigerant R124), and demonstrate that the viscosity for many other refrigerants scales with residual entropy in a similar manner. Finally, we use a corresponding- states formalism with one adjustable parameter to obtain the viscosity in a non-iterative fashion for a number of refrigerants. The viscosities of the studied fluids are represented within average absolute relative deviations of 10 %. The evaluation of the liquid viscosity from this formulation can be up to 40 times faster than evaluating the viscosity from extended corresponding states.
16th International Refrigeration and Air Conditioning Conference at Purdue, July 11-14, 2016
and Laesecke, A.
Viscosity of refrigerants and other working fluids from residual entropy scaling, 16th International Refrigeration and Air Conditioning Conference at Purdue, July 11-14, 2016, West Lafayette, IN, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=920655
(Accessed June 9, 2023)