Mass flow rate correlation for two-phase flow of R218 through a capillary tube

This paper presents some experimental results of refrigerant two-phase flow through a capillary tube. The data was obtained for fluorinert refrigerant R218, which is used in some special vapor cooling circuits, e.g. in various particle detectors at the CERN international research centre. An analytical correlation for mass flow rate of R218 was prepared on the bases of dimensionless parameters derived from the Buckingham π-theorem. Two approaches were compared: (a) the conventional power law function and (b) correlation determined with the use of an artificial neural network. Measured data were also correlated with other mass flow rate correlations presented in literature.