General correlation of two-phase frictional pressure drop inside smooth tubes

Calculating a two-phase pressure drop is required in many fields. A general and accurate correlation is still needed, although numerous studies of frictional pressure drop correlations have been conducted. Therefore, a wide range of experimental data points were collected on the two-phase pressure drop of smooth tubes, 2012 points, covering 16 refrigerants with tube diameters ranging from 1.88 to 12 mm. The experimental data points were compared and evaluated with nine widely used correlations and models. The results show that the (Kim and Mudawar in Journal of Int J Heat Mass Transf 55:3246-3261, 2012) correlation gives the best prediction, followed by the Wang et al. (Exp Therm Fluid Sci 15:395–405, 1997) correlation and Friedel (European Two-Phase Flow Group Meeting, Ispra, Italy, 1979) correlation with mean deviations of 26.94%, 27.26% and 29.76%, respectively. A general two-phase frictional pressure drop correlation is proposed. The proposed correlation is validated against the database and compared with other correlations. The proposed correlation agrees better with the database than the others, with an absolute mean deviation of 19.84%.