A general correlation for the frictional pressure drop during condensation in mini/micro and macro channels

A general nonlinear equation for estimating the frictional pressure drop during condensation of fluids in different mini/micro and macro channels was obtained using the genetic programming (GP). The developed model is similar to that of the Lockhart and Martinelli [1] model. For developing the new correlation, 7328 data points were collected from 35 sources, which cover a wide range of fluids, channel geometries, diameters, mass fluxes, and saturation temperatures for single-port and multi-port channels. The newly developed correlation for the two-phase flow predicted a wide range of conditions with an average absolute relative deviation (AARD) of 22.92%. The same database was used for the evaluation of the available empirical correlations. Their deviations were significantly higher than that of the new correlation. (C) 2020 Elsevier Ltd. All rights reserved.