Prediction of condensation pressure drop inside herringbone microfin tubes

A generalized prediction correlation of condensation pressure drop inside herringbone microfin tubes has been proposed which includes the new empirical correlation of two-phase frictional multiplier and author’s previously proposed correlation of single-phase friction factor for herringbone microfin tubes. Three existing correlations and the newly proposed correlation of condensation pressure drop for herringbone microfin tubes have been compared with the available experimental data of five herringbone microfin tubes during condensation of R410A. From the results of overall root-mean-square (r.m.s.) deviations of relative residuals of condensation pressure drop for all tubes, proposed correlation shows best performance. Proposed correlation can also predict other experimental data of two-phase pressure drop of R410A during adiabatic two-phase flow and previously measured data of condensation pressure drop of R22 within ±20% which are not used to develop the proposed correlation.