Frictional pressure drop correlation for two-phase flows in mini and micro multi-channels

1029 frictional pressure drop data of two-phase flow in mini/micro multi-channels were collected from 11 literatures. This database included 8 working fluids: R134a, R22, R404a, FC-72, water, CO₂, R236fa and R245fa. The channel dimension ranged from 0.109 to 2.13 mm. Frictional pressure drop range of the database was from 5 to 150 kPa. The applicability of 11 existing correlations developed for mini/micro single channels to mini/micro multi-channels were evaluated with the multi-channel database. Among the existing correlations, the correlation of Lee-Mudawar predicted the database with the mean absolute percentage error (MAPE) of 35.3%, the correlations of Lee-Garimella and Sun-Mishima had MAPEs within 45.0%. In the process of new correlation development, the database was divided into three categories (namely, 1: gas laminar-liquid laminar, 2: gas turbulent-liquid laminar, 3: gas turbulent-liquid turbulent) in terms of liquid Reynolds number and gas Reynolds number, since gas laminar-liquid turbulent data did not exist in the literature. The newly developed correlation was formulated by a function of the two-phase Reynolds number, Re_tp, the two-phase viscosity number, N_μ, and the vapor quality, x. The correlation could predict the measured frictional pressure drop with the MAPE of 18.9%. The correlation demonstrated an excellent performance of the two-phase flow frictional pressure drop prediction in mini/micro multi-channels._tp