Experiments and updated model for two phase frictional pressure drop inside minichannels

The objective of this work is to investigate frictional pressure drop during adiabatic liquid–vapor flow inside minichannels. New experimental pressure drop data, relative to two-phase flow inside circular and noncircular horizontal channels with hydraulic diameters ranging from 0.96 mm to 2 mm, is presented. By analyzing this data the present authors updated the two-phase frictional pressure drop model presented by Cavallini et al. (2009) [16] and [17], developing a new equation to calculate the effects of surface roughness on the frictional pressure drop as a function of the liquid-only Reynolds number. The present updated model is validated against experimental data and compared with other available correlations.