Generalized adiabatic pressure drop correlations in evaporative micro/mini-channels

Existing database in literature on the adiabatic two-phase frictional pressure drop in evaporative micro/mini-channels were reviewed. The collected database contains 769 data points, covering 12 fluids, for a wide range of operational conditions and channel dimensions. The whole database was analyzed using five existing correlations to verify their respective accuracies. The importance of the Bond number, which relates the nominal bubble dimension or capillary parameter with the channel size, was revealed. A particular trend was observed with the Bond number that distinguished the entire database into three ranges. Using the Bond number, improved correlations of adiabatic two-phase pressure drop were established for small Bond number regions. The newly proposed correlations can predict the database well for the region where BoRel0.5 ⩽ 200.