Empirical Modeling and Flow-Regime Analysis of Condensation Heat Transfer in Micro/Minichannels

Over 2,000 condensation heat-transfer data points from 29 sources in micro/minichannels were compiled for empirical modeling and flow analysis. The new condensation heat transfer correlation fits 87% of the data within ±50%. The correlation was also successfully tested using available flow-regime-specific data, indicating the equations’ universal applicability across all flow regimes. A sensitivity analysis revealed that buoyancy and gravitational forces were dominant during condensation in micro/mini channels. A flow analysis based on widely reported flow maps showed that condensing flows in micro/minichannels were predominantly in the transition and annular (wavy and smooth) regimes. Confinement or surface-tension effects were detected even in tubes with diameters over 1.5 mm. Apart from these few exceptions, in general, macrotube effects were dominant in most minichannels with diameters greater than 200 μm.