SINGLE- AND MULTI-CONSTITUENT CONDENSATION OF FLUIDS AND MIXTURES WITH VARYING PROPERTIES IN MICRO-CHANNELS

摘要

The relative magnitudes of the forces governing the transfer of heat, mass, and momentum during microscale condensation are fundamentally different from those in macroscale geometries, primarily due to the increasing importance of surface tension. A systematic series of experiments on condensation flow regimes, pressure drop, and heat transfer was conducted using innovative visualization and measurement techniques for condensation of synthetic and natural refrigerants and their azeotropic and zeotropic mixtures through micro-channels with a wide range of diameters (0.1 < D_H < 5 mm), shapes, and operating conditions. These experiments resulted in flow-regime-based heat transfer and pressure drop models with very good predictive capabilities for such micro-channel geometries.