Local Heat Transfer Coefficient of Flow Boiling in Microchannels With Artificial Reentrant Cavities

Flow boiling in parallel microchannels with structured reentrant cavities was experimental studied. Flow patterns, boiling inceptions and heat transfer coefficients were obtained and studied for G = 83 kg/m²-s to G = 303 kg/m²-s and heat fluxes up to 643 W/cm². The heat transfer coefficient-mass velocity and quality relations had been analyzed to identify boiling mechanism. Comparisons of the performance of the enhanced and plain-wall microchannels had also been made. The microchannels with reentrant cavities were shown to promote nucleation of bubbles and to support significantly better reproducibility and uniformity of bubble generation.