Heat Transfer Enhancement in Subcooled Boiling with Ultrasonic Field

Subcooled quasi-pool boiling of water is performed at liquid subcooling of 15K ∼ 30K for a flat heating surface of 10mm in diameter in the ultrasonic field. Microbubble emission boiling is generated at higher liquid subcooling than 25K without ultrasonic activation and the heat flux increases higher than the ordinary critical heat flux. At liquid subcooling of 20K in the ultrasonic field, microbubble emission boiling is generated and the heat flux increases as high as the case of high liquid subcooling. The ultrasonic wave accelerates the instability of bubble interface and is strongly effective for heat transfer enhancement with microbubble emission boiling at liquid subcooling of 20K in the experiments.