Abstract
In this study, experimental tests are carried out to investigate the heat transfer performance under pool natural convection and subcooled boiling conditions, and ultrasonic vibration is introduced to evaluate the possible enhancement performance. The heat flux of the heater set at 7.7×〖10〗^3-1.7×〖10〗^5 W/m2.Ultrasonic vibration operated with a frequency of 28 and 40 kHz and a power of 90-150W. The water temperature were set at 30, 40, and 50℃. Through this study, the height effect, water temperature effect, ultrasonic frequency effect, and ultrasonic effect were studied for the heat transfer enhancement under ultrasonic vibration. An experimental database of pool-subcooled heat transfer from single phase natural convection to sub-cooled nucleate boiling is established, and the heat transfer enhancement performance is identified and determined under with and without ultrasonic vibration conditions. In the present test conditions, the heat transfer enhancement ratio can be up to 3 (or enhancement of 300%). This study can provide clear experimental evidences and better understanding about the influences of ultrasonic waves on heat transfer performance in pool conditions, and the empirical correlation can be useful for future safety design of reactor core and fuel storage.