Experimental study on the characteristics of bubble dynamics in pool boiling of water influenced by surface acoustic wave (SAW)

An experimental investigation on the boiling bubble dynamics of ultra-pure water was conducted by using surface acoustic wave (SAW). A peculiar bubble penetration phenomenon during water boiling was discovered in the absence of SAW excitation. SAW excitation was introduced by using a RF with amplitude ranging from 0 to 10Vpp, altered by a SAW filter. With SAW application in subcooled pool boiling (subcooling of 20 K), both bubble penetration and the bubble successivity behavior (bubbles appeared successively at the same nucleation site without waiting period) were observed, with an increase in the number of successive bubbles as SAW amplitude increased. The reason for this phenomenon is attributed to the disruption of the flow in the superheated fluid layer near the heating surface, and the promotion effect of the convection of the hot and cold fluids by SAW. This should be the main reason that SAW enhances boiling heat transfer. The finding is helpful to better understand the mechanism of boiling under acoustic waves and lay a foundation for its active boiling control.