The cavitation effect is that when the ultrasonic wave is propagating in the medium, the average distance of the molecule in the liquid varies with the vibration of the molecule, and the cavitation occurs when it exceeds the critical molecular spacing that keeps the liquid active. Ultrasonic cavitation effect is divided into 2 forms, steady cavitation (frequency 200~500khz, sound intensity <10w/cm) and transient cavitation (frequency ~100khz, sound intensity >10w/cm). Steady-state cavitation occurs under the action of lower sound intensity, the bubble expands slowly in the negative pressure half cycle, slowly shrinks in the positive pressure half cycle but does not rupture, and bubbles do periodic, non-linear oscillation motions. Steady-state cavitation bubble life is relatively long, the degree of cavitation is more moderate, the impact on the medium microenvironment is small; transient cavitation adiabatic contraction to the expansion of instantaneous, bubble can produce high temperature and pressure, damage cell structure or broken cells, so that the enzyme inactivation. The transient cavitation degree is intense, which causes the medium to form a plurality of local extreme physical and chemical environment, which has great influence on the medium microenvironment. Transient cavitation accelerates certain chemical reactions in this special energy form and initiates new pathways for certain reactions.
The High-frequency oscillation signal emitted by the ultrasonic generator, by converting the transducer into a high-frequency mechanical vibration and propagating to the medium, the ultrasonic wave Biamishang forward in the solution, and when the pressure of the sound wave reaches a certain atmospheric pressure, it produces tens of thousands of tiny bubbles that form and grow in the negative pressure zone where the ultrasound is transmitted vertically, And in the positive pressure area quickly closed. This phenomenon is called ultrasonic "cavitation effect". Cavitation can be used to promote chemical reactions, crushing liquid suspended solids, manufacturing emulsion, killing bacteria, or cleaning parts. Ultrasonic homogeneous is the use of ultrasonic in the liquid cavitation effect to achieve uniform dispersion of materials. The homogeneous effect of ultrasonic wave is not only related to power density, but also to ultrasonic frequency and time of ultrasonic processing. Under the appropriate ultrasonic frequency, the minimum power density can be used to achieve the ideal dispersion effect.