The Effects of Ultrasonic Vibration - Heat and Cavitation

High power ultrasound can have different effects on the process (sometimes even no useful effects), so it is important to understand the possible effects and their causes. These are the main (possible) impacts:

Fever

High energy mechanical vibration can be easily converted into heat through interface friction between different components or damping within the material (internal friction). This effect is utilized in welding, where the welding efficiency of plastics and metals is high because heat is generated exactly where it is needed - on the surface to be connected. This impact may also be a limitation - what we are talking about is the power loss caused by the conversion of energy into heat within and at the interface between transducers, boosters, and ultrasonic generators.

Cavitation

Whenever the environmental pressure decreases, the boiling point of the liquid also decreases. If the pressure drops enough, the liquid will begin to boil without heating (because the boiling point drops below room temperature). When this situation occurs within a small range, small bubbles are formed due to local pressure reduction - this is called cavitation. It may occur in liquids subjected to ultrasonic vibration or in low-pressure areas generated by other movements (such as ship propellers). Most of the effects are not caused by the formation of steam bubbles, but by their destruction. The low-pressure area is highly localized and constantly changing (for ultrasonic standing waves, the time between the lowest and highest pressures is usually 10 to 25 microseconds). Bubbles can only exist when the pressure is low - they are very unstable when the pressure is high, so they will collapse violently, instantly generating huge temperature and pressure. Of course, the collapse of each bubble occurs within a very small volume at the microscopic level, but under a strong and uniform ultrasonic field, millions of bubbles in the entire liquid will form and break down thousands of times per second, thus affecting the overall characteristics of the liquid. This effect has been utilized in sonochemistry and ultrasonic cleaning. Millions of uniform ultrasonic fields in the entire liquid will form and break thousands of times per second, so they can affect the overall characteristics of the liquid. This effect has been utilized in sonochemistry and ultrasonic cleaning. Millions of uniform ultrasonic fields in the entire liquid will form and break thousands of times per second, so they can affect the overall characteristics of the liquid. This effect has been utilized in sonochemistry and ultrasonic cleaning.