Ultrasonic effect

Ultrasonic effect: when the ultrasonic wave propagation in the medium, because of the ultrasonic wave interaction with the media, physical and chemical changes in the medium, to produce a series of mechanical, thermal, electromagnetics and chemical effects of ultrasound, including the following four kinds of effects:

And that is the mechanical effect. The mechanical action of ultrasonic can promote the emulsification of liquid, the liquefaction of gel and the dispersion of solid. When standing waves are formed in ultrasonic fluid medium, small particles suspended in the fluid are condensed at the wave joints due to the action of mechanical forces, and periodic accumulation is formed in space. Induced polarization and induced magnetization (see dielectric physics and magnetostriction) due to the mechanical action of ultrasonic waves in piezoelectric materials and magnetostrictive materials.

Parliamentary vacuumation. Ultrasonic waves can produce a large number of small bubbles when they act on liquids. One reason is that the local tensile stress in the liquid results in negative pressure. The decrease of pressure makes the gas originally dissolved in the liquid oversaturate and escape from the liquid into small bubbles. Another reason is that the strong tensile stress "tears" the liquid into a cavity, called cavitation. A liquid vapor or another gas dissolved in a liquid, perhaps even a vacuum. The small bubbles formed by cavitation will move, grow or burst with the vibration of the surrounding medium. When the surrounding liquid burst into the bubble, high temperature, high pressure and shock wave were produced. The internal friction associated with cavitation can form electric charge and generate luminescence in the bubble due to discharge. Ultrasonic treatment in liquid is mostly related to cavitation.

Student: heat transfer effect. Because of the high frequency and high energy of ultrasonic wave, it can generate significant thermal effect when absorbed by the medium.

Student: the chemical effects of theta. The action of ultrasound may induce or accelerate some chemical reactions. For example, hydrogen peroxide is produced from pure distilled water after ultrasonic treatment. Nitrite is produced in water with nitrogen dissolved by ultrasonic treatment. The dye solution will change color or fade after ultrasonic treatment. These phenomena are always accompanied by cavitation. Ultrasound can also accelerate the hydrolysis, decomposition and polymerization of many chemicals. Ultrasonic waves also have significant effects on photochemical and electrochemical processes. After ultrasonic treatment of various amino acids and other organic substances, the characteristic absorption band disappeared and showed uniform general absorption, indicating that cavitation changed the molecular structure.