Power ultrasonic technology and its application
The application of ultrasonic technology and its products can be divided into two categories, one is with a weaker ultrasound to realize information acquisition and processing, this kind of technology products in radar and sonar, ultrasonic diagnosis, ultrasonic flaw detection, ultrasonic detection and so on; the other is using strong ultrasonic power, ultrasonic, material or to change the focus of the human body the state, quality or performance with its energy, the technology and application of product with ultrasonic cleaning, ultrasonic grinding, ultrasonic atomizing, ultrasonic stirring, ultrasonic welding, ultrasonic treatment is sound chemistry etc..
Power ultrasound is using ultrasonic energy to change the material structure, status, function or accelerate these changes, power ultrasonic treatment technology can lead to or enhance mechanical and physical, chemical and biological processes, improve the process quality and efficiency, to other processing technology is difficult to achieve the effect of. Power ultrasound has been widely used in industry, agriculture, biology, medicine and health, environmental protection and other sectors of the national economy and national defense industry, can be used for cleaning, crushing, atomization, emulsification, homogenization, extraction, condensation; can be used in electroplating, tin, dipping, filtration, drying can be used to accelerate; welding, cutting, grinding and polishing; chemical reactions, can be used for oil extraction; can be used for the treatment of disease, surgery. In addition, in the past ten years, the rapid development of new technologies, such as ultrasonic vibration cutting, ultrasonic fatigue testing, ultrasonic levitation, ultrasonic motor, and so on.
The effect of power ultrasound is the core application of ultrasonic cavitation, ultrasonic cavitation effect called (Ultrasonic Cavitation) usually refers to the tiny bubbles existing in the liquid (nucleus) under ultrasonic irradiation is activated, oscillation showed growth, shrinkage and collapse of a series of dynamic processes. As early as 100 years ago, the first British destroyer launching test, found the screw propeller caused severe vibration phenomenon in the water, Thornycro and Barnaby indicated that because of the propeller in the water rotation produced a large number of bubbles, the bubbles in the water under pressure until the contraction immediately broken. This is the first description of the physical nature of cavitation (cavitation) phenomena in history. In Britain, after improved design several times, but they could not get rid of the vibration problems, then officially invited master classic acoustics Lord Rayleigh to study the problem, in 1917, Rayleigh published a report entitled "the collapse of spherical cavity in liquid pressure" this significant research paper, laid the foundation for the subsequent study of cavitation theory.
Theoretical and experimental studies have confirmed that the cavitation process enables the acoustic energy focus (focus), accompanied by the collapse of a cavitation bubble moment, minimal space in the liquid in the highly concentrated energy release, the formation of unusual high temperature (>5000K), high voltage (>5 * 107pa), strong shock wave and jet extreme physical conditions etc..
