Power Ultrasound Technology and Application Introduction
Ultrasonic technology and its application products can be divided into two categories, one is to use weak ultrasound to achieve information collection and processing, such technology products have radar, sonar, ultrasonic diagnosis, ultrasonic flaw detection, ultrasonic testing, etc.; One type uses strong ultrasound, ie power ultrasound, to change the state, nature or performance of materials or human lesions with its energy. This type of technology and its application products include ultrasonic cleaning, ultrasonic pulverization, ultrasonic atomization humidification, ultrasonic stirring. , ultrasonic welding, ultrasonic treatment and even sonochemistry.
Power ultrasound is the process of using ultrasound energy to change the structure, state, function, or acceleration of these materials. Power ultrasonic processing can initiate or enhance mechanical, physical, chemical, biological processes, improve the quality and efficiency of these processes, and achieve other The effect that processing technology is difficult to achieve. Power ultrasound has been widely used in various sectors of the national economy such as industry, agriculture, biology, medical and health, environmental protection, and the national defense industry. It can be used for cleaning, crushing, atomizing, emulsifying, homogenizing, extracting, and coagulating; Used for electroplating, antimony tin, impregnation, filtration, accelerated drying; can be used for welding, cutting, grinding, polishing; can be used for chemical reaction, oil exploitation; can be used for disease treatment, surgery. In addition, in the past decade, new interdisciplinary disciplines such as ultrasonic vibration cutting, ultrasonic fatigue testing, ultrasonic suspension, and ultrasonic motor have developed rapidly, and some industrial applications have emerged.
The core function of power ultrasound is the application of ultrasonic cavitation effect. The so-called ultrasonic cavitation effect (Ultrasonic Cavitation) usually refers to the oscillation and growth of tiny bubbles (cavitation nucleus) present in the liquid activated by ultrasonic waves. , a series of dynamic processes such as shrinkage and collapse. As early as 100 years ago, when the British first destroyer launched the water test, it was found that the propeller propeller caused severe vibration in the water. Thornycro and Barnaby research showed that a large number of bubbles were generated due to the rotation of the propeller in the water. Under the pressure of water, it shrinks and then breaks down. This is the first time in history that the physical nature of cavitation has been described. After the United Kingdom, after several improvements in design, but can not get rid of the vibration problem, he officially invited the classic acoustic master Lord Rayleigh to study this problem. In 1917, Rayleigh published the title "The pressure generated by the collapse of the spherical cavity in the liquid." This clear research paper laid the foundation for the study of post-cavitation theory.
Theoretical and experimental studies have confirmed that the cavitation process can concentrate (focus) the sound field energy, and with the instantaneous collapse of the cavitation bubble, it releases its highly concentrated energy in a very small space in the liquid, forming an unusually high temperature ( >5000K), high pressure (>5×107pa), strong shock wave, jet and other extreme physical conditions.