Analysis Of Two Different Action Characteristics Used By Ultrasonic Homogenizer

The ultrasonic homogenizer uses the cavitation and other physical effects of ultrasonic waves in the liquid to achieve the homogenization effect. Ultrasound is a propagation process of mechanical vibration in a medium. It has the characteristics of bunching, orientation, reflection, and transmission. It mainly produces two forms of vibration in the medium, namely transverse waves and longitudinal waves. The former can only be generated in solids, and the latter can be produced in solid, liquid, and gas.

Cavitation means that under the action of ultrasonic waves, the liquid produces cavities or small bubbles in the weaker places, and the small bubbles pulsate with the ultrasonic waves. Ultrasonic cavitation also produces a strong mechanical action that produces a fast jet or acoustic rush near the solid interface, creating a powerful shock wave in the liquid. The physical effect means that ultrasonic waves can form effective agitation and flow in the liquid to destroy the structure of the medium and smash the particles in the liquid, mainly due to the collision between the liquids, the microphase flow, and the shock wave.

Theoretically, a bursting cavitation bubble would generate pressures in excess of 10,000 psi and temperatures of 20,000°F (11,000°C), and the shock wave would rapidly radiate outward the moment it burst. The energy released by a single cavitation bubble is very small, but millions of cavitation bubbles burst at the same time every second. The cumulative effect will be very strong, and the strong impact force will peel off the dirt on the surface of the workpiece. , which is characteristic of all ultrasonic cleaning.

If the ultrasonic energy is large enough, cavitation will occur everywhere in the cleaning fluid, so ultrasonic waves can effectively clean tiny cracks and holes. Cavitation also promotes chemical reactions and accelerates the dissolution of the surface film. However, only when the liquid pressure in a certain area is lower than the gas pressure in the bubble will cavitation occur in this area, so this condition can be satisfied when the ultrasonic amplitude generated by the transducer is large enough. The small power required to generate cavitation is called the cavitation critical point. Different liquids have different cavitation critical points, so the ultrasonic energy must exceed this critical point to achieve the cleaning effect. That is, only when the energy exceeds the critical point can cavitation bubbles be generated for ultrasonic cleaning.