Mathematical modeling and experimental study on solid–liquid suspension separation in ultrasonic standing wave field

A new method of removing waste chips is proposed by focusing on the key factors affecting the processing quality and efficiency of high energy beams. Firstly, a mathematical model has been established to provide the theoretical basis for the separation of solid–liquid suspension under ultrasonic standing wave. Secondly, the distribution of sound field with and without droplet has been simulated. Thirdly, the deformation and movement of droplets are simulated and tested. It is found that the sound pressure around the droplet is greater than the sound pressure in the droplet, which can promote the separation of droplets and provide theoretical support for the ultrasonic suspension separation of droplet; under the interaction of acoustic radiation force, surface tension, adhesion, and static pressure, the droplet is deformed so that the gas fluid around the droplet is concentrated in the center to achieve droplet separation, and the droplet just as a flat ball with a central sag is stably suspended in the acoustic wave node.

Gravity-Aided Ultrasonic Separation of Nanoparticles from Liquid Using Macro-Scale Separator

Acoustophoresis is the technology to separate the microparticles and cells from suspending fluid. This research focuses on the separation of nanoparticles from water by using macro-scale fluidic separator which works based on gravity-aided ultrasonic standing wave technology. Titanium dioxide particles of 40 nm diameter were concentrated by the combination of ultrasonic standing wave field at 2.2 MHz and gravity-aided sedimentation. The purpose of this study is to investigate the performance of gravity-aided ultrasonic particle to concentrate nanoparticles. It was found that the separation efficiency is 83% at a flow rate of 0.1 mL/min. FEM simulations were also conducted to evaluate characteristics of variation of acoustic energy inside the fluidic channel. Results indicate that nanoparticles can be concentrated using gravity-aided ultrasonic standing wave field, however optimization of the design of the fluidic channel is required for increasing throughput of the separator.