Simulation And Experiment Research On Ultrasonic Standing Wave Levitation And Transportation Stability

Ultrasonic standing wave levitation as a promising experimental technique, can provides the non-contact environment which has been widely used in the materials fabrication, biochemical analysis and sample manipulation. In addition, due t o avoid the surface restriction and pollution, ultrasonic levitated droplets is an ideal system study droplet fluid-dynamics, micro-reaction, fluid-fusion, fluid-evaporation, etc. Based on the current research on ultrasonic standing wave levitation a nd transportation stability is rarely reported, this paper discusses the factors that influence the stability of the levitation and transportation in both simulation and experimental method. Specific work is given as follows:Firstly, this paper analyzes the stability mechanism of standing wav e levitation and transportation. Established an equivalent spring oscillator model to represent standing wave sound field; deduce parameters such as acoustic levitation force, acoustic elastic recovery coefficient which affect the stability of the ultrasonic standing wave levitation and transportation, and discussed the intrinsic relationship between the levitated object vibration and the acoustic parameters such as transducer amplitude, sound pressure, acoustic time averaged potential, density of the levitated object, acoustic elastic restitution coefficient; based on transducer array levitator explains the ultrasonic standing wave transportation mechanism, and puts forward some factors that influence the stability of the transportation.Secondly, this paper study the levitation stability in the single axis acoustic levitator. Establish the finite element parametric model, predict the th ree and four layer resonance mode of acoustic field, simulation the elastic recovery coefficient of the levitation point in the acoustic field; put forward a new experiment method combined computer vision Hough circle detection and FFT analysis to research the vibration of levitated object in the acoustic field; do some stability experiments in different acoustic power, different levitated object density, different levitated position, different distance between the radiating surface and reflecting surface, prove the correctness of acoustic spring oscillator model.Finally, based on the transducer array, this paper study the transportation stability. Using finite element simulation analysis, research on 1 × 3 transducer array levitation capability, get the appropriate distance between the radiating surface and reflecting surface in transportation; focusing on some cavity parameters(the gap between transducer, the distance between the radiating surface and reflecting surface, the length of the radiating surface) witch have influence on transportation stability; analysis 1 × 5 transducer array opposite transportation process stability in four amplitude modulation function, the acoustic pressure fluctuation and the maximum acoustic levitation force fluctuation is studied; build a transducer array platform for transportation experiment, Several experiments is carried out, such as the levitation position in 1 × 3 transducer array, the levitation position at different transducer gap, the target oscillation at different distance between the radiating surface and reflecting surface, the opposite transportation in 1 × 5 transducer array.