Theoretical analyses and experiments on acoustic streaming field of ultrasonic motor driving fluid directly

Being quite different from the contact ultrasonic motors, in the non-contact ultrasonic motor driving fluid directly the rotor immersed in the fluid doesn´t contact with the stator directly. This motor solves many problems of the contact ultrasonic motor, such as shorter life expectancy and continuous running time, and becomes a new research direction in the field of the ultrasonic motor. This paper introduces the unique construction of this motor and the working mechanism. And then the course of transferring energy are discussed, in which the energy produced by the ultrasonic vibration is transferred to the rotor through the medium of fluid. It is revealed that the shearing Reynolds´ stress is the driving force of the fluid flow. This paper makes theoretical analyses on the acoustic streaming field and sets up the relationship between the acoustic streaming velocity and the rotating speed of the motor. After that, the basic operating characteristics of the motor and the relationship between the acoustic streaming velocity, the rotating speed and the driving frequency, the driving voltage, the fluid circumstances and the rotor radius are simulated with MATLAB program. At last, according to the results of simulations some experiments are made. By comparing the results between the experiments and the simulation, allowing for the effect of the fluid circumstances and the rotor radius on the rotating speed of the motor, the paper puts up discussions on the optimal working conditions of this motor.