Parameter survey of the performance of a noncontact ultrasonic motor

Acoustic streaming was proposed to drive rotary motors, where a gas layer exists between the stator and the rotor. With numerical simulations for this kind of noncontact ultrasonic motors, the influences of the parameters of the air flow on the performance of the motors are calculated and analyzed. The results show that the replacement of invariant viscosity by the temperature-dependent viscosity decreases the rotor velocity by similar to 11%. Heat conduction is found to play a trivial role. It is also revealed that the rotor velocity increases more and more rapidly as the thickness of the air gap becomes smaller and smaller. Most importantly, we demonstrated that this kind of motor is very stable, and the rotor velocity is insensitive to the working temperature of the environment. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3238251]