Theory and experimental verification of spiral flow tube-type valveless piezoelectric pump with gyroscopic effect

Valveless piezoelectric pump has low-cost and easy miniaturization characteristics, and its important development trend is multi-function integration. The current paper reports a new phenomenon that the flow in a spiral tube element is sensitive to the element attitude caused by the Coriolis force, and that a valveless piezoelectric pump is designed by applying this phenomenon. The valveless piezoelectric pump has both the actuator function of fluid transfer and the sensor function, which can obtain the angular velocity variation when its attitude changes. First, the present paper analyzes the principle of the pump and the flow characteristics in the tube. The calculation formula for the pump flow is also obtained. Second, the relationship between pump attitude and flow is identified, which theoretically verifies the gyroscopic effect of the pump. Finally, a pump is fabricated for experimental testing of the relationship between pump attitude and flow. Experimental results show that when Archimedes spiral theta = 4 pi is selected for the tube design, the pump is most efficient, and the pressure differential between pump inlet and outlet is 29 mm H2O, which achieves a one-way mean flow. On the other hand, when the rotation speed of the plate is 70 r/min, the pressure differential is 9 mm H2O, which is 1.5 times that of 0 rpm rotation speed. The spiral tube valveless piezoelectric pump can turn the element attitude into a form of pressure output, which is important for the multi-function integration of the valveless piezoelectric pump and for the development of civil gyroscope in the future. (C) 2013 Elsevier B.V. All rights reserved.