Analysis and testing of a THUNDER™ piezoelectric actuator as a prime mover in a gas flow control valve

This paper presents an experimental analysis in which a THUNDER (TM) (Thin Unimorph DrivER) actuator was used to adjust the flow of air through a specified cross sectional area inside a Plexiglas housing. The THUNDER (TM) is a curved, bilayer actuator made up of a piezoelectric layer and a stainless steel layer. In this work the THUNDER (TM) is used as the prime mover in an air flow control valve. The valve is made up of a flow channel that allows air to pass over the top of the actuator. When voltage is applied to the actuator, the piezoceramic layer expands or contracts, changing the actuator's curvature, thus changing the orifice area in the valve resulting in a change in flow. Testing is done with single and dual flow loop arrangements. In the dual flow loop, one flow line contains the control valve while the other is a bypass line. The valve is used to balance flow between the lines. Both lines have adjustable outlet valves so that the valve can be tested under a wide range of flow conditions. Several lids for the control valve were manufactured and tested to reveal the possibility of increase modulation performance using alternative channel geometries. The test results showed that the THUNDER (TM) control valve could modulate the air flow by as much as 16% at 4.4 SCFM (125 LPM) in single loop flow and 30% at 2.3 SCFM (65 LPM) in dual loop flow for inlet pressures up to 25 PSI (172 kPa).