ANALYSIS AND TESTING OF A THUNDER™ PIEZOELECTRIC ACTUATOR AS A PRIME MOVER IN A GAS FLOW CONTROL VALVE

摘要

The target of this research was to conduct an experimental analysis in which a THUNDER™ (Thin Unimorph DrivER) actuator was used to adjust the flow of air through a specified cross sectional area inside a Plexiglas housing. The THUNDER™ actuator was developed over ten years ago as a high displacement piezoelectric actuator. It is a curved, bilayer actuator made up of a piezoelectric layer (PZT, lead zirconate titanate) and a stainless steel layer. In this study, the THUNDER™ is 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, causing the piezo ceramic layer to expand or contract, the curvature of the actuator changes, thus changing the orifice area in the valve and causing 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. Pressure transducers were placed along the experimental setup to observe various pressures conditions in the system. Two flow meters were used to measure either the single loop flow rate or the corresponding flow rate in each line of the dual flow loop. Several lids for the control valve were manufactured and tested to reveal that alternative channel geometries could lead to increased performance over a specific range. The test results showed that the THUNDER™ 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).