Piezohydraulic Actuator Development for Microjet Flow Control

This paper describes the development of a piezohydraulic actuator for broadband microjet flow control applications. The actuator utilizes a lead zirconate titanate (PZT) stack actuator and a hydraulic amplification design to achieve relatively large displacements in a compact actuator to control flow through a microjet orifice. Displacement amplification of 81 times the stack actuator displacement was achieved using a new dual-diaphragm design. The nonlinear and hysteretic field-coupled material behavior, structural dynamics, and fluid dynamics of the actuator are modeled using a system dynamic model and compared with experimental results. The nonlinear and hysteretic piezohydraulic actuator characteristics are shown to be strongly dependent on the nonlinear deformation of the rubber diaphragm and minor loop hysteresis of the PZT stack actuator. The modeling technique provides a design tool for broadband performance predictions and system optimization to facilitate implementation of the actuator in a flow environment.