Active flow control in aircraft
The airline industry relies heavily on wind tunnel testing of models and components to avoid or minimise the time, expense and risk of in-flight testing. Synthetic jets created when a membrane or diaphragm moves up and down or sucks and blows air are integral to the study of aircraft aerodynamics. Conventionally, synthetic jet actuators are based on a piezoelectric patch applied to a metallic disc, the latter of which is commercially available and used for low-quality speakers. Reliability is an issue and there is no health monitoring available. Responding to the need for an effective, efficient and reliable synthetic jet actuator as a plug - and - play unit for wind tunnel testing, scientists initiated the EU-funded project VELOCIRAPTOR. They sought to provide an advanced and superior alternative to current membranes. In a little over a year, VELOCIRAPTOR delivered an array of 30 synthetic jet actuators in a single, linear system. In addition to higher power density, integrated health monitoring will increase reliability and service lifetime. Each actuator employs a commercial, off – the – shelf piezoelectric diaphragm attached to a brass plate. The array module is produced with rapid prototyping with manufacturing supporting more complex geometries with fewer parts per module and a 75% reduction in lead time. Power density is increased by maintaining peak jet exit velocity in 50% smaller usable depth. Sensors integrated in each synthetic jet actuator enable real-time health monitoring. Such monitoring is expected to be a pillar of future certification requirements for in-flight active flow control systems making the technology primed for additional applications. With relatively simple modifications to engineering design, VELOCIRAPTOR delivered an advanced active flow control system (synthetic jet actuator array) with integrated health monitoring. It was produced for wind tunnel testing needs but is an obvious candidate for eventual use as in-flight active flow control. The latter is an important component of aerospace research to enhance aerodynamic performance while reducing drag, fuel consumption and emissions.
Keywords
Wind tunnel testing, active flow control, health monitoring, synthetic jet actuators, plug - and – play, piezoelectric diaphragm, brass plate, sensors
