Active Vortex Generator Deployed On Demand by Size Independent Actuation of Shape Memory Alloy Wires Integrated in Fiber Reinforced Polymers

摘要

Flow control functions are often required in areas where construction space as well as weight is premium. Furthermore, there is a huge range of control surface sizes, beginning with large-scale rudders like ailerons with some meters of length down to small-scale control surfaces like trimming tabs or vortex generators with some centimeters of size. An actuation principle covering all these applications needs to be highly scalable. However the current state of the art actuator-mechanical system solution is strongly limited. Active hybrid structures, combining the actuation of shape memory alloys (SMA) with fiber reinforced polymers (FRP) on the materials level, provide a scalable actuation principle with high lightweight potential. Also the compact design requires less construction space and makes the integration in the aircraft system simple. Being one of the first applications of active hybrid structures from SMA and FRP, the presented active vortex generators help to demonstrate the advantages of this new technology. Commonly used high performance airfoils show minimum drag and maximum lift, but tend to suddenly stall due to flow separation at low air speed. New active vortex generators, deployed only on demand at low speed, can help to overcome this contradiction without any drawback for cruise flight.