The wing area behind the pylon-wing junction of conventional civil aircraft configurations with underwing-mounted turbofan engines is susceptible to local flow separation at high angles of attack, which potentially impacts the maximum lift performance of the aircraft. With further advances in turbofan engine technology, bypass-ratios will reach levels of larger than 15:1. As long as no drastic configuration changes are introduced, these engines will need to be coupled even closer to the wing which limits the extent of the inboard slat further, resulting in stall-inducing flow separation at high angles of attack. This dissertation fills in the research gap, by focusing on the application of an Active Flow Control system for separation control at the pylon-wing junction. In focus of the work is the application on an aircraft-scale model which covers the key drivers of a realistic aircraft application. A flow control concept on basis of an unsteady fluidic actuator has been implemented into the wind tunnel model design. The aerodynamic effect of this flow control actuator has been studied with the help of force and pressure measurements, as well as flow visualization. Results have shown a compelling effect of the actuation: the lift is increased across a wide range in angle of attack originating from a reduction of the local separation behind the pylon-wing junction. Further testing on a realistic configuration underlines the results of aircraft-scale testing. Reynolds and Mach number scaling play an important role on the investigated high-lift configuration. The aircraft-scale test is a necessity to avoid such influences on the flow control investigations. In conclusion, unsteady fluidic actuation has been proven to delay local separation behind the pylon-wing junction. The flow control system could satisfy the requirements with respect to the aerodynamic effect and the industry-relevant constraints. The presented results increase the comprehension of the underlying flow mechanisms and pave the way for further industry-relevant research and applications.
Aircraft-scale application of active separation control at the pylon-wing junction
Untersuchung von aktiver Strömungskontrolle im Flugzeugmaßstab im Bereich der Triebwerksaufhängung
2019
Sonstige
Elektronische Ressource
Englisch
DDC: | 629 |