Flight physics and Propulsion

In the area of flight physics and flight propulsion systems, the interactions between airfoils and flight propulsion in extreme high-lift configurations will be researched, and improved aeroacoustic design methods will be developed to reduce flight propulsion noise. For this reason, the “Citizen-Friendly Airplane” research program is performing the layout, design, and production of a broad-based validation experiment at the DNW-NWB wind tunnel in Braunschweig. This wind tunnel experiment consists of a half wing with compressed air supply for active Coanda high-lift flaps, and a compact electric drive with a low-noise high-performance propeller and maximum 200 kW drive power. The planned arrangement of airfoil, propeller, and engine nacelle are shown in the following figure.

design of a wind tunnel experiment

Simulations are currently being performed to validate the aerodynamic and structural properties of the design and construction of the wind tunnel model. The use of compact, high-performance electric drives of this power class in wind tunnel models is an innovation in experimental technology. Over the 5 years of the “Citizen-Friendly Airplane” program, investigations are planned into the aerodynamic and acoustic properties of the arrangement shown, with the propeller in front of the airfoil, with active high-lift flaps and stationary expulsion of compressed air. This will provide for the first time an experimental database to validate the numerical simulations. A significant reduction in engine noise can only be achieved through a combination of lower velocities and therefore larger rotors (propellers), as well as covering, partial covering, and noise shielding by parts of the aircraft. For future design processes for the partially or fully sheated installed propulsor, the DLR and TU Braunschweig research partners are expanding the PIANO acoustic method of calculation for applications with rotating coordinates, and are developing new coupling techniques between the TAU and TRACE aerodynamic simulation procedures and the PIANO code. In addition, the PIANO code is being expanded so that, in the future, the effect of acoustic coatings to reduce tonal noise can be taken into account in noise analysis.

Another area of focus in the flight propulsion studies is looking at the acoustic and mechanical properties of the exhaust hot gas path, where metal structural foams are being developed and characterized as liner material. On the acoustic side, the propagation of combustion chamber noise through the turbine is being examined with numerical procedures and dedicated experiments to evaluate the potential for noise reduction using the new liner in the core engine.

Participating institutes:

Institute of Aerodynamics and Flow Technology, DLR
Institute of Aeroelasticity, DLR
Institute of Propulsion Technology, DLR
Institute of Flight Propulsion Systems and Jet Engines, TU Braunschweig
Institute of Fluid Mechanics, TU Braunschweig
Institute of Turbo-engines and Fluid Dynamics, LU Hannover
Institute of Materials, TU Braunschweig

  last changed 21.12.2011
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