Abstract
Distributed propulsion configurations are a promising concept for future aircraft systems. The main objective of the presented experiment is to investigate propeller-wing interactions in detail. An understanding of the interactions is deducted from the experiment. Furthermore, a data basis for numerical studies is created. In the work presented, the interaction between adjacent propellers as well as the two-way interaction of wing and propellers is studied. The designed wind tunnel model features a two element wing c = 0.8 m with three co-rotating propulsion units with a diameter of DP = 0.6 m or DP = 0.4 m. They are mounted on a separate carrier, which is installed in the test section of the Propulsion Test Facility, TU Braunschweig. The outboard sections generate periodic boundary conditions, whereas the centre wing and propeller are subject of analysis. Both the centre wing and the centre propeller are instrumented for force and moment measurements. The flap of the wing is freely adjustable. The detached setup of wing and propeller allows a variable adjustment of the relative propeller position to the wing. This feature allows the propeller to be moved in all directions. In this work the position varies from horizontally −0.489 < x/c < −0.114, vertically −0.2 < z/c < 0 and spanwise 0.075 < y/c < 0.375 in small increments. The effect of the wings upstream flow field on the propeller is compared and analyzed for different positions. In addition to the relative position, three different propeller blades are investigated, which differ in size and design. While two blades were designed for minimum induced losses, a third set of blades was designed for homogeneous induced velocity. A comparison for the isolated propeller and the DP configuration is shown. The thrust level is varied by blade pitching.
