Numerical Investigation of High-Lift Propeller Positions for a Distributed Propulsion System

Abstract

The aerodynamic propeller–wing interactions of a distributed propulsion system in a high-lift scenario were investigated. A [Formula: see text] computational fluid dynamics parameter study with steady-state Reynolds-averaged Navier–Stokes simulations of a wing segment and an actuator disk was conducted to determine the sensitivities and correlations of design parameters at high angles of attack. The parameter study revealed a significant lift augmentation (about [Formula: see text] at [Formula: see text]) but a decrease in propulsive efficiency (about [Formula: see text] at [Formula: see text]). With increasing angle of attack, the lift augmentation effect decreased (down to about [Formula: see text] at [Formula: see text]), whereas the propulsive efficiency decreased further (to about [Formula: see text] at [Formula: see text]). The design parameter presenting the largest sensitivity toward system performance was the vertical propeller position. The distance between the propeller and the wing had a comparatively minor effect, as long as the vertical propeller position was adapted accordingly. Propulsive performance could be significantly improved by tilting the propeller downward toward the inflow (by about [Formula: see text] for [Formula: see text] as compared to a nontilted propeller). A spanwise clustering of propellers (tip-to-tip distance of [Formula: see text]) appears to be beneficial when considering a predetermined amount of distributed propellers.

System Performance of Wing and Propellers in a Periodic Distributed Propulsion Experiment

“…Main objective of this paper is to provide a measure of the system performance of a DP wing introduced by Firnhaber [1]. This is necessary in order to take the step from individual efficiency values for propeller and wing towards a combined evaluation of a periodic DP wing section.…”

“…A large set of variations, including propeller position, thrust level, flap angle and more was carried out. In the presented work we focus on the system efficiency defined by Firnhaber [1] to evaluate the performance of a DP-Wing. This parameter serves as a global figure of merit for a DP wing section with periodic boundary conditions.…”