Energy saving potential of aerodynamic optimized propeller-driven configuration in dependence of aircraft size

Abstract Aerodynamic interactions between propellers and wings can be utilized to increase the energy efficiency of aircraft in cruise flight. Aircraft concepts dedicated to exploit the interactions are wingtip mounted propellers (WTP) and distributed propulsion (DP). The simulation results for three wings corresponding to different aircraft types differing in cruise Mach number and PAX are compared. Thereby, it is determined whether the previously examined findings with the wing of a 19 PAX Beechcraft 1900D type aircraft are only valid for this specific design or replicable. For this purpose, the wings of a Cessna 208 Caravan type aircraft as an example for a 9 PAX and an ATR 42 as a 50 PAX are now considered in addition. In the first part, CFD simulations for the three wings with different propeller-wing arrangements (WTP, partial DP, full DP) in cruise flight are evaluated with respect to the required power and compared with each other. In addition, the influence of the spanwise propeller position and the inclination angle is compared for the 19 and the 50 PAX wings and in the second part, the transferability of the wing-propeller simulations to the aircraft level as well as the energy and emission saving potential of propeller-driven configurations with partial DP are discussed. The second order finite volume flow solver TAU is used for the numerical simulations, employing Reynolds-Averaged Navier–Stokes equations. The influence of the propeller on the wing is modeled with a steady state Actuator Disc method. The study shows that the interactions are qualitatively and quantitatively similar for different aircraft sizes. With partial DP configurations, a saving in required power of approximately 4-5\% can be expected relative to conventional propeller driven aircraft purely by utilizing the aerodynamic interactions.