Aerodynamic Investigation of Propulsion Integration for a Low Noise Hybrid Wing-Body with Podded UHBR Turbo Fan Engines

Abstract

Within the framework of the SIAM project, the DLR is investigating a novel low noise aircraft concepts for short- and medium range. With regards to noise impact the hybrid wing body with over the body mounted engines appears promising due to shielding effects. The installation of the engines for this type of configuration can be either realized with podded engines or buried engines. Both installation concepts have their advantages and disadvantages. While the buried engines are thought to be the more efficient option in particular when exploiting the benefits of boundary layer ingestion, it may pose a challenge to the engine design. Moreover, it clearly removes available space from the compartment below the engine, in this case the center body. The podded installation is thought to be the more conservative approach, as it poses less challenges to the airframe and engine design while promising less aero-propulsive efficiency. The presented work investigates the aerodynamic challenges of podded ultra high-bypass engines installed on a low noise hybrid wing body configuration. First, sensitivity studies regarding the impact of the freestream Mach number, engine position, and the engine incidence angle on the interference drag are discussed. Then, shape modifications of the nacelle and the center body based on 2D RANS optimizations are presented. The results indicate that in order to reduce the initial massive interference drag the overall aircraft design either has to allow for a modified engine position or for reshaping of the center body's upper surface.