Preliminary overall aircraft design with hybrid laminar flow control

  • Vorentwurf von Flugzeugen mit hybrider laminarer Strömungskontrolle

Risse, Kristof; Stumpf, Eike (Thesis advisor); Schröder, Wolfgang (Thesis advisor)

Aachen : Shaker (2016, 2017)
Book, Dissertation / PhD Thesis

In: Berichte aus der Luft- und Raumfahrttechnik
Page(s)/Article-Nr.: XXX, 200 Seiten : Illustrationen, Diagramme

Dissertation, RWTH Aachen University, 2016


This thesis deals with preliminary overall aircraft design including hybrid laminar flow control (HLFC) on wings and tails. An integrated methodology and software framework is developed that closes the gap between conceptual aircraft design capabilities and the detailed design tasks of HLFC aerodynamic wing design and HLFC system sizing. The key new achievement of the proposed approach compared to the current state of the art is its capability to perform overall aircraft design studies, while simultaneously capturing the specific influences of different transition mechanisms and transonic drag on swept-tapered wings, as well as the integration of the suction system into the wing.The "Multidisciplinary Integrated Conceptual Aircraft Design and Optimization" (MICADO) framework constitutes the basis for this integrated approach. MICADO consists of a consistent and flexible software architecture, a requirement-driven overall design philosophy, and several loosely-coupled program modules. Most significant elements for HLFC aircraft design are a thermodynamic engine model including secondary power extraction, overall-aircraft drag and mass prediction, and detailed mission performance simulation.The incorporation of HLFC aerodynamics into overall aircraft design is solved by a quasi-three-dimensional wing design approach, and a database containing multi-point optimized HLFC airfoils at different design conditions. An Euler/boundary-layer and a transition prediction code (including cross-flow instabilities) are combined with appropriate sweep-taper transformations into an iterative and robust drag prediction method for transonic HLFC wings. Both pressure and suction distributions are taken into account for automated estimation of power requirements and component masses of the suction system. Applicability and validity of the proposed HLFC aircraft design approach are demonstrated for a long range passenger aircraft. Influences of mass snowball effect, component resizing, and conservative fuel planning for in-flight loss of laminarity are quantified in terms of block fuel and other key design parameters. The significant fuel saving potential of HLFC is confirmed, and further exploited by the integrated design and optimization of HLFC wing geometries for maximum overall aircraft benefit.