Conceptual design studies of unconventional configurations Michael Iwanizki, Sebastian Wöhler, Benjamin Fröhler, Thomas Zill, Michaël Méheut, Sébastien Defoort, Marco Carini, Julie Gauvrit-Ledogar, Romain Liaboeuf, Arnault Tremolet, et al. To cite this version: Michael Iwanizki, Sebastian Wöhler, Benjamin Fröhler, Thomas Zill, Michaël Méheut, et al.. Concep- tual design studies of unconventional configurations. 3AF Aerospace Europe Conference 2020, Feb 2020, BORDEAUX, France. hal-02907205 HAL Id: hal-02907205 https://hal.archives-ouvertes.fr/hal-02907205 Submitted on 27 Jul 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. CONCEPTUAL DESIGN STUDIES OF UNCONVENTIONAL CONFIGURATIONS M. Iwanizki (1) , S. Wöhler (2) , B. Fröhler (2), T. Zill (2), M. Méheut (3), S. Defoort (4), M. Carini (3), J. Gauvrit-Ledogar (5), R. Liaboeuf (4), A. Tremolet (5), B. Paluch (6), S. Kanellopoulos (3) (1)DLR, Lilienthalplatz 7, 38108 Braunschweig (Germany), Email: [email protected] (2)DLR, Hein-Sass-Weg 22, 21129 Hamburg (Germany), Email: [email protected], [email protected], [email protected] (3)ONERA - The French Aerospace Lab - 92190 Meudon (France), Email:[email protected], [email protected], [email protected] (4)ONERA - The French Aerospace Lab - Toulouse (France), Email:[email protected], [email protected] (5) ONERA - The French Aerospace Lab - Palaiseau (France), Email:[email protected], [email protected] (6)ONERA - The French Aerospace Lab - Lille (France), Email:[email protected] KEYWORDS: Blended Wing Body, Forward Fig. 1. This paper is limited to the conceptual Swept Wing, Strut Braced Wing, Tailless design studies that partially include the results of Aircraft, Joined Wing, 3-Surfaces, Large high fidelity analyses and simulations for some of Fuselage, Conceptual Design, Overall Aircraft the configurations. Design, Performance Analysis, MYSTIC, RCE, CPACS, MICADO, Clean Sky 2 ABSTRACT The potential of unconventional configurations to reduce the fuel consumption of future aircraft is investigated in the European Clean Sky 2 (ITD Airframe) ONERA-DLR project “NACOR” (New fidelity Level of Aircraft Concepts Research - Call for Core Partners Wave 1). Two design missions are Number of configurations considered: a short/medium range mission (SMR) Figure 1: Overview of the evaluation process. based on the requirements of an Airbus A320, and a business jet (BJ) mission. In this paper, an 2. OVERVIEW OF CONFIGURATIONS overview of the activities considering the In this section, a brief overview of the novel conceptual aircraft design phase including initial configurations discussed in this paper is given. high fidelity studies is provided. They have been selected based on rough quantitative estimates of the lift-to-drag ratio (L/D) 1. INTRODUCTION and the operating empty mass (OEM) as a result Following the challenging targets defined in the of an earlier project phase. The assessment work Flightpath 2050 [1], DLR and ONERA investigate was shared between ONERA and DLR. several unconventional aircraft configurations that could reduce the environmental impact of the air transportation in future. A stepwise analysis process is applied in order to cover a wide design space on the one hand, and to allow for deep analyses of the most promising concepts on the other. TA JW At the beginning of the process, a large number of configurations is evaluated with simple methods as expert based rankings. The most promising concepts are selected for more detailed analyses in the next step. In each following step methods with higher fidelity are applied and a SBFSW BWB downselection of concepts is performed. A generic overview of this process is provided in Figure 2: Novel configurations for SMR mission. For the BWB, mass estimation methods were derived and implemented based on previous studies within the European Vela project [5]. 3.2. Aircraft design environment MICADO FSW 3S LF The aircraft design environment MICADO Figure 3: Novel configurations for BJ mission. (Multidisciplinary Integrated Conceptual Aircraft For the SMR mission, four concepts are Design and Optimization, which is a licensed investigated: the “Tailless Aircraft” (TA), the product of the ILR of RWTH Aachen University) “Joined Wing” (JW), the “Strut Braced Forward [6] is used for the design and the analysis of the Swept Wing” (SBFWS), and the “Blended Wing SBFSW and FSW-BJ configurations at DLR. Body” (BWB), that is referred to also as the MICADO consists of loosely coupled modules that “Alternate Blended Wing Body” (aBWB), if it is represent the major disciplines in the conceptual equipped with a canard. These are shown in aircraft design. It utilizes a combination of semi- Fig. 2. In Fig. 3, the concepts for the business jet empirical and low level physics based methods, mission are depicted: the “Forward Swept Wing” as e.g. the vortex lattice code LIFTING_LINE of (FSW), the “Three Surface Aircraft” (3-S), and the DLR [7]. MICADO also enables to perform “Large Fuselage” (LF). automated parameter studies and optimization. The design methodology of MICADO, as provided 3. DESCRIPTION OF TOOLS by Risse in [8], is shown in Fig. 4. In this section, the tools applied in the scope of this work are described. Both, ONERA and DLR utilize their own tools. But also for different configurations different tools were applied. In order to ensure the comparability of results, the tools were calibrated and validated utilizing identical baseline configurations. 3.1. Aircraft design workflow in RCE The overall aircraft design workflow embedded in the Remote Component Environment RCE [2] is utilized for the analysis of the TA and the BWB configurations at DLR. The design workflow covers the range of tools from Level 0 (L0), considering (semi-) empirical methods, over Level 1 (L1), taking into account low level physics based methods, to Level 2 (L2), using high fidelity methods. It also contains a Design of Experiments (DOE) capability and the post processing. The modules implemented are easily exchangeable to adapt the workflow for specific configurations or higher level of fidelity in specific domains, if different methods are needed. Figure 4: MICADO workflow [8] To ensure such flexibility the standard data exchange format Common Parametric Aircraft For the assessment of unconventional aircraft, Configuration Scheme (CPACS) [3,4] is utilized to additional models for the calculation of masses of assure a consistent aircraft model throughout all unconventional wing configurations from [9] have communications between the involved modules. been introduced. The outcomes from [10] and [11] Hence the specific design environment enables a related to the design and performance of swept network based design approach also linking tools wings with natural laminar flow (NLF) have been of the various domains and institutes within the considered. DLR via the xml-based input and output files. For the initial evaluation of the novel TA and BWB 3.3. MYSTIC configurations solely the low-level part of the On ONERA side, to assess the performance of workflow (L0-L1) has been adapted and applied. the different concepts for both missions, the MYSTIC Overall Aircraft Design (OAD) process geometrical parameterization is shared among all has been used (Fig. 5). This process was used for the modules and enables to generate an all configurations (JW, 3S, LF) except the BWB. OpenVSP CAD model [14] for visualization and disciplinary simulation purposes. This tool incorporates physical modules for the classical disciplines of Overall Aircraft Design: 3.4. A dedicated process for BWB - CICAV Propulsion, Aerodynamics, Mass breakdown and As a complement to MYSTIC, the evaluation of balance, Handling qualities, Trajectory and the BWB configuration on the ONERA side Performance [12]. benefitted from a parallel internal effort dedicated to this kind of configuration. The aim of the CICAV project is to define a fully integrated process to parameterize, evaluate and size a BWB concept, using relevant disciplinary modules. The process [15] uses similar modules as those described in the previous section, but incorporates specific features relevant for a BWB configuration: - A cabin sizing module enables to fully describe the seats arrangement into compartments, depending on the sweep angle and payload Figure 5: Inputs and outputs of the MYSTIC tool. description. An illustration is given on Fig. 7; - A dedicated L1 mass module based on mixed Three sizing loops are implemented, allowing the empirical and FEM formulations adapted to the design of an aircraft upon its top level aircraft structural concept of the BWB provides a good requirements (TLARs) with iterations on the estimate of OEM and CG position; disciplinary modules (Fig. 6): - A specific L0 aerodynamic module, fine-tuned • Loop 1: design of HTP and VTP surfaces with CFD results, enables a quick evaluation of upon trim and stability HQ criterions at take- the aerodynamic performances on the whole off and in