Engine integration based on multi-disciplinary optimisation technique

Abstract

The paper presents the work related to the engine integration of a Rear Fuselage Mounted Engine configuration in the frame of the DLR/Onera project MDOrmec ("Multi-Disciplinary Optimisation of Rear-fuselage Mounted Engine Configuration"). The developed multidisciplinary optimization process is based on a multi-level fidelity approach, where the aerodynamics is simulated using CFD methods while the weight and the handling qualities are assessed using preliminary design approach. Finally, the results of the optimisation are presented and discussed in detail.

Development of a Multidisciplinary Design Optimization Framework Applied on UAV Design by Considering Models for Mission, Surveillance, and Stealth Performance

“…The hypothetical longitudinal position of the CG where the aircraft stability is neutral is called the Neutral Point (NP) [13] Among other things, the SM defines the pitch stability of the aircraft and hence, it is clear that the design should be within a predefined range [11], [12]. Provided that there is no dynamic model in a MDO framework for predicting the flight characteristics, the SM can be used simply as a constraint like in the case-studies of Choi et al [16] and Haar et al [17]. Amadori et al [18] included the SM in the objective function as a penalty, whereas Lundström et al [15] approached the stability issue by including an internal loop which balances the aircraft for every optimization evaluation.…”

“…In this way, it was possible to get the curves of the lift and the induced drag coefficients as a function of the AoA and therefore, they were able to make performance calculations at various flight conditions. A similar approach but with CFD tools was followed by Hitzel et al [19] on a standardtail configuration UAV design and by Haar et al [17] on a generic aircraft with rear-mounted engines. The difference of [19] is that they isolated the horizontal stabilizer from the rest of the aircraft so that they could evaluate it at different AoA.…”

“…Range and endurance are often encountered in MDO studies as optimization objectives [15], [16], [17], [19], [29], [30] or constraints [18]. The reason for this is that the definitions of both the range and the endurance include aerodynamic and weight parameters but are also integrated for over a mission segment as seen in formulas (2.11) and (2.12).…”

“…The reason for this is that the definitions of both the range and the endurance include aerodynamic and weight parameters but are also integrated for over a mission segment as seen in formulas (2.11) and (2.12). Therefore, it is possible to have a single objective that expresses a design improvement which is related to both structural and aerodynamic performance but also considers the flight conditions [17], [30].…”

Development and application of multi-disciplinary optimization capabilities based on high-fidelity methods

“…The key elements are presented in Figure 29 and a more comprehensive description of the process chain is given in 50 . Only the key elements are now briefly introduced.…”