@inproceedings{MischkeKazulaHoeschler, author = {Mischke, Marcel and Kazula, Stefan and H{\"o}schler, Klaus}, title = {A Comparative Concept Study and Evaluation for New Broadband Noise Absorbing Acoustic Liner Concepts for Civil Aviation}, series = {Proceedings of Global Power and Propulsion Society, Technical Conference 2019, Zurich}, booktitle = {Proceedings of Global Power and Propulsion Society, Technical Conference 2019, Zurich}, pages = {1 -- 9}, abstract = {This paper presents an approach to product rating and evaluation of different product solutions for broadband attenuation acoustic liner concepts for aerospace application. In the process, corresponding requirements have been defined for the considered system and evaluation criteria have been derived. Three "Main Evaluation Categories" (Acoustics, System Safety and Integration, Structure and Material) have been introduced to not falsify the assessment results by subject-specific exclusion criteria. A ranked space method has been selected for weighting the evaluation criteria to ensure an objective and knowledge-based rating. The rating has been carried out by a weighted point rating. Concise operational requirements and previously not considered system functions have been identified and linked to the rating and evaluation process. Building on this, further steps for the optimisation and development of the acoustic liner concepts have been presented and explained.}, language = {en} } @misc{KazulaHoeschler, author = {Kazula, Stefan and H{\"o}schler, Klaus}, title = {A systems engineering approach to variable intakes for civil aviation}, series = {Proceedings of the Institution of Mechanical Engineers. Part G, Journal of Aerospace Engineering}, volume = {234(2020)}, journal = {Proceedings of the Institution of Mechanical Engineers. Part G, Journal of Aerospace Engineering}, number = {10}, issn = {2041-3025}, doi = {10.1177/0954410019836903}, pages = {1721 -- 1729}, abstract = {A systems engineering approach to develop variable nacelle intakes for aero engines in civil aviation is presented. The goal of this methodical approach is to find solutions to design problems that can be successfully utilised in aviation without further effort during the certification. By using variable intakes, aircraft and aero engine manufacturers can fulfil their customers' needs for safe, efficient and fast travelling. Therefore, a system shall be installed which is able to modify the nacelle intake contour between two extrema. On the one hand, a sharp thin contour, which produces low drag and allows to fly faster or more efficiently, is optimal during cruise condition. On the other hand, a round thick intake lip is necessary to avoid flow separations with the potential to cause dangerous events during take-off and climb conditions. The utilised systems engineering approach is introduced. The executed steps and methods used for creating and evaluating concept variants for variable intakes are displayed particularly. Those contain the determination and evaluation of requirements and functions as well as the generation and assessment of concepts. Finally, yet importantly, following tasks are presented.}, language = {en} } @misc{KazulaWoellnerGrasseltetal., author = {Kazula, Stefan and W{\"o}llner, Mark and Grasselt, David and H{\"o}schler, Klaus}, title = {Parametric Design Study on Aerodynamic Characteristics of Variable Pitot Inlets for Transonic and Supersonic Civil Aviation}, series = {MATEC Web of Conferences : Proceedings of the 9th EASN International Conference on Innovation in Aviation \& Space}, volume = {304}, journal = {MATEC Web of Conferences : Proceedings of the 9th EASN International Conference on Innovation in Aviation \& Space}, issn = {2261-236X}, doi = {10.1051/matecconf/201930402017}, pages = {8}, abstract = {This paper reveals the influence of selected geometric parameters on the aerodynamic performance of circular variable aero engine inlets in transonic and supersonic civil aviation. The trade-off in inlet design and aerodynamic evaluation parameters are presented. The approach to investigate the dependencies between the aerodynamic and geometric parameters at different flight conditions by means of a parametric design study is introduced. The dependencies of inlet drag and efficiency from geometric parameters at flight speeds of Mach 0.95 up to Mach 1.6 are identified. Although entailing additional weight, the inlet length represents the parameter with the highest potential for drag reduction by up to 50\% in the selected design space. Ideal geometries for variable pitot inlets are determined. After considering weight, their potential range benefit nearly disappears for subsonic applications, but remains above 20\% for supersonic flight at Mach 1.6.}, language = {en} } @misc{KazulaMischkeKoenigetal., author = {Kazula, Stefan and Mischke, Marcel and K{\"o}nig, Paul and H{\"o}schler, Klaus}, title = {Evaluation of Variable Pitot Inlet Concepts for Transonic and Supersonic Civil Aviation}, series = {MATEC Web of Conferences : Proceedings of the 9th EASN International Conference on Innovation in Aviation \& Space}, volume = {304}, journal = {MATEC Web of Conferences : Proceedings of the 9th EASN International Conference on Innovation in Aviation \& Space}, issn = {2261-236X}, doi = {10.1051/matecconf/201930402016}, pages = {8}, abstract = {This paper describes the selection of the ideal variable inlet concept group by utilising results of aerodynamic investigations, system safety analyses and integration studies. Aerodynamic and functional inlet requirements are explained and variable inlet concept groups are introduced. The concept evaluation by means of a weighted point rating is presented. The respective concept groups are analysed and evaluated regarding economic, functional and safety requirements. By means of this evaluation, the concept group that adjusts the inlet geometry by rigid segment repositioning is identified as most suitable concept group. The early selection of the most suitable concept group enables more detailed subsequent concept investigations, potentially enabling the technology of variable inlets for future commercial aircraft.}, language = {en} } @misc{KazulaWoellnerGrasseltetal., author = {Kazula, Stefan and W{\"o}llner, Mark and Grasselt, David and H{\"o}schler, Klaus}, title = {Parametric design and aerodynamic analysis of circular variable aero engine inlets for transonic and supersonic civil aviation}, series = {Proceedings of the 24th ISABE Conference : ISABE 2019-24018}, journal = {Proceedings of the 24th ISABE Conference : ISABE 2019-24018}, address = {Canberra}, pages = {39}, abstract = {This paper focusses on the challenge of determining the ideal inlet geometries within a concept study for variable pitot aero engine inlets in transonic and supersonic civil aviation. The trade-off in inlet design and the geometric parameters of inlets for different Mach numbers are introduced. The utilised process of the parametric design study and its implementation are presented. The dependencies of inlet drag and occurrence of flow separation from geometric parameters are examined. The ideal inlet geometries are identified to determine the potential aerodynamic benefit of using variable pitot inlets. The comparison of the identified geometries with the reference reveals a significant drag reduction at the investigated flight speeds of Mach 0.95, 1.3 and 1.6. While the drag reduction potentially leads to decreased fuel consumption and increased flight range, the application of variable inlet systems entails additional weight and complexity. By means of a simplified Breguet range equation, the benefit of using variable pitot inlets has been determined. For an additional weight of 500 kg per variable inlet, the range benefit nearly disappears for subsonic applications up to Mach 0.95, while a range benefit of over 20\% remains for supersonic applications at Mach 1.6.}, language = {en} } @misc{KoenigMischkePohletal., author = {K{\"o}nig, Paul and Mischke, Marcel and Pohl, Michael and Kazula, Stefan and H{\"o}schler, Klaus}, title = {Concept Development and Evaluation for a Broadband Noise Absorbing Acoustic Liner Concept for Aviation}, series = {24th International Society For Air Breathing Engines (ISABE-2019-24261), 22.-27. September 2019}, journal = {24th International Society For Air Breathing Engines (ISABE-2019-24261), 22.-27. September 2019}, abstract = {This paper presents design adaptations during the further development of innovative broadband acoustic liner concepts (Foil Helmholtz Resonator Liner; FHR-Liners) which utilise flexible foils within a honeycomb structure to attenuate engine and aircraft noise. The requirements for acoustic liners in aviation are described and utilised to derive evaluation criteria. Modifications of the FHR-Liner concept are introduced. A suitable concept evaluation method based on VDI 2225 is applied to evaluate the modified liner concepts concerning the main evaluation criteria.}, language = {en} } @misc{KazulaWoellnerGrasseltetal., author = {Kazula, Stefan and W{\"o}llner, Mark and Grasselt, David and H{\"o}schler, Klaus}, title = {Ideal Geometries and Potential Benefit of Variable Pitot Inlets for Subsonic and Supersonic Business Aviation}, series = {8TH EUROPEAN CONFERENCE FOR AERONAUTICS AND SPACE SCIENCES (EUCASS)}, journal = {8TH EUROPEAN CONFERENCE FOR AERONAUTICS AND SPACE SCIENCES (EUCASS)}, doi = {10.13009/EUCASS2019-314}, abstract = {The challenge of determining ideal inlet geometries for variable pitot aero engine inlets in transonic and supersonic civil aviation is presented. The trade-off in inlet design and the geometric inlet parameters are introduced. By means of a parametric design study, feasible inlet geometries for variable inlets are identified and the potential aerodynamic benefit of using variable pitot inlets for flight speeds from Mach 0.95, 1.3 up to 1.6 is examined. After considering the additional weight of variable inlets, for instance due to required actuators, a remaining range benefit of over 20\% at a flight speed of Mach 1.6 is determined.}, language = {en} } @misc{MischkeKazulaHoeschler, author = {Mischke, Marcel and Kazula, Stefan and H{\"o}schler, Klaus}, title = {Preliminary Safety Assessment on System Design Level for Broadband Acoustic Liner Concepts for Aviation}, series = {Proceedings of the 9th EASN International Conference on Innovation in Aviation \& Space}, journal = {Proceedings of the 9th EASN International Conference on Innovation in Aviation \& Space}, address = {Athen}, doi = {10.1051/matecconf/201930404010}, pages = {8}, abstract = {Selected methods of the aviation safety assessment process according to ARP 4761 are introduced and conducted within the scope of a concept study for future broadband acoustic liners. While having similar primary functions and basic design, the acoustic liner concepts diverge concerning subfunctions and potential malfunctions. With the ARP 4761 safety assessment methods, significant differences in sub functions and possible malfunctions of the concepts can be identified. The results of the safety assessment are discussed, and the concepts are evaluated in terms of feasibility and safety.}, language = {en} }