TY - CHAP A1 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - Case studies in initial sizing for hybrid-electric general aviation aircraft T2 - 2018 AIAA/IEEE Electric Aircraft Technologies Symposium, Cincinnati, Ohio Y1 - 2018 U6 - https://doi.org/10.2514/6.2018-5005 ER - TY - CHAP A1 - Finger, Felix T1 - Comparative Performance and Benefit Assessment of VTOL and CTOL UAVs T2 - Deutscher Luft- und Raumfahrtkongress (DLRK) 2016, 13.-15.9.2016 Y1 - 2016 ER - TY - CHAP A1 - Peeken, Heinz A1 - Troeder, Christoph A1 - Schmidt, J. A1 - Rosenkranz, Josef T1 - Principles of machine noise reduction T2 - Inter-noise 85 : proceedings ; 1985 international conference on noise control engineering ; Munich, Sept. 18 - 20, 1985. - (Schriftenreihe der Bundesanstalt für Arbeitsschutz : Tagungsbericht ; 39) Y1 - 1985 SN - 3-88314-417-7 SP - 23 EP - 36 PB - Bundesanstalt für Arbeitsschutz [u.a.] CY - Dortmund [u.a.] ER - TY - CHAP A1 - Funke, Harald A1 - Haj Ayed, A. A1 - Kusterer, K. A1 - Keinz, Jan A1 - Kazari, M. A1 - Kitajima, J. A1 - Horikawa, A. A1 - Okada, K. T1 - Numerical Study on Increased Energy Density for the DLN Micromix Hydrogen Combustion Principle T2 - Combustion, Fuels and Emissions (ASME Turbo Expo 2014: Turbine Technical Conference and Exposition : Düsseldorf, Germany, June 16–20, 2014 ; Vol. 4A) Y1 - 2014 SN - 978-0-7918-4568-4 N1 - Paper No. GT2014-25848 SP - V04AT04A057 PB - ASME CY - New York, N.Y. ER - TY - CHAP A1 - Mertens, Josef ED - Nitsche, Wolfgang T1 - Some important results of the technology programme RaWid T2 - New Results in Numerical and Experimental Fluid Mechanics : Contributions to the 11th AG STAB/DGLR Symposium Berlin, Germany 1998. - Vol. 2. - (Notes on Numerical Fluid Mechanics ; 72) Y1 - 1999 SN - 978-3-663-10903-7 (Print) SN - 978-3-663-10901-3 (Elektronisch) U6 - https://doi.org/10.1007/978-3-663-10901-3_41 SP - 315 EP - 322 PB - Springer Fachmedien CY - Wiesbaden ER - TY - CHAP A1 - Wahle, Michael T1 - Calculation of the response of heat exchanger tubes with regard to nonlinear and prestressing effects T2 - Vibration in nuclear plant : proceedings of the 3rd International Conference on Vibration in Nuclear Plant held on 11 - 14 May 1982, Keswick ; vol. 1 Y1 - 1983 SN - 0-7277-0192-4 (Druckausg.) SN - 978-0-7277-5270-3 (E-Book) N1 - International Conference on Vibration in Nuclear Plant <3, 1982, Keswick> N1 - Paper 1.10 (Log No. 71) SP - 162 EP - 183 PB - British Nuclear Energy Society CY - London ER - TY - CHAP A1 - Carzana, Livio A1 - Dachwald, Bernd A1 - Noomen, Ron T1 - Model and trajectory optimization for an ideal laser-enhanced solar sail T2 - 68th International Astronautical Congress N2 - A laser-enhanced solar sail is a solar sail that is not solely propelled by solar radiation but additionally by a laser beam that illuminates the sail. This way, the propulsive acceleration of the sail results from the combined action of the solar and the laser radiation pressure onto the sail. The potential source of the laser beam is a laser satellite that coverts solar power (in the inner solar system) or nuclear power (in the outer solar system) into laser power. Such a laser satellite (or many of them) can orbit anywhere in the solar system and its optimal orbit (or their optimal orbits) for a given mission is a subject for future research. This contribution provides the model for an ideal laser-enhanced solar sail and investigates how a laser can enhance the thrusting capability of such a sail. The term ”ideal” means that the solar sail is assumed to be perfectly reflecting and that the laser beam is assumed to have a constant areal power density over the whole sail area. Since a laser beam has a limited divergence, it can provide radiation pressure at much larger solar distances and increase the radiation pressure force into the desired direction. Therefore, laser-enhanced solar sails may make missions feasible, that would otherwise have prohibitively long flight times, e.g. rendezvous missions in the outer solar system. This contribution will also analyze exemplary mission scenarios and present optimial trajectories without laying too much emphasis on the design and operations of the laser satellites. If the mission studies conclude that laser-enhanced solar sails would have advantages with respect to ”traditional” solar sails, a detailed study of the laser satellites and the whole system architecture would be the second next step Y1 - 2017 N1 - 68th International Astronautical Congress: Unlocking Imagination, Fostering Innovation and Strengthening Security, IAC 2017, 2017-09-25 → 2017-09-29, Adelaide, Australia ER - TY - CHAP A1 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - The Impact of Electric Propulsion on the Performance of VTOL UAVs T2 - Deutscher Luft- und Raumfahrtkongress 2017, DLRK , München Y1 - 2017 ER - TY - CHAP A1 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - A Review of Configuration Design for Distributed Propulsion Transitioning VTOL Aircraft T2 - Asia-Pacific International Symposium on Aerospace Technology 2017, APISAT 2017, Seoul, Korea Y1 - 2017 ER - TY - CHAP A1 - Wahle, Michael T1 - Determination of flow induced nonlinear vibrations of prestressed heat exchanger tubes T2 - Advanced Course in Heat Exchangers : Theory and Practice ; ICHMT Symposium ; Dubrovnik, Croatia 1981. - (ICHMT digital library online ; 19) Y1 - 1983 SP - 339 EP - 353 PB - Begell House CY - Redding, Connecticut ER - TY - CHAP A1 - Nowack, N. A1 - Röth, Thilo A1 - Bührig-Polaczek, Andreas A1 - Klaus, G. ED - Hirsch, Jürgen T1 - Advanced Sheet Metal Components Reinforced by Light Metal Cast Structures T2 - Aluminium alloys : their physical and mechanical properties ; [proceedings of the 11th International Conference on Aluminium Alloys, 22 - 26 Sept. 2008, Aachen, Germany ; ICAA 11] Y1 - 2008 SN - 978-3-527-32367-8 IS - 2 SP - 2374 EP - 2381 ER - TY - CHAP A1 - Lettini, Antonio A1 - Havermann, Marc A1 - Guidetti, Marco A1 - Fornaciari, Andrea T1 - Improved functionalities and energy saving potential on mobile machines combining electronics with flow sharing valve and variable displacement pump T2 - 7th International Fluid Power Conference - Vol. 3 - Aachen Efficiency through Fluid Power Workshop Proceedings Y1 - 2010 SN - 978-3-940565-92-1 N1 - IFK, 7, Internationales Fluidtechnisches Kolloquium, 7., Aachen, DE, 2010-03-22 - 2010-03-24 SP - 103 EP - 114 PB - Apprimus Verlag CY - Aachen ER - TY - CHAP A1 - Recker, Elmar A1 - Bosschaerts, Walter A1 - Wagemakers, Rolf A1 - Hendrick, Patrick A1 - Funke, Harald A1 - Börner, Sebastian T1 - Experimental study of a round jet in cross-flow at low momentum ratio N2 - With the final objective of optimizing the "Micromix" hydrogen combustion principle, a round jet in a laminar cross-flow prior to its combustion is investigated experimentally using Stereoscopic Particle Image Velocimetry. Measurements are performed at a jet to cross-stream momentum ratio of 1 and a Reynolds number, based on the jet diameter and jet velocity, of 1600. The suitability to combine side, top and end views is analyzed statistically. The statistical theory of testing hypotheses, pertaining to the joint distribution of the averaged velocity along intersecting observation planes, is employed. Overall, the averaged velocity fields of the varying observation planes feature homogeneity at a 0.05 significance level. Minor discrepancies are related to the given experimental conditions. By use of image maps, averaged and instantaneous velocity fields, an attempt is made to elucidate the flow physics and a kinematically consistent vortex model is proposed. In the time-averaged flow field, the principal vortical systems were identified and the associated mixing visualized. The jet trajectory and physical dimensions scale with the momentum ratio times the jet diameter. The jet/cross-flow mixture converging upon the span-wise centre-line, the lifting action of the Counter Rotating Vortex Pair and the reversed flow region contribute to the high entrainment and mixedness. It is shown that the jet width is larger on the downstream side as compared to the upstream side of the centre-streamline. The deepest penetration of the particles on the outer boundary occurs in the centre-plane. Meanwhile, with increasing off-centre position, the boundaries all lay further from the centre-line position than does the boundary in the centre-plane, corresponding to a kidney-like shape of the flow cross-section. The generation of the Counter Rotating Vortex Pair and the instability mechanism is documented by instantaneous image maps and vector fields. The necessary circulation for the Counter Rotating Vortex Pair originates from a combined effect of steady in-hole, hanging and wake vortices. The strong cross-flow and jet interaction induces a three-dimensional waving, the stream-wise Counter Rotating Vortex Pair pair, leading to the formation of Ring Like Vortices. A secondary Counter Rotating Vortex Pair forms on top of the primary Counter Rotating Vortex Pair, resulting in mixing by "puffs". Overall, Stereoscopic Particle Image Velocimetry proofed capable of elucidating the Jet in Cross-Flow complex flow field. The gained insight in the mixing process will definitely contribute to the "Micromix" hydrogen combustion optimization. Y1 - 2010 N1 - 15th International Symposium on Applications of Laser Techniques to Fluid Mechanics Lisbon, Portugal, 05-08 July, 2010 ER - TY - CHAP A1 - Funke, Harald A1 - Robinson, A. E. A1 - Hendrick, P. A1 - Wagemakers, R. T1 - Design and Testing of a Micromix Combustor With Recuperative Wall Cooling for a Hydrogen Fuelled µ-Scale Gas Turbine T2 - Conference Proceedings ASME Turbo Expo 2010: Power for Land, Sea, and Air. Volume 5: Industrial and Cogeneration; Microturbines and Small Turbomachinery; Oil and Gas Applications; Wind Turbine Technology N2 - For more than a decade up to now there is an ongoing interest in small gas turbines downsized to micro-scale. With their high energy density they offer a great potential as a substitute for today’s unwieldy accumulators, found in a variety of applications like laptops, small tools etc. But micro-scale gas turbines could not only be used for generating electricity, they could also produce thrust for powering small unmanned aerial vehicles (UAVs) or similar devices. Beneath all the great design challenges with the rotating parts of the turbomachinery at this small scale, another crucial item is in fact the combustion chamber needed for a safe and reliable operation. With the so called regular micromix burning principle for hydrogen successfully downscaled in an initial combustion chamber prototype of 10 kW energy output, this paper describes a new design attempt aimed at the integration possibilities in a μ-scale gas turbine. For manufacturing the combustion chamber completely out of stainless steel components, a recuperative wall cooling was introduced to keep the temperatures in an acceptable range. Also a new way of an integrated ignition was developed. The detailed description of the prototype’s design is followed by an in depth report about the test results. The experimental investigations comprise a set of mass flow variations, coupled with a variation of the equivalence ratio for each mass flow at different inlet temperatures and pressures. With the data obtained by an exhaust gas analysis, a full characterisation concerning combustion efficiency and stability of the prototype chamber is possible. Furthermore the data show a full compliance with the expected operating requirements of the designated μ-scale gas turbine. Y1 - 2010 SN - 978-0-7918-4400-7 U6 - https://doi.org/10.1115/GT2010-23453 N1 - ASME Turbo Expo 2010: Power for Land, Sea, and Air, June 14–18, 2010, Glasgow, UK SP - 587 EP - 596 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Funke, Harald A1 - Börner, Sebastian A1 - Robinson, A. A1 - Hendrick, P. A1 - Recker, E. T1 - Low NOx H2 combustion for industrial gas turbines of various power ranges Y1 - 2010 N1 - 5th International Gas Turbine Conference ETN-IGTC, ETN-2010-42, Brussels, Belgium, October 2010 ER - TY - CHAP A1 - Börner, Sebastian A1 - Funke, Harald A1 - Hendrick, P. A1 - Recker, E. T1 - Control system modifications for a hydrogen fuelled gas-turbine T2 - Proceedings of ISROMAC 13 Y1 - 2010 SN - 978-1-617-38848-4 N1 - 13th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery 2010 (ISROMAC-13), Honolulu, Hawaii, USA, April 4-7, 2010 SP - 665 EP - 670 PB - Curran CY - Red Hook, NY ER - TY - CHAP A1 - Mulsow, Niklas A. A1 - Hülsen, Benjamin A1 - Gützlaff, Joel A1 - Spies, Leon A1 - Bresser, Andreas A1 - Dabrowski, Adam A1 - Czupalla, Markus A1 - Kirchner, Frank T1 - Concept and design of an autonomous micro rover for long term lunar exploration T2 - Proceedings of the 74th International Astronautical Congress N2 - Research on robotic lunar exploration has seen a broad revival, especially since the Google Lunar X-Prize increasingly brought private endeavors into play. This development is supported by national agencies with the aim of enabling long-term lunar infrastructure for in-situ operations and the establishment of a moon village. One challenge for effective exploration missions is developing a compact and lightweight robotic rover to reduce launch costs and open the possibility for secondary payload options. Existing micro rovers for exploration missions are clearly limited by their design for one day of sunlight and their low level of autonomy. For expanding the potential mission applications and range of use, an extension of lifetime could be reached by surviving the lunar night and providing a higher level of autonomy. To address this objective, the paper presents a system design concept for a lightweight micro rover with long-term mission duration capabilities, derived from a multi-day lunar mission scenario at equatorial regions. Technical solution approaches are described, analyzed, and evaluated, with emphasis put on the harmonization of hardware selection due to a strictly limited budget in dimensions and power. Y1 - 2023 N1 - 74. International Astronautical Congress (IAC-2023), October 2-6 2023, Baku, Azerbaijan PB - dfki CY - Saarbrücken ER - TY - CHAP A1 - Mayntz, Joscha A1 - Keimer, Jona A1 - Dahmann, Peter A1 - Hille, Sebastian A1 - Stumpf, Eike A1 - Fisher, Alex A1 - Dorrington, Graham T1 - Electrical Drive and Regeneration in General Aviation Flight with Propellers T2 - Deutscher Luft- und Raumfahrtkongress 2020 N2 - Electric flight has the potential for a more sustainable and energy-saving way of aviation compared to fossil fuel aviation. The electric motor can be used as a generator inflight to regenerate energy during descent. Three different approaches to regenerating with electric propeller powertrains are proposed in this paper. The powertrain is to be set up in a wind tunnel to determine the propeller efficiency in both working modes as well as the noise emissions. Furthermore, the planned flight tests are discussed. In preparation for these tests, a yaw stability analysis is performed with the result that the aeroplane is controllable during flight and in the most critical failure case. The paper shows the potential for inflight regeneration and addresses the research gaps in the dual role of electric powertrains for propulsion and regeneration of general aviation aircraft. KW - Propeller Aerodynamics KW - Flight Tests KW - Flight Mechanics KW - Electrical Flight KW - Inflight Regeneration, Recuperation Y1 - 2022 U6 - https://doi.org/10.25967/530100 N1 - Deutscher Luft- und Raumfahrtkongress 2020, 1. - 3. September 2020, Online PB - DGLR CY - Bonn ER - TY - CHAP A1 - Huth, Thomas A1 - Elsen, Olaf A1 - Hartwig, Christoph A1 - Esch, Thomas T1 - Innovative modular valve trains for 2015 - logistic benefits by EMVT T2 - IFAC Proceedings Volumes, Volume 39, Issue 3 N2 - In this paper the way to a 5-day-car with respect to a modular valve train systems for spark ignited combustion engines is shown. The necessary product diversity is shift from mechanical or physical components to software components. Therefore, significant improvements of logistic indicators are expected and shown. The working principle of a camless cylinder head with respect to an electromagnetical valve train (EMVT) is explained and it is demonstrated that shifting physical diversity to software is feasible. The future design of combustion engine systems including customisation can be supported by a set of assistance tools which is shown exemplary. Y1 - 2006 U6 - https://doi.org/10.3182/20060517-3-FR-2903.00172 N1 - Part of special issue "12th IFAC Symposium on Information Control Problems in Manufacturing" SP - 315 EP - 320 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Kohlberger, David-Sharif A1 - Wild, Dominik A1 - Kasper, Stefan A1 - Czupalla, Markus T1 - Modeling and analyses of a thermal passively stabilized LEO/GEO star tracker with embedded phase change material applying the Infused Thermal Solutions (ITS) method T2 - ICES202: Satellite, Payload, and Instrument Thermal Control N2 - Phase change materials offer a way of storing excess heat and releasing it when it is needed. They can be utilized as a method to control thermal behavior without the need for additional energy. This work focuses on exploring the potential of using phase change materials to passively control the thermal behavior of a star tracker by infusing it with a fitting phase change material. Based on the numerical model of the star trackers thermal behavior using ESATAN-TMS without implemented phase change material, a fitting phase change material for selected orbits is chosen and implemented in the thermal model. The altered thermal behavior of the numerical model after the implementation is analyzed for different amounts of the chosen phase change materials using an ESATAN-based subroutine developed by the FH Aachen. The PCM-modelling-subroutine is explained in the paper ICES-2021-110. The results show that an increasing amount of phase change material increasingly damps temperature oscillations. Using an integral part structure some of the mass increase can be compensated. KW - passive thermal control KW - PCM KW - star tracker KW - Infused Thermal Solutions KW - GEO KW - LEO Y1 - 2021 N1 - 50th International Conference on Environmental Systems, 12-15 July 2021, held virtually PB - Texas Tech University CY - Lubbock, Tex. ER -