TY - JOUR A1 - Koch, Christopher A1 - Böhnisch, Nils A1 - Verdonck, Hendrik A1 - Hach, Oliver A1 - Braun, Carsten T1 - Comparison of unsteady low- and mid-fidelity propeller aerodynamic methods for whirl flutter applications JF - Applied Sciences N2 - Aircraft configurations with propellers have been drawing more attention in recent times, partly due to new propulsion concepts based on hydrogen fuel cells and electric motors. These configurations are prone to whirl flutter, which is an aeroelastic instability affecting airframes with elastically supported propellers. It commonly needs to be mitigated already during the design phase of such configurations, requiring, among other things, unsteady aerodynamic transfer functions for the propeller. However, no comprehensive assessment of unsteady propeller aerodynamics for aeroelastic analysis is available in the literature. This paper provides a detailed comparison of nine different low- to mid-fidelity aerodynamic methods, demonstrating their impact on linear, unsteady aerodynamics, as well as whirl flutter stability prediction. Quasi-steady and unsteady methods for blade lift with or without coupling to blade element momentum theory are evaluated and compared to mid-fidelity potential flow solvers (UPM and DUST) and classical, derivative-based methods. Time-domain identification of frequency-domain transfer functions for the unsteady propeller hub loads is used to compare the different methods. Predictions of the minimum required pylon stiffness for stability show good agreement among the mid-fidelity methods. The differences in the stability predictions for the low-fidelity methods are higher. Most methods studied yield a more unstable system than classical, derivative-based whirl flutter analysis, indicating that the use of more sophisticated aerodynamic modeling techniques might be required for accurate whirl flutter prediction. KW - Aeroelasticity KW - Flutter KW - Propeller whirl flutter KW - Unsteady aerodynamics KW - 1P hub loads Y1 - 2024 U6 - https://doi.org/10.3390/app14020850 SN - 2076-3417 VL - 14 IS - 2 SP - 1 EP - 28 PB - MDPI CY - Basel ER - TY - JOUR A1 - Ley, Wilfried A1 - Plescher, Engelbert A1 - Scholz, Artur A1 - Piepenbrock, Johannes T1 - COMPASS-1 picosatellite project / Ley, Wilfried ; Plescher, Engelbert ; Scholz, Artur ; Piepenbrock, Johannes JF - Small satellites for earth observation : digest of the 6th International symposium of the International Academy of Astronautics, Berlin, April 23 - 26, 2007 / ed. by Rainer Sandau; Hans-Peter Röser; Arnoldo Valenzuela Y1 - 2007 SN - 9783896855718 N1 - Symposium on Small Satellites for Earth Observation ; (6, 2007, Berlin) SP - 147 EP - 150 PB - Wissenschaft und Technik Verl. CY - Berlin ER - TY - JOUR A1 - Funke, Harald A1 - Börner, Sebastian A1 - Falk, F. A1 - Hendrick, P. T1 - Control system modifications and their effects on the operation of a hydrogen-fueled Auxiliary Power Unit JF - XX international symposium on air breathing engines 2011 : ISABE 2011, Gothenburg, Sweden, 12-16 September, 2011. Vol. 2. Y1 - 2011 SN - 9781618391803 N1 - 20th International Symposium on Air Breathing Engines 2011 : (ISABE 2011) : Gothenburg, Sweden, 12-16 September, 2011. SP - 929 EP - 938 PB - American Institute of Aeronautics and Astronautics CY - Reston, VA ER - TY - JOUR A1 - Börner, Sebastian A1 - Funke, Harald A1 - Hendrick, P. A1 - Recker, E. T1 - Control system modifications for a hydrogen fuelled gas-turbine JF - ISROMAC 13, 13th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, Honolulu, HI, US, Apr 4-7, 2010 Y1 - 2010 SN - 978-1-617-38848-4 SP - 665 EP - 670 PB - Curran CY - Red Hook, NY ER - TY - JOUR A1 - Bullerschen, Klaus-Gerd A1 - Wilhelmi, Herbert T1 - Cooling of arc furnace electrodes with heat pipes JF - Chemical Engineering & Technology. 14 (1991), H. 1 Y1 - 1991 SN - 0930-7516 SP - 45 EP - 53 ER - TY - JOUR A1 - Schopen, Oliver A1 - Shah, Neel A1 - Esch, Thomas A1 - Shabani, Bahman T1 - Critical quantitative evaluation of integrated health management methods for fuel cell applications JF - International Journal of Hydrogen Energy N2 - Online fault diagnostics is a crucial consideration for fuel cell systems, particularly in mobile applications, to limit downtime and degradation, and to increase lifetime. Guided by a critical literature review, in this paper an overview of Health management systems classified in a scheme is presented, introducing commonly utilised methods to diagnose FCs in various applications. In this novel scheme, various Health management system methods are summarised and structured to provide an overview of existing systems including their associated tools. These systems are classified into four categories mainly focused on model-based and non-model-based systems. The individual methods are critically discussed when used individually or combined aimed at further understanding their functionality and suitability in different applications. Additionally, a tool is introduced to evaluate methods from each category based on the scheme presented. This tool applies the technique of matrix evaluation utilising several key parameters to identify the most appropriate methods for a given application. Based on this evaluation, the most suitable methods for each specific application are combined to build an integrated Health management system. KW - Fuel cell KW - Health management system KW - Online diagnostic KW - Fault detection KW - Non-model-based Evaluation Y1 - 2024 U6 - https://doi.org/10.1016/j.ijhydene.2024.05.156 SN - 0360-3199 VL - 70 SP - 370 EP - 388 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Gerhardt, Hans Joachim A1 - Konrath, B. A1 - Lieb, R.-D. T1 - Das Drallrohr JF - HLH : Lüftung, Klima, Heizung, Sanitär, Gebäudetechnik. 56 (2005), H. 11 Y1 - 2005 SN - 1436-5103 N1 - 2. ISSN: 0017-9906 ; 3. ISSN: 1434-422X ; Zeitschrift unter 13 Z 739 in der Bibliothek SP - 91 EP - 95 ER - TY - JOUR A1 - Wittmann, Klaus A1 - Kehr, J. A1 - Willnecker, R. T1 - Decentralized Payload Operations Concept for Columbus Y1 - 2000 N1 - 51st IAF Congress, Rio de Janeiro, Brazil, Oct. 2000 ER - TY - JOUR A1 - Schmitz, Günter A1 - Damann, H. A1 - Schmit, H. J. T1 - Design and Analysis of a Waveguide Isolator with a Form-Birefringent Top Layer JF - ECOC '84 : Conference proceedings ; 10th European Conference on Optical Communication, September 3 - 6, 1984 Liederhalle Stuttgart, Federal Republic of Germany / Organized by Nachrichtentechn. Ges. im VDE (NTG). Y1 - 1984 SN - 3-8007-1383-7 SP - 42 PB - VDE-Verl. CY - Berlin [u.a.] ER - TY - JOUR A1 - Robinson, A. E. A1 - Funke, Harald A1 - Hendrick, P. T1 - Design and Testing of a Micromix Combustor With Recuperative Wall Cooling for a Hydrogen Fueled µ-Scale Gas Turbine JF - Journal of engineering for gas turbines and power Y1 - 2011 SN - 1528-8919 VL - 133 IS - 8 PB - ASME CY - New York ER - TY - JOUR 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 JF - Proceedings of the ASME Turbo Expo 2010 : presented at the 2010 ASME Turbo Expo, June 14 - 18, 2010, Glasgow, UK / sponsored by the International Gas Turbine Institute / Vol. 5: Industrial and cogeneration ; microturbines and small turbomachinery ; oil and gas applications ; wind turbine technology Y1 - 2010 SN - 978-0-7918-4400-7 N1 - GT2010-23453 ; ASME Turbo Expo ; (Glasgow) : 2010.06.14-18 SP - 587 EP - 596 PB - ASME CY - New York, NY ER - TY - JOUR A1 - Gerhardt, Hans Joachim T1 - Design methods of smoke and heat exhaust systems in construction works JF - V Mie̜dzynarodowa Konferencja Bezpieczeństwo Pożarowe Budowli, Warszawa-Miedzeszyn, 14 - 16 listopada 2005 r. = : Vth International Conference Fire Safety of Buildings / ITB ... [Ed. Mirosław Kosiorek] Y1 - 2005 SN - 83-7413-810-6 N1 - Mie̜dzynarodowa Konferencja Bezpieczeństwo Pożarowe Budowli <5, 2005, Warszawa> ; International Conference Fire Safety of Buildings <5, 2005, Warszawa-Miedzeszyn> SP - 127 EP - 140 PB - ITB CY - Warszawa ER - TY - JOUR A1 - Bindal, Gaurav A1 - Sharma, Sparsh A1 - Janser, Frank A1 - Neu, Eugen T1 - Detailed analysis of variables affecting wing kinematics of bat flight JF - SAE International Journal of Aerospace Y1 - 2013 U6 - https://doi.org/10.4271/2013-01-9003 SN - 1946-3901 VL - 6 IS - 2 SP - 811 EP - 818 ER - TY - JOUR A1 - Krämer, Stefan A1 - Daab, Dominique Jonas A1 - Müller, Brigitte A1 - Wagner, Tobias A1 - Baader, Fabian A1 - Hessel, Joana A1 - Gdalewitsch, Georg A1 - Plescher, Engelbert A1 - Dachwald, Bernd A1 - Wahle, Michael A1 - Gierse, Andreas A1 - Vetter, Rudolf A1 - Pfützenreuter, Lysan T1 - Development and flight-testing of a system to isolate vibrations for microgravity experiments on sounding rockets JF - 21st ESA Symposium on Rocket and Balloon Research Y1 - 2013 SP - 1 EP - 8 ER - TY - JOUR A1 - Funke, Harald A1 - Rönna, Uwe A1 - Robinson, A. E. T1 - Development and testing of a 10 kW diffusive micromix combustor for hydrogen-fuelled μ-scale gas turbines JF - Proceedings of ASME Turbo Expo 2008: Power for Land, Sea and Air ; GT2008 ; June 9-13, 2008, Berlin, Germany Y1 - 2008 N1 - GT2008-50418 SP - 1 EP - 8 PB - ASME CY - New York, NY ER - TY - JOUR A1 - Seifarth, Volker A1 - Goßmann, Matthias A1 - Grosse, J. O. A1 - Becker, C. A1 - Heschel, I. A1 - Artmann, Gerhard A1 - Temiz Artmann, Aysegül T1 - Development of a Bioreactor to Culture Tissue Engineered Ureters Based on the Application of Tubular OPTIMAIX 3D Scaffolds JF - Urologia Internationalis Y1 - 2015 U6 - https://doi.org/10.1159/000368419 SN - 0042-1138 VL - 2015 IS - 95 SP - 106 EP - 113 PB - Karger CY - Basel ER - TY - JOUR A1 - Trilla, Joan A1 - Grossen, Jürgen A1 - Robinson, Alexander A1 - Funke, Harald A1 - Bosschaerts, Walter A1 - Hendrick, Patrick T1 - Development of a hydrogen combustion chamber for an ultra micro gas turbine JF - PowerMEMS 2008, 8th International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications, microEMS 2008, 2nd Symposium on Micro Environmental Machine Systems, Sendai, JP, Nov 9-12, 2008 Y1 - 2008 SP - 101 EP - 104 ER - TY - JOUR A1 - Robinson, A. E. A1 - Funke, Harald A1 - Hendrick, P. A1 - Recker, E. A1 - Peirs, J. T1 - Development of a hydrogen fuelled 1 kW ultra micro gas turbine with special respect to designing, testing and mapping of the µ-scale combustor JF - IEEE International Conference on Sustainable Energy Technologies, 2008 : ICSET 2008 ; Singapore, 24 - 27 Nov. 2008. Y1 - 2008 SN - 978-1-4244-1887-9 SP - 656 EP - 660 PB - IEEE CY - Piscataway, NJ ER - TY - JOUR A1 - Funke, Harald A1 - Robinson, A. E. T1 - Development of a new test rig for a micro scale hydrogen combustion chamber JF - Proceedings of the 2nd European Conference for Aero-Space Sciences : July 1 - 6, 2007, Brussels, Belgium Y1 - 2007 N1 - European Conference for Aerospace Sciences <2, 2007, Brüssel> ; EUCASS <2, 2007, Brüssel> ; Paper No. 22 SP - 1 EP - 8 PB - - ER - TY - JOUR A1 - Hailer, Benjamin A1 - Weber, Tobias A1 - Neveling, Sebastian A1 - Dera, Samuel A1 - Arent, Jan-Christoph A1 - Middendorf, Peter T1 - Development of a test device to determine the frictional behavior between honeycomb and prepreg layers under realistic manufacturing conditions JF - Journal of Sandwich Structures & Materials N2 - In the friction tests between honeycomb with film adhesive and prepreg, the relative displacement occurs between the film adhesive and the prepreg. The film adhesive does not shift relative to the honeycomb. This is consistent with the core crush behavior where the honeycomb moves together with the film adhesive, as can be seen in Figure 2(a). The pull-through forces of the friction measurements between honeycomb and prepreg at 1 mm deformation are plotted in Figure 17(a). While the friction at 100°C is similar to the friction at 120°C, it decreases significantly at 130°C and exhibits a minimum at 140°C. At 150°C, the friction rises again slightly and then sharply at 160°C. Since the viscosity of the M18/1 prepreg resin drops significantly before it cures [23], the minimum friction at 140°C could result from a minimum viscosity of the mixture of prepreg resin and film adhesive before the bond subsequently cures. Figure 17(b) shows the mean value curve of the friction measurements at 140°C. The error bars, which represent the standard deviation, reveal the good repeatability of the tests. The force curve is approximately horizontal between 1 mm and 2 mm. The friction then slightly rises. As with interlaminar friction measurements, this could be due to the fact that resin is removed by friction and the proportion of boundary lubrication increases. Figure 18 shows the surfaces after the friction measurement. The honeycomb cell walls are clearly visible in the film adhesive. There are areas where the film adhesive is completely removed and the carrier material of the film adhesive becomes visible. In addition, the viscosity of the resin changes as the curing progresses during the friction test. This can also affect the force-displacement curve. Y1 - 2020 U6 - https://doi.org/10.1177/1099636220923986 SN - 1530-7972 IS - Volume 23, Issue 7 SP - 3017 EP - 3043 PB - Sage CY - London ER -