TY - THES A1 - Kowalski, Julia T1 - Two-phase Modeling of Debris Flows Y1 - 2008 SN - 978-3-86664-524-0 N1 - Diss., Eidgenössische Technische Hochschule ETH Zürich, Nr. 17827, 2008 PB - Mensch und Buch CY - Berlin ER - TY - GEN A1 - Kowalski, Julia T1 - Dynamics of Granular Material Avalanches and Numerical Approximations of Savage-Hutter Models Y1 - 2004 N1 - Diploma Thesis, University of Augsburg ER - TY - CHAP A1 - Kowalski, Julia T1 - Numerical Debris Flow Simulation T2 - Schweizer Numerik Kolloquium : Book of Abstracts 12. April 2006 Y1 - 2006 ER - TY - CHAP A1 - Kowalski, Julia A1 - Bartelt, Perry A1 - McElwaine, J. T1 - Two-phase debris flow modeling T2 - Geophysical Research Abstracts Y1 - 2007 N1 - A-08119 ER - TY - CHAP A1 - Kowalski, Julia A1 - Bugnion, Louis T1 - An extended shallow flow theory for natural debris flows Y1 - 2009 N1 - 2009 Portland GSA Annual Meeting (18-21 October 2009); Geological Society of America VL - 41 IS - 7 SP - 609 EP - 609 ER - TY - JOUR A1 - Kowalski, Julia A1 - Linder, Peter A1 - Zierke, S. A1 - Wulfen, B. van A1 - Clemens, J. A1 - Konstantinidis, K. A1 - Ameres, G. A1 - Hoffmann, R. A1 - Mikucki, J. A1 - Tulaczyk, S. A1 - Funke, O. A1 - Blandfort, D. A1 - Espe, Clemens A1 - Feldmann, Marco A1 - Francke, Gero A1 - Hiecker, S. A1 - Plescher, Engelbert A1 - Schöngarth, Sarah A1 - Dachwald, Bernd A1 - Digel, Ilya A1 - Artmann, Gerhard A1 - Eliseev, D. A1 - Heinen, D. A1 - Scholz, F. A1 - Wiebusch, C. A1 - Macht, S. A1 - Bestmann, U. A1 - Reineking, T. A1 - Zetzsche, C. A1 - Schill, K. A1 - Förstner, R. A1 - Niedermeier, H. A1 - Szumski, A. A1 - Eissfeller, B. A1 - Naumann, U. A1 - Helbing, K. T1 - Navigation technology for exploration of glacier ice with maneuverable melting probes JF - Cold Regions Science and Technology N2 - The Saturnian moon Enceladus with its extensive water bodies underneath a thick ice sheet cover is a potential candidate for extraterrestrial life. Direct exploration of such extraterrestrial aquatic ecosystems requires advanced access and sampling technologies with a high level of autonomy. A new technological approach has been developed as part of the collaborative research project Enceladus Explorer (EnEx). The concept is based upon a minimally invasive melting probe called the IceMole. The force-regulated, heater-controlled IceMole is able to travel along a curved trajectory as well as upwards. Hence, it allows maneuvers which may be necessary for obstacle avoidance or target selection. Maneuverability, however, necessitates a sophisticated on-board navigation system capable of autonomous operations. The development of such a navigational system has been the focal part of the EnEx project. The original IceMole has been further developed to include relative positioning based on in-ice attitude determination, acoustic positioning, ultrasonic obstacle and target detection integrated through a high-level sensor fusion. This paper describes the EnEx technology and discusses implications for an actual extraterrestrial mission concept. Y1 - 2016 U6 - http://dx.doi.org/10.1016/j.coldregions.2015.11.006 SN - 0165-232X IS - 123 SP - 53 EP - 70 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Kowalski, Julia A1 - McArdell, B. W. A1 - Bartelt, Perry T1 - A comparison of two approaches to modeling multiphase gravity currents T2 - Geophysical Research Abstracts Y1 - 2006 N1 - A-08738 VL - 8 ER - TY - CHAP A1 - Kowalski, Julia A1 - McElwaine, J. T1 - Two-phase debris flow modeling T2 - Geophysical Research Abstracts Y1 - 2008 N1 - A-01048 ER - TY - JOUR A1 - Kowalski, Julia A1 - McElwaine, Jim N. T1 - Shallow two-component gravity-driven flows with vertical variation JF - Journal of Fluid Mechanics Y1 - 2013 SN - 0022-1120 VL - 714 SP - 434 EP - 462 PB - Cambridge Univ. Press CY - Cambridge ER - TY - CHAP A1 - Kreyer, Jörg A1 - Esch, Thomas T1 - Simulation Tool for Predictive Control Strategies for an ORCSystem in Heavy Duty Vehicles T2 - European GT Conference 2017 N2 - Scientific questions - How can a non-stationary heat offering in the commercial vehicle be used to reduce fuel consumption? - Which potentials offer route and environmental information among with predicted speed and load trajectories to increase the efficiency of a ORC-System? Methods - Desktop bound holistic simulation model for a heavy duty truck incl. an ORC System - Prediction of massflows, temperatures and mixture quality (AFR) of exhaust gas Y1 - 2017 N1 - European GT Conference 2017, 9.-10. Oktober 2017, Frankfurt a.M. ER - TY - JOUR A1 - Kreyer, Jörg A1 - Müller, Marvin A1 - Esch, Thomas T1 - A Calculation Methodology for Predicting Exhaust Mass Flows and Exhaust Temperature Profiles for Heavy-Duty Vehicles JF - SAE International Journal of Commercial Vehicles N2 - The predictive control of commercial vehicle energy management systems, such as vehicle thermal management or waste heat recovery (WHR) systems, are discussed on the basis of information sources from the field of environment recognition and in combination with the determination of the vehicle system condition. In this article, a mathematical method for predicting the exhaust gas mass flow and the exhaust gas temperature is presented based on driving data of a heavy-duty vehicle. The prediction refers to the conditions of the exhaust gas at the inlet of the exhaust gas recirculation (EGR) cooler and at the outlet of the exhaust gas aftertreatment system (EAT). The heavy-duty vehicle was operated on the motorway to investigate the characteristic operational profile. In addition to the use of road gradient profile data, an evaluation of the continuously recorded distance signal, which represents the distance between the test vehicle and the road user ahead, is included in the prediction model. Using a Fourier analysis, the trajectory of the vehicle speed is determined for a defined prediction horizon. To verify the method, a holistic simulation model consisting of several hierarchically structured submodels has been developed. A map-based submodel of a combustion engine is used to determine the EGR and EAT exhaust gas mass flows and exhaust gas temperature profiles. All simulation results are validated on the basis of the recorded vehicle and environmental data. Deviations from the predicted values are analyzed and discussed. Y1 - 2020 U6 - http://dx.doi.org/10.4271/02-13-02-0009 SN - 1946-3928 VL - 13 IS - 2 SP - 129 EP - 143 PB - SAE International CY - Warrendale, Pa. ER - TY - CHAP A1 - Kreyer, Jörg A1 - Müller, Marvin A1 - Esch, Thomas T1 - A Map-Based Model for the Determination of Fuel Consumption for Internal Combustion Engines as a Function of Flight Altitude T2 - Deutscher Luft- und Raumfahrtkongress 2019, „Luft- und Raumfahrt – technologische Brücke in die Zukunft“, Darmstadt, 30. September bis 2. Oktober 2019 Y1 - 2020 U6 - http://dx.doi.org/10.25967/490162 PB - Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V CY - Bonn ER - TY - CHAP A1 - Kroniger, Daniel A1 - Horikawa, Atsushi A1 - Funke, Harald A1 - Pfäffle, Franziska T1 - Numerical investigation of micromix hydrogen flames at different combustor pressure levels T2 - Proceedings of the International Conference on Power Engineering 2021 N2 - This study investigates the influence of pressure on the temperature distribution of the micromix (MMX) hydrogen flame and the NOx emissions. A steady computational fluid dynamic (CFD) analysis is performed by simulating a reactive flow with a detailed chemical reaction model. The numerical analysis is validated based on experimental investigations. A quantitative correlation is parametrized based on the numerical results. We find, that the flame initiation point shifts with increasing pressure from anchoring behind a downstream located bluff body towards anchoring upstream at the hydrogen jet. The numerical NOx emissions trend regarding to a variation of pressure is in good agreement with the experimental results. The pressure has an impact on both, the residence time within the maximum temperature region and on the peak temperature itself. In conclusion, the numerical model proved to be adequate for future prototype design exploration studies targeting on improving the operating range. KW - Gas turbine combustion KW - Hydrogen KW - NOx emissions KW - Flame temperature KW - Flame residence time Y1 - 2021 N1 - Proceedings of the International Conference on Power Engineering 2021 (ICOPE-2021). October 17 - 21, 2021. Kobe, Japan (Online) ER - TY - CHAP A1 - Kroniger, Daniel A1 - Horikawa, Atsushi A1 - Funke, Harald A1 - Pfäffle, Franziska A1 - Kishimoto, Tsuyoshi A1 - Okada, Koichi T1 - Experimental and numerical investigation on the effect of pressure on micromix hydrogen combustion T2 - ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition // Volume 3A: Combustion, Fuels, and Emissions N2 - The micromix (MMX) combustion concept is a DLN gas turbine combustion technology designed for high hydrogen content fuels. Multiple non-premixed miniaturized flames based on jet in cross-flow (JICF) are inherently safe against flashback and ensure a stable operation in various operative conditions. The objective of this paper is to investigate the influence of pressure on the micromix flame with focus on the flame initiation point and the NOx emissions. A numerical model based on a steady RANS approach and the Complex Chemistry model with relevant reactions of the GRI 3.0 mechanism is used to predict the reactive flow and NOx emissions at various pressure conditions. Regarding the turbulence-chemical interaction, the Laminar Flame Concept (LFC) and the Eddy Dissipation Concept (EDC) are compared. The numerical results are validated against experimental results that have been acquired at a high pressure test facility for industrial can-type gas turbine combustors with regard to flame initiation and NOx emissions. The numerical approach is adequate to predict the flame initiation point and NOx emission trends. Interestingly, the flame shifts its initiation point during the pressure increase in upstream direction, whereby the flame attachment shifts from anchoring behind a downstream located bluff body towards anchoring directly at the hydrogen jet. The LFC predicts this change and the NOx emissions more accurately than the EDC. The resulting NOx correlation regarding the pressure is similar to a non-premixed type combustion configuration. KW - NOx emissions KW - hydrogen KW - combustor KW - gas turbine Y1 - 2021 U6 - http://dx.doi.org/10.1115/GT2021-58926 N1 - ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition. June 7–11, 2021. Virtual, Online. Paper No: GT2021-58926, V03AT04A025 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 - BOOK A1 - Köhler, Bernd T1 - Werkstofftechnologie der Luft- und Raumfahrt. Teil 3: HT-Superlegierungen Y1 - 1990 SN - 3-89653-863-2 PB - Mainz CY - Aachen ER - TY - BOOK A1 - Köhler, Bernd T1 - Werkstofftechnologie der Luft- und Raumfahrt. Teil 3: HT-Superlegierungen. -2. Auflage Y1 - 2001 SN - 3-89653-863-2 PB - Mainz CY - Aachen ER - TY - BOOK A1 - Köhler, Bernd T1 - Werkstofftechnologie der Luft- und Raumfahrt. Teil 4 : Sonderwerkstoffe. -2. Aufl. Y1 - 1990 SN - 3-89653-864-6 PB - Mainz CY - Aachen ER - TY - BOOK A1 - Köhler, Bernd T1 - Werkstofftechnologie der Luft- und Raumfahrt. Teil 4 : Sonderwerkstoffe. -4. Aufl. Y1 - 2001 SN - 3-89653-864-6 PB - Mainz CY - Aachen ER - TY - BOOK A1 - Köhler, Bernd T1 - Werkstofftechnologie der Luft- und Raumfahrt. Teil 1 : Grundlagen. -4. Aufl. Y1 - 2001 SN - 3-89653-861-6 PB - Mainz CY - Aachen ER -