TY - CHAP A1 - Neef, Matthias T1 - Innerstädtische Nutzung von Kleinwindkraftanlagen: Potentiale und Hürden T2 - Mülheimer Initiative für Klimaschutz, 06.05.2013 Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-21017 CY - Mülheim an der Ruhr ER - TY - JOUR A1 - Laux, Christoph A1 - Gotter, Andreas A1 - Eckert, Frank A1 - Neef, Matthias T1 - Experimental results of a low-pressure steam Rankine cycle with a novel water lubricated radial inflow turbine for the waste heat utilization of internal combustion engines JF - Energy Conversion and Management Y1 - 2022 U6 - https://doi.org/10.1016/j.enconman.2022.116265 SN - 0196-8904 VL - 271 PB - Elsevier ER - TY - RPRT A1 - Adam, Mario A1 - Dreher, Martina A1 - Ebling, Dirk A1 - Knopp, Reinhold A1 - Neef, Matthias A1 - Niess, Robert A1 - Pohl, Tobias A1 - Stahl, Wilhelm A1 - van Rießen, Anne A1 - Waldow, Friederike A1 - Weber, Konradin A1 - Weis, Stephanie T1 - LUST Forschungsprojekt - lebenswerte und umweltgerechte Stadt N2 - LUST (lebenswerte und umweltgerechte Stadt) ist ein interdisziplinäres Projekt der Fachbereiche Architektur, Maschinenbau und Verfahrenstechnik sowie Kultur- und Sozialwissenschaften der Hochschule Düsseldorf. Mittelpunkt des Projektes ist die fachübergreifende Entwicklung neuer Konzepte für eine lebenswerte und umweltgerechte Stadt. Es wurde gefördert vom Land Nordrhein-Westfalen im Rahmen des Programms „FH Struktur“. N2 - LUST (Liveable and environment-friendly Urban SiTe) is an interdisciplinary project of the faculties of Architecture, Mechanical and Process Engineering as well as Social Studies and Cultural Sciences at the University of Applied Sciences Düsseldorf. The four-year (2013 – 2016) project is funded by the Ministry of Innovation, Science and Research of North Rhine–Westphalia. The aim is to develop holistic, new concepts for a liveable and environmentally friendly city in a multidisciplinary manner. KW - Stadtentwicklung KW - lebenswert KW - umweltgerecht KW - substainable urban development KW - environmentally friendly KW - liveable Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-11458 SN - 978-3-941334-43-4 CY - Düsseldorf ER - TY - JOUR A1 - Neef, Matthias A1 - Zielke, Thomas A1 - Fussenecker, Claudia T1 - „Engineering Conferences“: Wissenschaftlich Kommunizieren im Master JF - Die Neue Hochschule Y1 - 2017 VL - 58 IS - 3 ER - TY - CHAP A1 - Helm, Peter A1 - Spliethoff, Hartmut A1 - Neef, Matthias T1 - Closing the Gap: Measuring Bristle Blow Down of Brush Seals T2 - 19 th International Conference on Fluid Sealing, Poitiers Y1 - 2007 CY - Poitiers ER - TY - CHAP A1 - Neef, Matthias A1 - Hepermann, Florian A1 - Sürken, Norbert A1 - Schettel, Joachim T1 - Brush Seal Porosity Modeling: Applicability and Limitations T2 - ETC7 – 7th Conference on Turbomachinery, Athens Y1 - 2007 CY - Athens ER - TY - CHAP A1 - Neef, Matthias A1 - Hummel, Dietrich T1 - Euler solutions for a finite-span flapping wing T2 - "Fixed, flapping and rotary wing vehicles at very low Reynolds numbers, Notre Dame, Indiana, USA Y1 - 2000 ER - TY - CHAP A1 - Dubberke, Frithjof A1 - Priebe, Klaus-Peter A1 - Vrabec, Jadran A1 - Neef, Matthias A1 - Rödder, Maximilian T1 - Thermodynamic simulation and experimental validation of a cascaded two-stage organic Rankine cycle T2 - ASME ORC 2015, Brussels KW - simulation Y1 - 2015 CY - Brussels ER - TY - JOUR A1 - Baier, André A1 - Neef, Matthias T1 - Studierende lehren und lernen sozial-ökologische Verantwortung JF - Die Neue Hochschule KW - Verantwortung Y1 - 2019 VL - 60 IS - 5 SP - 8 EP - 11 ER - TY - GEN A1 - Frank, Lena A1 - Rödder, Maximilian A1 - Neef, Matthias A1 - Adam, Mario T1 - energiBUS4home – Integration von Haushaltsgeräten in ein multifunktionales Wärmepumpensystem T2 - KI Kälte Luft Klimatechnik KW - energiBUS4home Y1 - 2020 SN - 1865-5432 VL - 56 IS - 8/9 SP - 41 EP - 45 PB - Hüthig ER - TY - JOUR A1 - Frank, Lena A1 - Rödder, Maximilian A1 - Neef, Matthias A1 - Adam, Mario T1 - Heating, Ventilation, Domestic Appliances – an Energy Integrated System Concept for the Household of the Future JF - Energy Y1 - 2021 U6 - https://doi.org/10.1016/j.energy.2021.121303 SN - 0360-5442 VL - 234 PB - Elsevier ER - TY - GEN A1 - Frank, Lena A1 - Rödder, Maximilian A1 - Neef, Matthias A1 - Adam, Mario T1 - Heizung, Lüftung, Weiße Ware – Ein integriertes Systemkonzept für das Haus der Zukunft T2 - KKA – Kälte Klima Aktuell KW - energiBUS4home Y1 - 2018 SN - 0722-4605 VL - 37 IS - 4 SP - 42 EP - 47 PB - Bauverl. BV ER - TY - JOUR A1 - Rödder, Maximilian A1 - Frank, Lena A1 - Kirschner, Daniel A1 - Neef, Matthias A1 - Adam, Mario T1 - EnergiBUS4home – Sustainable energy resourcing in low-energy buildings JF - Energy KW - energiBUS4home Y1 - 2018 U6 - https://doi.org/10.1016/j.energy.2018.06.145 N1 - PII: S0360544218312106 VL - 159 SP - 638 EP - 647 PB - Elsevier ER - TY - CHAP A1 - Neef, Matthias A1 - aus der Wiesche, Stefan ED - aus der Wiesche, Stefan ED - Joos, Franz T1 - Aufbau und Wirkungsweise von Dampfturbinen: Grundlagen, Konstruktion, Betrieb T2 - Handbuch Dampfturbinen KW - Turbinen Y1 - 2018 SN - 978-3-658-20629-1 U6 - https://doi.org/10.1007/978-3-658-20630-7_2 SP - 27 EP - 83 PB - Springer Vieweg CY - Wiesbaden ER - TY - CHAP A1 - Frank, Lena A1 - Rödder, Maximilian A1 - Neef, Matthias A1 - Adam, Mario T1 - Heizung, Lüftung, Weiße Ware – ein integriertes Systemkonzept für das Haus der Zukunft T2 - Deutsche Kälte- und Klimatagung 2017 Bremen KW - Heizung KW - EnerTEG Y1 - 2017 SN - 9783932715938 SP - 1028 EP - 1041 CY - Stuttgart ER - TY - RPRT A1 - Neef, Matthias A1 - Laux, Christoph T1 - Optimierung des elektrischen Nutzungsgrades eines Blockheizkraftwerks durch Abwärmeverwertung in einem nachgeschalteten Dampfkraftprozess N2 - Abschlussbericht Förderung: Bundesministerium für Bildung und Forschung (BMBF) Förderkennzeichen: 03FH006I2 Projektzeitraum: 31.08.2012 -31.08.2015 Y1 - 2016 U6 - https://doi.org/10.2314/GBV:867675985 CY - Düsseldorf ER - TY - CHAP A1 - Neef, Matthias A1 - Hummel, Dietrich ED - Mueller, Thomas J. T1 - Euler Solutions for a Finite-Span Flapping Wing T2 - Fixed and Flapping Wing Aerodynamics for Micro Air Vehicle Applications Y1 - 2001 SN - 978-1-56347-517-7 U6 - https://doi.org/10.2514/5.9781600866654.0429.0451 VL - 16 SP - 429 EP - 451 PB - American Institute of Aeronautics and Astronautics CY - Reston, VA ER - TY - CHAP A1 - Neef, Matthias A1 - André, Baier T1 - Blue Engineering: Ingenieur_innen mit ökologischer und sozialer Verantwortung - ein Studierenden-getriebenes, modulares Seminar-Konzept T2 - DGHD-Jahrestagung KW - Poster Y1 - 2019 UR - https://www.researchgate.net/publication/331327194_Blue_Engineering_Ingenieur_innen_mit_okologischer_und_sozialer_Verantwortung_-_ein_Studierenden-getriebenes_modulares_Seminar-Konzept PB - Universität Leipzig CY - Leipzig ER - TY - CHAP A1 - Neef, Matthias A1 - Hummel, D. ED - Krause, Egon ED - Jäger, Willi T1 - Euler and Navier-Stokes Solutions for Flapping Wing Propulsion T2 - High Performance Computing in Science and Engineering ’01 KW - Wing Motion KW - Computational Fluid Dynamics KW - High Performance Computing KW - Thrust Coefficient Y1 - 2002 SN - 978-3-642-62719-4 U6 - https://doi.org/10.1007/978-3-642-56034-7_37 VL - 30 SP - 386 EP - 395 PB - Springer CY - Berlin ER - TY - CHAP A1 - Rödder, Maximilian A1 - Frank, Lena A1 - Kirschner, Daniel A1 - Neef, Matthias A1 - Adam, Mario ED - The International Centre for Sustainable Development of Energy, Water and Environment Systems, T1 - EnergiBUS4home – Sustainable energy resourcing in low-energy buildings T2 - 12th Conference on Sustainable Development of Energy, Water and Environment Systems, 04.-08.10.2017, Dubrovnik KW - energiBUS4home Y1 - 2017 ER - TY - CHAP A1 - Windte, Jan A1 - Radespiel, Rolf A1 - Neef, Matthias ED - Kroll, Norbert ED - Fassbender, Jens K. T1 - Aerodynamic Analysis of Flapping Airfoil Propulsion at Low Reynolds Numbers T2 - MEGAFLOW - Numerical Flow Simulation for Aircraft Design KW - Lift Curve KW - Chord Length KW - Pitch Motion KW - Laminar Separation Bubble KW - Combine Motion Y1 - 2005 SN - 978-3-540-24383-0 U6 - https://doi.org/10.1007/3-540-32382-1_21 VL - NNFM, 89 SP - 299 EP - 313 PB - Springer-Verlag CY - Berlin, Heidelberg ER - TY - CHAP A1 - Neef, Matthias A1 - Zielke, Thomas A1 - Fussenecker, Claudia ED - Danish Network for Engineering Education, T1 - Engineering Conferences - An Innovative Course for Master Students in Engineering T2 - Exploring Teaching for Active Learning in Engineering Education N2 - This poster summarizes a few facts, figures and resources related to the Master course ”Engineering Conferences”. KW - Poster Y1 - 2017 SN - 978-87-998898-1-5 PB - Danish Network for Engineering Education (IUPN) CY - Odense ER - TY - CHAP A1 - Rödder, Maximilian A1 - Spiegel, Thomas A1 - Frank, Lena A1 - Neef, Matthias A1 - Adam, Mario ED - Großmann, Uwe ED - Kunold, Ingo T1 - Integration eines multifunktionalen Wärmepumpensystems als Hardware-in-the-Loop in ein Niederspannungsnetzmodell T2 - Smart Energy and Systems 2019: Digitalisierung - Anwendungen in Technik und Industriegesellschaft, 10. Fachtagung, 04.-05.11.2019, Dortmund KW - energiBUS4home Y1 - 2019 SP - 70 EP - 77 PB - vwh Verlag Werner Hülsbusch Fachverlag für Medientechnik und -wirtschaft CY - Glückstadt ER - TY - CHAP A1 - Kramer, Tim A1 - Lerner, Igor A1 - Sacher, Patrick A1 - Neef, Matthias A1 - Baier, André ED - Dederichs-Koch, Andrea ED - Mohnert, Andrea ED - Kammasch, Gudrun T1 - Blue Engineering: Was ist das und wie gelingt die Implementierung an meiner Hochschule? T2 - Diversität und Kulturelle Vielfalt - Differenzieren, Individualisieren - oder Integrieren? Wege zu technischer Bildung : Referate der 13. Ingenieurpädagogischen Regionaltagung 2018 and der Hochschule Bochum vom 7.-9. Juni 2018 KW - Blue Engineering KW - Diversität Y1 - 2018 SN - 978-3-9818728-2-8 PB - Ingenieur-Pädagogische Wissensgesellschaft (IPW) CY - Berlin ER - TY - CHAP A1 - Rödder, Maximilian A1 - Laux, Christoph A1 - Neef, Matthias T1 - Systematic fluid selection in early stages of ORC design: a practical engineering approach T2 - Proceedings of the ASME Turbo Expo: Turbine Technical Conference and Exposition - 2015 : presented at the ASME 2015 Turbo Expo: Turbine Technical Conference and Exposition, June 15 - 19, 2015, Montreal, Quebec, Canada / sponsored by the International Gas Turbine Institute Y1 - 2015 SN - 978-0-7918-5667-3 VL - 3: Coal, biomass and alternative fuels - cycle innovations - electric power - industrial and cogeneration PB - International Gas Turbine Institute (ASME) CY - New York ER - TY - CHAP A1 - Hurd, Paul A1 - Truckenmueller, Frank A1 - Thamm, Norbert A1 - Pollak, Helmut A1 - Neef, Matthias A1 - Deckers, Mathias T1 - Modern Reaction HP/IP Turbine Technology Advances and Experiences T2 - Proceedings of the ASME Power Conference - 2005 : includes papers from the 2005 International Conference on Power Engineering (ICOPE) ; presented at the 2005 ASME Power Conference, April 5 - 7, 2005, Chicago, Illinois, USA Y1 - 2005 UR - https://asmedigitalcollection.asme.org/POWER/proceedings/POWER2005/41820/425/311927 SN - 0-7918-4182-0 U6 - https://doi.org/10.1115/PWR2005-50085 SP - 425 EP - 435 PB - ASME CY - New York ER - TY - JOUR A1 - Wolter, Nina A1 - Zekorn, Thomas A1 - Neef, Matthias T1 - Stationäre thermodynamische Prozesssimulationen am Beispiel eines Industriekraftwerks JF - BWK: das Energie-Fachmagazin N2 - Um bauliche Veränderungen in bestehenden Kraftwerksprozessen auf ihre Wirkungsweise untersuchen und thermodynamisch beziehungsweise wirtschaftlich bewerten zu können, werden thermische Kraftwerksprozesse mit geeigneter Simulationssoftware abgebildet und in verschiedenen Detaillierungsstufen ausgelegt oder nachgerechnet. Im Folgenden wird ein Weg aufgezeigt, wie mit Hilfe einer stationären Simulationssoftware die Gesamtjahresbilanz eines Kraftwerks vorausberechnet werden kann. Mit Hilfe von Prozessdaten aus Vorjahren wird nachgewiesen, dass das Berechnungsmodell das bestehende Kraftwerk mit einer Abweichung von weniger als drei Prozent bezüglich erzeugter elektrischer Leistung und Brennstoffeinsatz und bei bekannter Dampfproduktion abbilden kann. Das so verifizierte Modell kann zur Untersuchung von Zubaumaßnahmen oder Veränderungen im Kraftwerksprozess eingesetzt werden. KW - Energiebilanz KW - Kraftwerk Y1 - 2016 VL - 68 IS - 6 SP - 6 EP - 10 ER - TY - GEN A1 - Frank, Lena A1 - Rödder, Maximilian A1 - Neef, Matthias A1 - Adam, Mario T1 - Heizung, Lüftung, Weiße Ware - Ein integriertes Systemkonzept für das Haus der Zukunft T2 - KI Kälte Luft Klimatechnik N2 - In energieeffizienten Gebäuden spielt der Bedarf an Energie für die Raumheizung gegenüber der benötigten Energie für Warmwasser und zum Antrieb elektrischer Geräte eine zusehends untergeordnete Rolle. Die thermische Energie für elektrische Haushalts­geräte, wie Waschmaschine, Kühlschrank etc., wird für gewöhnlich dezentral im Gerät erzeugt. Vor diesem Hintergrund ist das Ziel eines Forschungsprojekts der Bau und der Test eines Funktionsmusters zur funktionalen und energetischen Kopplung der Haushaltsgeräte und der Heizungs- und Lüftungstechnik des Gebäudes. Grundgedanke dabei ist die Nutzung von Synergien bei Komponenten und Wärmeströmen, wie der Wärmepumpe als Kälteaggregat für den Kühlschrank, und die effiziente Nutzung von Abwärme der Haushaltsgeräte für die Warmwasserbereitung und Raumheizung. KW - Energieeffizienz KW - energiBUS4home Y1 - 2018 SN - 1865-5432 VL - 54 IS - 11 SP - 50 EP - 56 PB - Hüthig ER - TY - CHAP A1 - Völker, Lutz A1 - Casey, Michael A1 - Neef, Matthias A1 - Stüer, Heinrich T1 - The Flow Field and Performance of a Model Low Pressure Steam Turbine T2 - 6th European Conference on Turbomachinery - Fluid Dynamics and Thermodynamics : conference proceedings; 7-11 March 2005, Lille, France N2 - A 3-stage model of a low pressure steam turbine has been equipped with extensive instrumentation to assess aerodynamic performance and for validation of numerical methods. Emphasis was placed on detailed measurements at the inlet and exit of the last stage guide vane. Two configurations were examined – the first used a guide vane with lean in the last stage and a the second used a guide vane combining both lean and sweep. The experimental results from the two configurations have been compared with data from various design methods, ranging from through-flow to 3D multistage viscous simulations with mixing planes. Despite the challenges in modelling complex rotating blades in a wet steam environment, good agreement between the numerical and experimental results was obtained, and the new stator vane combining lean and sweep achieved the desired increase in reaction at the hub section. Y1 - 2005 CY - Lille ER - TY - CHAP A1 - Neef, Matthias A1 - Zielke, Thomas A1 - Fussenecker, Claudia ED - Danish Network for Engineering Education, T1 - Engineering Conferences - An Innovative Course for Master Students in Engineering T2 - Exploring Teaching for Active Learning in Engineering Education N2 - A course called "Engineering Conferences" is presented that the authors have developed and installed as a mandatory part of the curriculum in Master programs for engineering students. The idea is to go beyond teaching the standards of academic writing and skills for working with scientific publications. By using a learner-centered approach, we get the students engaged in typical activities around an active attendance of a real conference. They write a paper complying with common academic standards, submit the paper and review submissions of their fellow students. Students also produce a poster and have to defend it in a poster session held publicly on campus. In this article, we present our rationale to develop the course and our results from the first semester teaching this course. This includes the presentation of useful resources for teaching and organizing scientific publishing as well as our reflected learning experience regarding the student's understanding of significance for scientific publishing. KW - Engineering Conference Y1 - 2017 SN - 978-87-998898-1-5 SP - 13 EP - 24 CY - Odense ER - TY - JOUR A1 - Dubberke, Frithjof H. A1 - Linnemann, Matthias A1 - Abbas, Wameedh Khider A1 - Baumhögger, Elmar A1 - Priebe, Klaus-Peter A1 - Roedder, Maximilian A1 - Neef, Matthias A1 - Vrabec, Jadran T1 - Experimental setup of a cascaded two-stage organic Rankine cycle JF - Applied Thermal Engineering N2 - In combination with a bottoming cycle, operated with a pure fluid in transcritical mode, the usage of a zeotropic mixture as a working fluid appears to be exergetically favorable for power cycle efficiency in cascaded two-stage organic Rankine cycles (CORC). A CORC is set up and initially tested with cyclopentane and propane as working fluids in its high temperature and low temperature cycle, respectively. A thermal oil cycle serves as the heat source and is powered electrically with a maximum heat flow of 158 kW. The design of this experimental setup allows for a rapid replacement of individual components and for a wide range of conditions in terms of fluids and thermodynamic states. The components of all cycles and the measurement and control technology are described in detail. A testing procedure is presented, followed by a discussion of the measurement results, where it is shown that the intended concept of two cascaded organic Rankine cycles is operational and that the measured data are consistent. KW - organic Rankine cycle KW - cascade KW - multicomponent working fluid KW - temperature-glide KW - pinch point KW - exergetice efficiency Y1 - 2018 U6 - https://doi.org/10.1016/j.applthermaleng.2017.11.137 VL - 131 SP - 958 EP - 964 PB - Elsevier ER - TY - CHAP A1 - Neef, Matthias A1 - Sulda, Erik A1 - Sürken, Norbert A1 - Walkenhorst, Jan T1 - Design Features and Performance Details of Brush Seals for Turbine Applications T2 - Proceedings of the ASME Turbo Expo 2006 : presented at the 2006 ASME Turbo Expo, May 6 - 11, 2006, Barcelona, Spain N2 - Adaptive and contacting seals such as brush seals have been successfully applied to turbomachinery for several years. In large steam turbine applications, however, various challenges still persist. Special focus is directed at the long-term performance and longevity of brushes on conventional spring-backed seal segments in steam turbines. This issue is particularly related to wear during startup conditions. This paper discusses the results of wear tests, derived from simulated transient turbine behavior, where the resultant seal leakage under steady state conditions is monitored. It is shown that the brush seal is significantly capable of adapting to varying operating conditions, but exhibits a degree of performance degradation during the initial startups. Together with previously reported mid-term wear data and an experience based long-term phenomenological approach a general model for brush seal performance degradation is developed. This model can be used for performance prediction and exerts influence on brush seal design. Y1 - 2006 SN - 0-7918-4238-X U6 - https://doi.org/10.1115/GT2006-90404 VL - 3 SP - 1385 EP - 1392 PB - ASME CY - New York ER - TY - CHAP A1 - Jones, Kevin A1 - Castro, Breno A1 - Mahmoud, Osama A1 - Pollard, S. A1 - Platzer, Max A1 - Neef, Matthias A1 - Gonet, K. A1 - Hummel, D. T1 - A collaborative numerical and experimental investigation of flapping-wing propulsion T2 - 40th AIAA Aerospace Sciences Meeting & Exhibit N2 - An international, collaborative investigation is undertaken to evaluate the relative merits and limitations of various numerical methods and experimental measurement techniques, specifically for the analysis of flapping-wing propulsion. A finite aspect-ratio configuration is extensively investigated, both quantitatively and qualitatively, in a low-speed wind tunnel. Direct force measurements are made, as well as time-accurate and time-averaged laser Doppler velocimetry and unsteady flow visualization. The reduced frequency, mean angle of attack, aspect ratio and Reynolds number are varied in the experiments. The experiment is numerically simulated using flatplate theory, two and three-dimensional panel codes, and two and three-dimensional Euler and Navier- Stokes solvers. The ability of each of the methods to capture important aspects of the flow physics are evaluated through comparisons with each other and the experimental data. Additionally, the comparisons indicate areas where further research is needed. The collaborative effort provides a survey of available capabilities and provides a fixed set of flappingwing data for others to compare against. Y1 - 2002 UR - http://arc.aiaa.org/doi/book/10.2514/MASM02 U6 - https://doi.org/10.2514/6.2002-706 PB - American Institute of Aeronautics and Astronautics CY - Reston, Virigina ER - TY - CHAP A1 - Zielke, Thomas A1 - Neef, Matthias A1 - Fussenecker, Claudia T1 - Teaching Engineering Conferences T2 - Proceedings of the Canadian Engineering Education Association (CEEA) Conference N2 - This article is on a university course called Engineering Conferences. It has been developed by the authors and installed as a mandatory part of the curriculum in three master’s degree programs for engineering students. The participants of the course are postgraduates with different nationalities, mostly German, and different technical backgrounds. They study Mechanical Engineering, Simulation and Experimental Technology, or International Business Engineering. The basic idea of the course concept goes far beyond simply teaching the standards of academic writing and skills for using scientific publications. By using a learnercentered approach, the students get engaged in typical activities around an active attendance of a real conference. Students learn to locate the field of their bachelor thesis or project report in the world of research communities, scientific journals and engineering conferences. They learn about conferences matching their bachelor/project topic. They write a paper complying with common academic standards, submit it to a mock-up conference, and review submissions of their fellow students. Students also produce a poster and have to defend it in a poster session held publicly on the campus. Engineering Conferences is a course on scientific communication and presentation that also aims at the development of other skills and competences needed in the world of modern engineering. KW - Engineering Conferences Y1 - 2017 CY - Winnipeg ER - TY - CHAP A1 - Neef, Matthias A1 - Fussenecker, Claudia A1 - Niemann, Jörg A1 - Zielke, Thomas ED - Clark, Robin ED - Munkebo Hussmann, Peter ED - Järvinen, Hannu-Matti T1 - Publish your undergraduate research! A mandatory course for master students in engineering T2 - Creativity, innovation and entrepreneurship for engineering education excellence : proceedings of the 46th SEFI Annual Conference 2018, Copenhagen, Denmark N2 - Undergraduate students in engineering often have little exposure to the world of scientific publishing and the culture of sharing research work. While the beneficial exchange between research and teaching is well promoted, while the benefits of conference participation for students have already been surveyed and while courses on scientific writing are readily available, the concept of mini-conferences as part of the curriculum combines all three aspects into one. Therefore, the course "Engineering Conferences" was developed and installed as a mandatory part of a master program for engineering students. The idea is to go beyond simply teaching the standards of academic writing and skills for using scientific publications. By using a learner-centered approach, the students are engaged in typical activities around an active attendance of a real conference. Based on their bachelor thesis, they write a paper complying with common academic standards, submit the paper and review submissions of their fellow students. They also produce a poster and defend their work in a poster session held publicly on campus. This contribution is based on the experience from the first four terms teaching the course. It explains the didactic rationale behind the concept and individual teaching modules, it comprises the collection of useful resources for teaching and organizing scientific publishing and it includes the consequences drawn from course evaluation results. Y1 - 2018 SN - 978-2-87352-016-8 PB - SEFI - Société Européenne pour la Formation des Ingénieurs CY - Brussels ER - TY - JOUR A1 - Feseker, Daniel A1 - Kinell, Mats A1 - Neef, Matthias T1 - Experimental Study on Pressure Losses in Circular Orifices With Inlet Cross Flow JF - Journal of Turbomachinery N2 - The ability to understand and predict the pressure losses of orifices is important in order to improve the air flow within the secondary air system. This experimental study investigates the behavior of the discharge coefficient for circular orifices with inlet cross flow which is a common flow case in gas turbines. Examples of this are at the inlet of a film cooling hole or the feeding of air to a blade through an orifice in a rotor disk. Measurements were conducted for a total number of 38 orifices, covering a wide range of length-to-diameter ratios, including short and long orifices with varying inlet geometries. Up to five different chamfer-to-diameter and radius-to-diameter ratios were tested per orifice length. Furthermore, the static pressure ratio across the orifice was varied between 1.05 and 1.6 for all examined orifices. The results of this comprehensive investigation demonstrate the beneficial influence of rounded inlet geometries and the ability to decrease pressure losses, which is especially true for higher cross flow ratios where the reduction of the pressure loss in comparison to sharp-edged holes can be as high as 54%. With some exceptions, the chamfered orifices show a similar behavior as the rounded ones but with generally lower discharge coefficients. Nevertheless, a chamfered inlet yields lower pressure losses than a sharp-edged inlet. The obtained experimental data were used to develop two correlations for the discharge coefficient as a function of geometrical as well as flow properties. KW - Compressor KW - Gas turbine engines KW - Turbine components KW - Boundary layer development KW - Fluid dynamics KW - Heat transfer KW - Measurement techniques KW - Film cooling KW - Heat transfer phenomena Y1 - 2018 U6 - https://doi.org/10.1115/1.4039842 VL - 140 IS - 7 CY - ASME ER - TY - THES A1 - Neef, Matthias T1 - Analyse des Schlagfluges durch numerische Strömungsberechnung N2 - Mit Hilfe eines Finite-Volumen-Verfahrens wird die dreidimensionale reibungsbehaftete Stroemung um einen schlagenden Fluegel berechnet. Die Bewegungsparamter sind dabei vergleichbar mit den Bedingungen im Reiseflug grosser Voegel. Das numerische Verfahren wird fuer den gezeigten Anwendungsfall, indem eine Methode zur Realisierung von beliebigen periodischen Bewegungen implemetiert wird. Eine Verifizierung erfolgt durch den Vergleich mit analytischen, numerischen und experimentellen Ergebnissen aus der Literatur. Mit dem verifizierten Verfahren werden die instationaeren Groessen wie Druck und Geschwindigkeiten in der Umgebung des bewegten Fluegels berechnet. Daraus ergeben sich ferner die zeitlich gemittelten Groessen wie Schub und Wirkungsgrad des Schlagfluges. Ausserdem wird die Interaktion von Laengs- und Querwirbeln im Nachlauf des schlagenden Fluegels untersucht. Es zeigt sich ein dominanter Einfluss der pulsierenden Randwirbel aufgrund der endlichen Spannweite, waehrend die Anfahr- und Stoppwirbel, verursacht durch die Fluegelbewegung, im Reiseflug grosser Voegel nahezu vernachlaessigbar erscheinen. N2 - The three-dimensional viscous flow around a flapping wing is calculated by means of a finite volume code. The invoked motion parameters are comparable with the conditions in cruising flight of large birds. For the described application the numerical procedure is extended by implementing a method for realisation of arbitrary periodic motions. The verification is obtained by comparison with analytical, numerical and experimental results from existing literature. With the verified method the instationary quantities such as pressure and velocity are known in the vicinity of the wing. This also yields the time averaged values such as thrust and propulsive efficiency of the flapping wing propulsion. Additionally, the interaction between longitudinal and transverse vortices in the wake of the flapping wing is investigated. A dominant influence of the oscillating tip vortices due to the finite span can be seen, while the starting and stopping vortices due to the wing motion appear almost negligible in the cruising flight of large birds. Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:084-14501 UR - http://www.digibib.tu-bs.de/?docid=00001361 VL - ZLR-Forschungsbericht, 2 ER - TY - JOUR A1 - Roedder, Maximilian A1 - Neef, Matthias A1 - Laux, Christoph A1 - Priebe, Klaus-P. T1 - Systematic Fluid Selection for Organic Rankine Cycles and Performance Analysis for a Combined High and Low Temperature Cycle JF - Journal of Engineering for Gas Turbines and Power N2 - The organic Rankine cycle (ORC) is an established thermodynamic process that converts waste heat to electric energy. Due to the wide range of organic working fluids available the fluid selection adds an additional degree-of-freedom to the early design phase of an ORC process. Despite thermodynamic aspects such as the temperature level of the heat source, other technical, economic, and safety aspects have to be considered. For the fluid selection process in this paper, 22 criteria were identified in six main categories while distinguishing between elimination (EC) and tolerance criteria (TC). For an ORC design, the suggested method follows a practical engineering approach and can be used as a structured way to limit the number of interesting working fluids before starting a detailed performance analysis of the most promising candidates. For the first time, the selection process is applied to a two-stage reference cycle, which uses the waste heat of a large reciprocating engine for cogeneration power plants. It consists of a high temperature (HT) and a low temperature (LT) cycle in which the condensation heat of the HT cycle provides the heat input of the LT cycle. After the fluid selection process, the detailed thermodynamic cycle design is carried out with a thermodynamic design tool that also includes a database for organic working fluids. The investigated ORC cycle shows a net thermal efficiency of about 17.4% in the HT cycle with toluene as the working fluid and 6.2% in LT cycle with isobutane as the working fluid. The electric efficiency of the cogeneration plant increases from 40.4% to 46.97% with the both stages of the two-stage ORC in operation. KW - Gas Turbines KW - Cycle Innovations KW - Energy KW - Power systems KW - Fluids Y1 - 2016 U6 - https://doi.org/10.1115/1.4031361 VL - 138 IS - 031701 EP - 3 PB - ASME ER - TY - CHAP A1 - Rödder, Maximilian A1 - Neef, Matthias A1 - Laux, Christoph A1 - Priebe, Klaus-P. T1 - Systematic Fluid Selection for Organic Rankine Cycles (ORC) and Performance Analysis for a Combined High and Low Temperature Cycle T2 - Volume 3: Coal, Biomass and Alternative Fuels; Cycle Innovations; Electric Power; Industrial and Cogeneration N2 - The organic Rankine cycle (ORC) is an established thermodynamic process that converts waste heat to electric energy. Due to the wide range of organic working fluids available the fluid selection adds an additional degree of freedom to the early design phase of an ORC process. Despite thermodynamic aspects such as the temperature level of the heat source, other technical, economic and safety aspects have to be considered. For the fluid selection process in this paper, 22 criteria were identified in six main categories while distinguishing between elimination and tolerance criteria. For an ORC design, the suggested method follows a practical engineering approach and can be used as a structured way to limit the number of interesting working fluids before starting a detailed performance analysis of the most promising candidates. For the first time the selection process is applied to a two-stage reference cycle which uses the waste heat of a large reciprocating engine for cogeneration power plants. It consists of a high temperature and a low temperature cycle in which the condensation heat of the high temperature (HT) cycle provides the heat input of the low temperature (LT) cycle. After the fluid selection process the detailed thermodynamic cycle design is carried out with a thermodynamic design tool that also includes a database for organic working fluids. The investigated ORC cycle shows a net thermal efficiency of about 17,4% in the high temperature cycle with Toluene as the working fluid and 6,2% in low temperature cycle with iso-Butane as the working fluid. The electric efficiency of the cogeneration plant increases from 40,4% to 46,97% with the both stages of the two-stage ORC in operation. Y1 - 2015 UR - https://asmedigitalcollection.asme.org/GT/proceedings/GT2015/56673/Montreal, Quebec, Canada/236733 SN - 978-0-7918-5667-3 U6 - https://doi.org/10.1115/GT2015-42432 PB - American Society of Mechanical Engineers ER - TY - JOUR A1 - Bonk, Christian Dirk A1 - Laux, Christoph A1 - Rödder, Maximilian A1 - Neef, Matthias T1 - Design of a 1 KW Organic Rankine Cycle for Teaching and Research Issues JF - Energy Procedia N2 - This paper deals with the design of a micro-scale ORC plant for teaching and research including the development of an automated control concept. The aim is to provide a safe and environmentally acceptable micro-scale heat engine, which can be developed, implemented and used in university labs for the education of students as well as for small research projects. The test rig allows the support of several learning outcomes on a multi-disciplinary level particularly for the implementation and simulation of small power systems. Special attention was given to the organic working fluid characteristics and its selection process. In addition to the above-mentioned performance goals, favourable safety properties and low global warming potential were decisive in the selection of the novel organic fluid called 3M™ Novec™ 649. The performance and the fluid behaviour of Novec 649 in a micro-scale power cycle are of major interest and the research goal for the test rig presented in this paper. Due to the expected power output of 1 kW, a scroll expander was chosen as the generator drive for the micro plant. In order to design the major parts of the ORC, the thermodynamic simulation software EBSILON®Professional was used. The supply temperature was set to 140 °C. As a result of the simulation, feasible expander inlet pressures spread from 5.5 bar to 8.5 bar. This leads to thermal efficiencies of the ORC in the order of 5 %. Adding a recuperator to the cycle system decreases the operating pressure range but in the end, the thermal efficiency can be increased by 1.5 %-points up to 6.2 %. Finally, an automated control concept is introduced, where the pump is controlled via the fill level measurement system. KW - EBSILON®Professional KW - Micro-Scale ORC Plant KW - Teaching KW - Research KW - Automated Control Concept Y1 - 2017 U6 - https://doi.org/10.1016/j.egypro.2017.09.117 VL - 129 SP - 931 EP - 938 PB - Elsevier ER - TY - CHAP A1 - Helm, Peter A1 - Pugachev, Alexander A1 - Neef, Matthias T1 - Breaking the Swirl With Brush Seals: Numerical Modeling and Experimental Evidence T2 - Proceedings of the ASME Turbo Expo 2008 : presented at the 2008 ASME Turbo Expo, June 9 - 13, 2008, Berlin, Germany N2 - Striving for smaller losses in turbomachinery has led to many advancements in the design of seals. Modern sealing concepts such as brush seals hold a great potential to increase the efficiency of both flight engines and stationary turbines. At the same time, in order to maintain stable operating conditions of the rotor, swirl-induced forces must be kept at a minimum in the sealing channels. Therefore, the influence of the permeable and flexible bristle pack of brush seals on the flow around the rotor surface must be known. In this paper the swirl flow in the cavities of two different seal geometries is studied experimentally and numerically. A conventional three-tooth labyrinth serves as a reference. A second seal arrangement with a bristle pack upstream of two teeth is compared with the reference labyrinth. The swirl is evaluated experimentally from total and static pressure measurements in various axial and circumferential positions. Additionally, the axial swirl distribution is calculated using computational fluid dynamics (CFD). Here, the numerical model of the brush seal is based on the porous medium approach and is calibrated using the experimental values of the leakage and the bristle clearance by adjusting the thickness of the bristle pack. The calibrated CFD model is then used to study the impact of the brush seal on the swirl component of the sealing flow. The observed significant decrease of the swirl by the brush seal shows good agreement with the experimental data. The impact of changes in bristle pack clearance on the swirl is also investigated and compared with experimental evidence. The aim is to show that the brush seals have a natural tendency to interrupt seal swirl. They can therefore be used for swirl control in order to create a beneficial impact on the dynamic stability of turbomachines. Y1 - 2008 SN - 978-0-7918-4314-7 U6 - https://doi.org/10.1115/GT2008-50257 VL - 4 SP - 1387 EP - 1396 PB - ASME CY - New York ER - TY - JOUR A1 - Neef, Matthias A1 - Fritzen, J. P. A1 - Schumacher, G. T1 - Evaluation of mount loads in dynamic testing of a jet engine JF - Mechanical Systems and Signal Processing N2 - In the dynamic testing of jet engines the evaluation of loads on the mount structure is vital for comparison with finite element calculations of such testing. Measuring these loads with the help of strain gauges applied to the structure becomes difficult if the mount is overdetermined and thus not every strain gauge can be assigned to a single load direction. In this study, the overdetermined mount structure of the BR715 engine was examined at one of the three mounting points between the Boeing 717 airframe and the engine, where loads in five directions were reacted. Firstly, the dependence of five measured strains upon known static load conditions at the mounting point had to be determined. For this purpose a static calibration test was carried out where defined forces and moments in known directions were applied to the structure while the output from five strain gauges was measured accordingly. The result was the desired relationship between loads and strains in terms of a matrix, which yields the corresponding load condition of the examined mounting point if multiplied with a set of strains. The same calibration procedure was carried out with a finite element model of the mount, where direct comparison to dynamic load results from the model itself was possible. With this model the validity of the above method was shown as well as possible errors which may occur while evaluating dynamic test results. The method was found to give satisfactory results even for dynamic loading, although some inertia forces disturb the signals in dynamic testing. Finally, the results from an actual dynamic engine test were processed into loads and then compared to the simulated loads from a finite element model of the engine. Good agreement was found and the indication of any remaining discrepancies was used to update the model for an even better representation of the dynamic test loads. Y1 - 2003 UR - http://www.sciencedirect.com/science/article/pii/S0888327001914050 U6 - https://doi.org/10.1006/mssp.2001.1405 VL - 17 IS - 3 SP - 665 EP - 681 PB - Elsevier ER - TY - CHAP A1 - Feseker, Daniel A1 - Kinell, Mats A1 - Neef, Matthias ED - The American Society of Mechanical Engineers, T1 - Experimental Study on Pressure Losses in Circular Orifices With Inlet Cross Flow T2 - Proceedings of the ASME Turbo Expo: Turbine Technical Conference and Exposition - 2017: presented at the ASME Turbo Expo 2017: Turbine Technical Conference and Exposition, June 26-30, 2017 N2 - The ability to understand and predict the pressure losses of orifices is important in order to improve the air flow within the secondary air system. This experimental study investigates the behavior of the discharge coefficient for circular orifices with inlet cross flow which is a common flow case in gas turbines. Examples of this are at the inlet of a film cooling hole or the feeding of air to a blade through an orifice in a rotor disk. Measurements were conducted for a total number of 38 orifices, covering a wide range of length-to-diameter ratios, including short and long orifices with varying inlet geometries. Up to five different chamfer-to-diameter and radius-to-diameter ratios were tested per orifice length. Furthermore, the static pressure ratio across the orifice was varied between 1.05 and 1.6 for all examined orifices. The results of this comprehensive investigation demonstrate the beneficial influence of rounded inlet geometries and the ability to decrease pressure losses, which is especially true for higher cross flow ratios where the reduction of the pressure loss in comparison to sharp-edged holes can be as high as 54%. With some exceptions, the chamfered orifices show a similar behavior as the rounded ones but with generally lower discharge coefficients. Nevertheless, a chamfered inlet yields lower pressure losses than a sharp-edged inlet. The obtained experimental data were used to develop two correlations for the discharge coefficient as a function of geometrical as well as flow properties. Y1 - 2017 UR - https://asmedigitalcollection.asme.org/GT/proceedings/GT2017/50886/Charlotte, North Carolina, USA/241903 SN - 978-0-7918-5088-6 U6 - https://doi.org/10.1115/GT2017-64143 PB - The American Society of Mechanical Engineers CY - New York ER - TY - CHAP A1 - Laux, Christoph A1 - Gotter, Andreas A1 - Neef, Matthias T1 - Experimental investigation of a low pressure steam Rankine cycle for waste heat utilization of internal combustion engines T2 - Proceedings of the 5th International Seminar on ORC Power Systems N2 - High heat losses via exhaust gas and coolant in internal combustion engines (ICE) are the basis for numerous investigations regarding downstream processes for power generation. The most promising concepts are Organic Rankine Cycles (ORC) and Steam Rankine Cycles (SRC). In previous work of the Center of Innovative Energy Systems, Düsseldorf (Germany), the technical and economic feasibility of a low pressure SRC has been investigated and the advantages in comparison to organic Rankine cycles are highlighted. A distinctive feature of the cycle is the use of the ICE coolant heat for evaporation, which limits the cycles maximum steam pressure to values below atmospheric pressure. This work presents first results of a test rig with data reconciliation according to DIN 2048 to validate the simulation results and design calculations. As a basis for the experimental investigations, a gas fired CHP plant was selected. The design of the test rig is optimized for the operation in the laboratory, where the coolant heat is emulated by a tempering device and the exhaust heat of the CHP plant is emulated by a gas burner. With the designed test rig, it is possible to control the volume flow and the temperatures of the coolant and exhaust gas, so that different load conditions of the gas fired CHP plant can be investigated. For initial tests, the turbine in the SRC is replaced by a throttle to achieve the pressure drop of the turbine. The experimental results show, that the exhaust and coolant heat of a 36 kWel CHP plant can be emulated and the performance expectations of the cycle can be met in stable steady-state conditions. Based on the measurement results and the turbine design calculations an electric power output of the cycle of 3.8 kW will be possible, which results in a cycle efficiency of about 6.5 % and an increase of the electrical power output of the CHP plant of about 10 %. The results show that the plant concept is technically feasible and, with further optimization, also represents an alternative to ORC plants in terms of increasing the efficiency of a cogeneration plant. Y1 - 2019 SN - 978-90-9032038-0 PB - The National Technical University of Athens (NTUA) CY - Athens ER - TY - CHAP A1 - Laux, Christoph A1 - Goebel, Johannes A1 - Neef, Matthias A1 - Gotter, Andreas T1 - Investigation in the Technical and Economic Feasibility of a Low-Pressure Steam Cycle for the Waste Heat Utilization of a Cogeneration Plant T2 - Proceedings of the ASME Turbo Expo: Turbine Technical Conference and Exposition - 2015 : presented at the ASME 2015 Turbo Expo: Turbine Technical Conference and Exposition, June 15 - 19, 2015, Montreal, Quebec, Canada / sponsored by the International Gas Turbine Institute N2 - This paper deals with the investigation in the technical and economic feasibility of a low-pressure steam cycle for the waste heat utilization of a combined heat and power (CHP) plant. The proposed steam cycle uses a pressure level below atmospheric pressure which allows to use the heat from the motor’s coolant for evaporation. The cycle is designed to increase the maximum electrical efficiency of a gas fired reciprocating engine and to increase operational flexibility for varying heat demand. Since organic Rankine cycle (ORC) plants are already being successfully used for waste heat recovery, advantages of the low-pressure steam Rankine cycle (SRC) over an ORC are highlighted. Many ORC fluids are toxic or flammable and thus have an increased risk potential compared to water. An additional advantage of water compared to ORC fluids is the possibility of superheating above 500 °C. The technical feasibility of the proposed cycle is studied by the detailed design of the individual system components such as turbine, heat exchangers and auxiliary parts. This includes the detailed thermodynamic design of the full cycle for the calculation of plant efficiencies. As a basis for future experimental investigations, a cogeneration plant with an electrical output of 50 kWel was selected as a heat source for the steam cycle. The design geometries of the turbine and the heat exchanger are presented along with efficiency and cost predictions. A subsonic radial turbine with a rotational speed of 155,000 rpm was selected. The maximum turbine output is about 7.5 kW. The use of a flash evaporator is investigated to reduce the size and the costs for the evaporator. The suggested steam cycle helps to increase the electrical efficiency of the CHP plant by 4.5% points from an original 36.5% to 41.0%. The steam cycle itself has an electrical efficiency of approximately 9%. Additionally, the condensation temperature in this steam cycle is high enough to be extracted as useful heat output to generate domestic water with a temperature of 50°C. Y1 - 2015 SN - 978-0-7918-5667-3 VL - 3: Coal, biomass and alternative fuels - cycle innovations - electric power - industrial and cogeneration PB - International Gas Turbine Institute (ASME) CY - New York ER -