665 research outputs found

    Proceedings of SIRM 2023 - The 15th European Conference on Rotordynamics

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    It was our great honor and pleasure to host the SIRM Conference after 2003 and 2011 for the third time in Darmstadt. Rotordynamics covers a huge variety of different applications and challenges which are all in the scope of this conference. The conference was opened with a keynote lecture given by Rainer Nordmann, one of the three founders of SIRM “Schwingungen in rotierenden Maschinen”. In total 53 papers passed our strict review process and were presented. This impressively shows that rotordynamics is relevant as ever. These contributions cover a very wide spectrum of session topics: fluid bearings and seals; air foil bearings; magnetic bearings; rotor blade interaction; rotor fluid interactions; unbalance and balancing; vibrations in turbomachines; vibration control; instability; electrical machines; monitoring, identification and diagnosis; advanced numerical tools and nonlinearities as well as general rotordynamics. The international character of the conference has been significantly enhanced by the Scientific Board since the 14th SIRM resulting on one hand in an expanded Scientific Committee which meanwhile consists of 31 members from 13 different European countries and on the other hand in the new name “European Conference on Rotordynamics”. This new international profile has also been emphasized by participants of the 15th SIRM coming from 17 different countries out of three continents. We experienced a vital discussion and dialogue between industry and academia at the conference where roughly one third of the papers were presented by industry and two thirds by academia being an excellent basis to follow a bidirectional transfer what we call xchange at Technical University of Darmstadt. At this point we also want to give our special thanks to the eleven industry sponsors for their great support of the conference. On behalf of the Darmstadt Local Committee I welcome you to read the papers of the 15th SIRM giving you further insight into the topics and presentations

    Vedelkütustest moodustatud küttesegu töötlemise süsteem sädesüütega mootorgeneraatorites kasutamiseks kriisi olukorras

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    A Thesis for applying for the degree of Doctor of Philosophy in Engineering Sciences.Väitekiri filosoofiadoktori kraadi taotlemiseks tehnikateaduse erialal.In times of crisis and war, there is a high probability that the operation of electrical networks will be disrupted, and therefore some distribution networks may remain without electricity. As a result, important information- and communication technology nodes of the core networks of the country's critical infrastructure are also without electricity. In a crisis situation, the missing electrical energy can be produced with widespread spark ignition engine-generators, but in their case, flexibility in the use of fuels is important. In a crisis situation, all possible engine fuels, both light and heavy, must be used. The problem with the use of engine-generators for the production of electricity is their single-fuel nature. By heating the fuel mixture, better evaporation is achieved and thus it is possible to bypass the problem and use all liquid fuels intended for internal combustion engines to produce electricity in a spark-ignition engine-generator. The dissertation is based on six articles. The research paper described the effects of EU and NATO legislative acts on the liquid fuels used in Estonia, analyzed solutions for solving problems related to energy security in Estonia, analyzed the bottlenecks in the use of diesel and biodiesel fuels in compression ignition engines, developed a technical solution for a air-fuel mixture processing system made from different fuels, and improved the solution so that it is suitable for use with spark ignition engine and engine experiments were performed. The aim of the work was to develop a air-fuel mixture processing system made of different liquid fuels for a spark-ignition engine, and its suitability in practice was assessed. The aim of the system is to adapt the air-fuel mixture for use in a spark-ignition engine in order to ensure the production of distributed electricity in times of crisis and war to support the country's critical infrastructure. The conducted research and the developed solution contribute to the production of distributed electricity with spark ignition engine-generator in a crisis or war situation, using currently available liquid fuel to supply the country's information systems with electricity until NATO Article 5 is triggered, if necessary.Kriisi- ja sõjaajal on suure tõenäosusega elektrivõrkude töö häiritud ja seetõttu võivad osad jaotusvõrgud jääda elektrita. Elektrita on sellest tulenevalt ka riigi kriitilise informatsiooni- ja kommunikatsiooni tehnoloogia infrastruktuuri tuumvõrkude olulised sõlmed. Kriisisituatsioonis saab puuduvat elektrienergiat toota laialtlevinud sädesüütega mootor-generaatoritega kuid nende puhul on oluline kütuste kasutamise paindlikkus. Kriisiolukorras tuleb kasutada kõiki võimalikke mootorikütuseid, nii kerge- kui raskekütuseid. Mootor-generaatorite kasutamisel elektrienergia tootmiseks on probleemiks nende ühekütuselisus. Küttesegu kuumutamisega saadakse parem aurustumine ja nii on võimalik mööduda probleemist ning kasutada sädesüütega mootor-generaatoris elektrienergia tootmiseks kõiki sisepõlemismootorile ettenähtud vedelkütuseid. Väitekiri on koostatud kuue artikli põhjal. Uurimustöös kirjeldati EL ja NATO seadusandlike aktide mõjud Eestis kasutatavatele vedelkütustele, analüüsiti lahendusi energiajulgeolekuga seotud probleemide lahendamisele Eestis, analüüsiti diisli- ja biodiislikütuste kasutamise kitsaskohti survesüütega mootorites, töötati välja erinevatest kütustest valmistatud küttesegu töötlemise süsteemi tehniline lahendus, lahendust täiendati nii, et see sobiks kasutamiseks sädesüütega mootoril ning teostati mootorikatsetused. Töö eesmärgiks oli töötada välja erinevatest vedelkütustest moodustatud küttesegu töötlemise süsteem sädesüütega mootorile ja hinnati selle sobivust praktikas. Süsteemi eesmärgiks on kohandada küttesegu sädesüütega mootoris kasutamiseks, et tagada kriisi- ja sõjaajal hajuseleketrienergia tootmine riigi kriitilise infrastruktuuri toetamiseks. Läbiviidud uuringud ja väljatöötatud lahendus aitavad kaasa kriisi- või sõjaolukorras sädesüütega mootor-generaatoriga hajutatud elektrienergia tootmisele, kasutades selleks hetkel kättesaadavat vedelkütust, et varustada elektriga riigi IKT süsteeme kuniks vajadusel käivitub NATO artikkel 5.Publication of this thesis is supported by Estonian University of Life Sciences and the Doctoral School of Energy and Geotechnology III and Estonian University of Life Sciences ASTRA project „Value-chain based bio-economy

    Control and estimation techniques applied to smart microgrids : a review

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    DATA AVAILABILITY : No data was used for the research described in the article.The performance of microgrid operation requires hierarchical control and estimation schemes that coordinate and monitor the system dynamics within the expected manipulated and control variables. Smart grid technologies possess innovative tools and frameworks to model the dynamic behaviour of microgrids regardless of their types, structures, etc. Various control and estimation technologies are reviewed for developing dynamic models of smart microgrids. The hierarchical system of a microgrid control consists of three architectural layers, primary, secondary and tertiary, which need to be supported by real-time monitoring and measurement environment of the system variables and parameters. Various control and estimation schemes have been devised to handle the dynamic performance of microgrids in the function of control layers requirement. Firstly, control schemes in the innovative grid environment are evaluated to understand the dynamics of the developed technologies. Six control technologies, linear, non-linear, robust, predictive, intelligent and adaptive, are mainly used to model the control design within the layer(s) regardless of the types of microgrids. Secondly, the estimation technologies are evaluated based on the state of variables, locations and modelling of microgrids that can efficiently support the performance of the controllers and operating microgrids. Finally, a future vision for designing hierarchical and architectural control techniques for the optimal operation of intelligent microgrids is also provided. Therefore, this study will serve as a fundamental conceptual framework to select a perfect optimal design modelling strategy and policy-making decisions to control, monitor and protect the innovative electrical network.http://www.elsevier.com/locate/rserhj2023Electrical, Electronic and Computer Engineerin

    Integration of Flywheel Energy Storage Systems in Low Voltage Distribution Grids

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    A Flywheel Energy Storage System (FESS) can rapidly inject or absorb high amounts of active power in order to support the grid, following abrupt changes in the generation or in the demand, with no concern over its lifetime. The work presented in this book studies the grid integration of a high-speed FESS in low voltage distribution grids from several perspectives, including optimal allocation, sizing, modeling, real-time simulation, and Power Hardware-in-the-Loop testing

    Multi-body dynamics in vehicle engineering

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    Since Euler's original gyro-dynamic analysis nearly two and a half centuries ago, the use of multi-body dynamics (MBD) has spread widely in application scope from large displacement rigid body dynamics to infinitesimal amplitude elastodynamics. In some cases, MBD has become a multi-physics multi-scale analysis, comprising contact mechanics, tribo-dynamics, terramechanics, thermodynamics, biomechanics, etc. It is an essential part of all analyses in many engineering disciplines, including vehicle engineering. This paper provides an overview of historical developments with emphasis on vehicle development and investigation of observed phenomena, including noise, vibration and harshness. The approach undertaken is comprehensive and provides a uniquely focused perspective, one which has not hitherto been reported in the literature

    Modular power electronics integration for improved performance in C-GEN generation systems

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    ‘C-GEN’ machines derive the name from the rotor, which consists of steel ‘C’ core modules, which are built around a highly modular design and specifically designed for renewable energy generation. The C-GEN machine can be easily scaled in power, dismantled in parts for maintenance, and even carry on operation with defective modules. Such high degree of modularity on the machine side has yet to be matched with modular power electronics conversion and control on the electrical side. In this thesis, the modular power electronics topology is integrated in the C-GEN machine, which aims to improve the performance of the generation system in a wide range of rotational speed, especially at partial load operation. According to the mechanical structure and electrical specification of a 16kW C-GEN machine, simulation models which include the C-GEN machine model and modular power electronics model are built. On the basis of the C-GEN machine model, four modular power electronics options are proposed, and these options are mainly assessed in terms of power losses in rectifiers and fault tolerance. A novel circuit named ‘electric gear’ is proposed to adjust the modulation index of the rectifiers in the low speed region. The electric gear is able to transmit the rectifiers’ connection between parallel and series quickly, thus the DC voltage seen by the rectifier is changed, and the modulation index of the rectifier is therefore varied. Utilising the outcomes from the studies above, the modular power electronics technology is applied in a practical wave generation project. The simulation results of this project indicate that this modular power electronics topology can maintain the modulation index larger than 0.5 as long as the generator runs more than 15% of its rated speed and reduce the power loss in rectifiers by up to 70%. As a benefit brought by the improvement of the modulation index, the power quality is enhanced as well: the current THD is less than 5% in a wide rotational speed range of the generator. Finally, the functionality and operation of the modular power electronics technology and electric gear are demonstrated in the realistic system via the hardware experiment

    Komponentenbasierte dynamische Modellierung von Energiesystemen und Energiemanagement-Strategien für ein intelligentes Stromnetz im Heimbereich

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    The motivation of this work is to present an energy cost reduction concept in a home area power network (HAPN) with intelligent generation and flexible load demands. This study endeavors to address the energy management system (EMS) and layout-design challenges faced by HAPN through a systematic design approach. The growing demand for electricity has become a significant burden on traditional power networks, prompting power engineers to seek ways to improve their efficiency. One such solution is to integrate dispersed generation sources, such as photovoltaic (PV) and storage systems, with an appropriate control mechanism at the distribution level. In recent years, there has been a significant increase in interest in the installation of PV-Battery systems, due to their potential to reduce carbon emissions and lower energy costs. This research proposes an optimal economic power dispatch strategy using Model Predictive Control (MPC) to enhance the overall performance of HAPN. A hybrid AC/DC microgrid concept is proposed to address the control choices made by the appliance scheduling and hybrid switching approaches based on a linear programming optimization framework. The suggested optimization criteria improve consumer satisfaction, minimize grid disconnections, and lower overall energy costs by deploying inexpensive clean energy generation and control. Various examples from actual case study demonstrate the use of the established EMS and design methodology.Die Motivation dieser Arbeit besteht darin, ein Konzept zur Senkung der Energiekosten in einem Heimnetzwerk (HAPN) mit intelligenter Erzeugung und exiblen Lastanforderungen vorzustellen. Im Rahmen dieser Forschungsarbeit wird ein Entwurf für ein HAPN entwickelt, indem das Energiemanagementsystem (EMS) und der Entwurf des Layouts auf der Grundlage des Systemmodells und der betrieblichen Anforderungen gelöst werden. Die steigende Nachfrage nach Elektrizität ist für traditionelle Stromnetze kostspielig und infrastrukturintensiv. Daher konzentrieren sich Energietechniker darauf, die Effizienz der derzeitigen Netze zu erhöhen. Dies kann durch die Integration verteilter Erzeugungsanlagen (z. B. Photovoltaik (PV), Speicher) mit einem geeigneten Kontrollmechanismus für das Energiemanagement auf der Verteilungsseite erreicht werden. Darüber hinaus hat das Interesse an der Installation von PV-Batterie-basierten Systemen aufgrund der Reduzierung der CO2-Emissionen und der Senkung der Energiekosten erheblich zugenommen. Es wird eine optimale wirtschaftliche Strategie für den Energieeinsatz unter Verwendung einer modellprädiktiven Steuerung (MPC) entwickelt. Es wird zudem ein hybrides AC/DC-Microgrid-Konzept vorgeschlagen, um die Steuerungsentscheidungen, die von den Ansätzen der Geräteplanung und der hybriden Umschaltung getroffen werden, auf der Grundlage eines linearen Programmierungsoptimierungsrahmens zu berücksichtigen. Die vorgeschlagenen Optimierungskriterien verbessern die Zufriedenheit der Verbraucher, minimieren Netzabschaltungen und senken die Gesamtenergiekosten durch den Einsatz von kostengünstiger und sauberer Energieerzeugung. Verschiedene Beispiele aus einer Fallstudie demonstrieren den Einsatz des entwickelten EMS und der Entwurfsmethodik

    Proceedings of the 2nd Energy Security and Chemical Engineering Congress

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    Mechanical engineering is a field that is continuously evolving as a profession to provide sustainable design, products and technologies for society. Mechanical engineering products, in conjunction with technological advances in other sectors, contribute to noise, water and air pollution, and the degradation of land and landscape. The rate of production, both energy and products, is increasing at such a rapid rate that natural regeneration can no longer sustain. Emission control is a fast-growing topic for mechanical engineers and others, encompassing the development of machines and processes that produce fewer pollutants as well as new materials and processes that can decrease or eliminate pollution that has already been generated. And, in an increasingly environmentally conscious world, the concept of sustainability is also intrinsically important to the success or failure of any engineering product or processes. Mechanical engineers thus play a central role in applying a truly modern approach for enabling the global transition to green energy and sustainable prac-tices. To address climate change, researchers are progressively looking into a wide range of novel solutions for energy conversion, engine efficiency, alternative fuels, nature-inspired materials, enhanced manufacturing processes and so on. In this context, this book presents part of the proceedings of the Mechanical and Materials track of the 2nd Energy Security and Chemical Engineering Congress (ESChE 2021) as presented by the academics, researchers and postgraduate students. The book provides insights into different aspects of mechanical processes, nanoma-terials and alternate fuels that set the stage for development of sustainable techno-logical solutions. The content of this book will be useful for students, researchers and professionals working in the areas of mechanical engineering, materials, energy technologies, optimization and allied fields

    Power Electronics Applications in Renewable Energy Systems

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    The renewable generation system is currently experiencing rapid growth in various power grids. The stability and dynamic response issues of power grids are receiving attention due to the increase in power electronics-based renewable energy. The main focus of this Special Issue is to provide solutions for power system planning and operation. Power electronics-based devices can offer new ancillary services to several industrial sectors. In order to fully include the capability of power conversion systems in the network integration of renewable generators, several studies should be carried out, including detailed studies of switching circuits, and comprehensive operating strategies for numerous devices, consisting of large-scale renewable generation clusters
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