TY - JOUR A1 - Alebouyeh Samami, Behzad A1 - Pieper, Martin A1 - Breitbach, Gerd A1 - Hodapp, Josef T1 - Heat production in the windings of the stators of electric machines under stationary condition JF - Heat and mass transfer N2 - In electric machines due to high currents and resistive losses (joule heating) heat is produced. To avoid damages by overheating the design of effective cooling systems is required. Therefore the knowledge of heat sources and heat transfer processes is necessary. The purpose of this paper is to illustrate a good and effective calculation method for the temperature analysis based on homogenization techniques. These methods have been applied for the stator windings in a slot of an electric machine consisting of copper wires and resin. The key quantity here is an effective thermal conductivity, which characterizes the heterogeneous wire resin-arrangement inside the stator slot. To illustrate the applicability of the method, the analysis of a simplified, homogenized model is compared with the detailed analysis of temperature behavior inside a slot of an electric machine according to the heat generation. We considered here only the stationary situation. The achieved numerical results are accurate and show that the applied homogenization technique works in practice. Finally the results of simulations for the two cases, the original model of the slot and the homogenized model chosen for the slot (unit cell), are compared to experimental results. Y1 - 2014 U6 - http://dx.doi.org/10.1007/s00231-014-1371-8 SN - 0947-7411 (Print) ; 1432-1181 (E-Journal) VL - 50 SP - 1707 EP - 1716 PB - Springer CY - Heidelberg ER - TY - CHAP A1 - Pieper, Martin A1 - Schulz, Silvia T1 - Teaching Simulation Methods with COMSOL Multiphysics N2 - This paper describes two courses on simulation methods for graduate students: “Simulation Methods” and “Simulation and Optimization in Virtual Engineering” The courses were planned to teach young engineers how to work with simulation software as well as to understand the necessary mathematical background. As simulation software COMSOL is used. The main philosophy was to combine theory and praxis in a way that motivates the students. In addition “soft skills” should be improved. This was achieved by project work as final examination. As underlying didactical principle the ideas of Bloom’s revised taxonomy were followed. The paper basically focusses on educational aspects, e.g. how to structure the course, plan the exercises, organize the project work and include practical COMSOL examples. KW - COMSOL Multiphysics KW - Optimization module KW - LiveLink for MATLAB KW - Bloom Taxonomy KW - education Y1 - 2014 ER - TY - CHAP A1 - Wetter, Martin A1 - Kern, Alexander T1 - Number of lightning strikes to tall structures - comparison of calculations and measurements using a modern lightning monitoring system T2 - 2014 International Conference on Lightning Protection (ICLP), Shanghai, China Y1 - 2014 SP - 1 EP - 7 ER - TY - JOUR A1 - Srivastava, A. A1 - Lahiri, S. A1 - Maiti, M. A1 - Knolle, F. A1 - Hoyler, Friedrich A1 - Scherer, Ulrich W. A1 - Schnug, E. W. T1 - Study of naturally occurring radioactive material (NORM) in top soil of Punjab State from the North Western part of India JF - Journal of Radioanalytical and Nuclear Chemistry Y1 - 2014 U6 - http://dx.doi.org/0.1007/s10967-014-3450-1 SN - 1588-2780 (E-Journal); 0022-4081 (Print); 0134-0719 (Print); 0236-5731 (Print); 1417-2097 (Print) VL - 2014 IS - 302 SP - 1049 EP - 1052 PB - Springer Nature CY - Basel ER - TY - THES A1 - Reyes Ochoa, Leonel T1 - Engineering aspects of a parabolic trough collector field with direct steam generation and an organic rankine cycle Y1 - 2014 N1 - Aachen, Fachhochsch., Masterarbeit, 2014 PB - Fachhochschule Aachen CY - Aachen ER - TY - CHAP A1 - Rousseau, Alain A1 - Kern, Alexander T1 - How to deal with environmental risk in IEC 62305-2 T2 - 2014 International Conference on Lightning Protection (ICLP), Shanghai, China N2 - The 2nd edition of the lightning risk management standard (IEC 62305-2) considers structures, which may endanger environment. In these cases, the loss is not limited to the structure itself, which is valid for usual structures. In the past (Edition 1) this danger was simply taken into account by a special hazard factor, multiplying the existing risk for the structure with a number. Now, in the edition 2, we add to the risk for the structure itself a “second risk” due to the losses outside the structure. The losses outside can be treated independently from what occurs inside. This is a major advantage to analyze the risk for sensitive structures, like chemical plants, nuclear plants, or structures containing explosives, etc. In this paper, the existing procedure given by the European version EN 62305-2 Ed.2 is further developed and applied to a few structures. Y1 - 2014 SP - 521 EP - 527 ER - TY - CHAP A1 - Kern, Alexander A1 - Braun, Christian T1 - Risk management according to IEC 62305-2 edition 2: 2010–12 assessment of structures with a risk of explosion T2 - 2014 International Conference on Lightning Protection (ICLP), Shanghai, China N2 - Risk management for structures with a risk of explosion should be considered very carefully when performing a risk analysis according to IEC 62305-2. In contrast to the 2006 edition of the standard, the 2010 edition describes the topic “Structures with a risk of explosion” in more detail. Moreover, in Germany separate procedures and parameters are defined for the risk analysis of structures with a risk of explosion (Supplement 3 of the German DIN EN 62305-2 standard). This paper describes the contents and the relevant calculations of this Supplement 3, together with a numerical example. Y1 - 2014 SP - 1237 EP - 1242 ER - TY - JOUR A1 - Vogt, C. A1 - Mottaghy, Darius A1 - Rath, V. A1 - Marquart, G. A1 - Dijkshoorn, L. A1 - Wolf, A. A1 - Clauser, C. T1 - Vertical variation in heat flow on the Kola Peninsula: palaeoclimate or fluid flow? JF - Geophysical Journal International N2 - Following earlier studies, we present forward and inverse simulations of heat and fluid transport of the upper crust using a local 3-D model of the Kola area. We provide best estimates for palaeotemperatures and permeabilities, their errors and their dependencies. Our results allow discriminating between the two mentioned processes to a certain extent, partly resolving the non-uniqueness of the problem. We find clear indications for a significant contribution of advective heat transport, which, in turn, imply only slightly lower ground surface temperatures during the last glacial maximum relative to the present value. These findings are consistent with the general background knowledge of (i) the fracture zones and the corresponding fluid movements in the bedrock and (ii) the glacial history of the Kola area. Y1 - 2014 U6 - http://dx.doi.org/10.1093/gji/ggu282 SN - 1365-246X VL - 199 IS - 2 SP - 829 EP - 843 PB - Oxford University Press CY - Oxford ER - TY - CHAP A1 - Altay, Okyay A1 - Taddei, Francesca A1 - Butenweg, Christoph A1 - Klinkel, Sven T1 - Vibration mitigation of wind turbine towers with tuned mass dampers T2 - Wind turbine control and monitoring. (Advances in industrial control) N2 - Because of its minor environmental impact, electricity generation using wind power is getting remarkable. The further growth of the wind industry depends on technological solutions to the challenges in production and construction of the turbines. Wind turbine tower vibrations, which limit power generation efficiency and cause fatigue problems with high maintenance costs, count as one of the main structural difficulties in the wind energy sector. To mitigate tower vibrations auxiliary measures are necessary. The effectiveness of tuned mass damper is verified by means of a numeric study on a 5 MW onshore reference wind turbine. Hereby, also seismic-induced vibrations and soil–structure interaction are considered. Acquired results show that tuned mass damper can effectively reduce resonant tower vibrations and improve the fatigue life of wind turbines. This chapter is also concerned with tuned liquid column damper and a semiactive application of it. Due to its geometric versatility and low prime costs, tuned liquid column dampers are a good alternative to other damping measures, in particular for slender structures like wind turbines. Y1 - 2014 SN - 978-3-319-08412-1 (Print) ; 978-3-319-08413-8 (E-Book) U6 - http://dx.doi.org/10.1007/978-3-319-08413-8_12 SP - 337 EP - 373 PB - Springer CY - Cham ; Heidelberg ; New York ; Dordrecht ; London ER - TY - BOOK A1 - Klinkel, Sven A1 - Butenweg, Christoph A1 - Lin, Gao A1 - Holtschoppen, Britta T1 - Seismic design of industrial facilities : Proceedings of the International Conference on Seismic Design of Industrial Facilities (SeDIF) / Sven Klinkel, Christoph Butenweg, Gao Lin, Britta Holtschoppen Editors Y1 - 2014 SN - 978-3-658-02809-1 (Print) ; 978-365-80281-0-7 (E-Book) U6 - http://dx.doi.org/10.1007/978-3-658-02810-7 PB - Springer Vieweg CY - Wiesbaden ER -