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In: Alfha.net / Sektion Bauingenieurwesen: 1. [Erster] Erfahrungsaustausch : Absolventen des Fachbereichs Bauingenieurwesens berichten. 13. Oktober 2006. S. 16-17 Der Umbau des Aachener Buschtunnels im Rahmen des europäischen Hochgeschwindigkeitsschienennetzes wird im sogenannten "Neuen Österreichischen Tunnelbauverfahren (NOeT)", also ein Ausbau in Kalotte, Strosse und Sohle durchgeführt.
An array of 50 MHz quartz microbalances (QMBs) coated with a dendronized polymer was used to detect small amounts of volatile organic compounds (VOCs) in the gas phase. The results were compared to those obtained with the commonly used 10 MHz QMBs. The 50 MHz QMBs proved to be a powerful tool for the detection of VOCs in the gas phase; therefore, they represent a promising alternative to the much more delicate surface acoustic wave devices (SAWs).
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
In addition to very high safety and reliability requirements, the design of internal combustion engines (ICE) in aviation focuses on economic efficiency. The objective must be to design the aircraft powertrain optimized for a specific flight mission with respect to fuel consumption and specific engine power. Against this background, expert tools provide valuable decision-making assistance for the customer. In this paper, a mathematical calculation model for the fuel consumption of aircraft ICE is presented. This model enables the derivation of fuel consumption maps for different engine configurations. Depending on the flight conditions and based on these maps, the current and the integrated fuel consumption for freely definable flight emissions is calculated. For that purpose, an interpolation method is used, that has been optimized for accuracy and calculation time. The mission boundary conditions flight altitude and power requirement of the ICE form the basis for this calculation. The mathematical fuel consumption model is embedded in a parent program. This parent program presents the simulated fuel consumption by means of an example flight mission for a representative airplane. The focus of the work is therefore on reproducing exact consumption data for flight operations. By use of the empirical approaches according to Gagg-Farrar [1] the power and fuel consumption as a function of the flight altitude are determined. To substantiate this approaches, a 1-D ICE model based on the multi-physical simulation tool GT-Suite® has been created. This 1-D engine model offers the possibility to analyze the filling and gas change processes, the internal combustion as well as heat and friction losses for an ICE under altitude environmental conditions. Performance measurements on a dynamometer at sea level for a naturally aspirated ICE with a displacement of 1211 ccm used in an aviation aircraft has been done to validate the 1-D ICE model. To check the plausibility of the empirical approaches with respect to the fuel consumption and performance adjustment for the flight altitude an analysis of the ICE efficiency chain of the 1-D engine model is done. In addition, a comparison of literature and manufacturer data with the simulation results is presented.
Ein von der Arbeitsgemeinschaft (AG) Solar NRW und diversen Industriepartnern gefördertes und an der Fachhochschule Aachen, Abt. Jülich durchgeführtes Forschungsprojekt „Blitzschutz für netz-autarke Hybridanlagen“ machte es möglich, sich mit dem Blitzschutz speziell solcher Anlagen näher zu beschäftigen. Vermehrt bekannt gewordene Schadensfälle an nicht netz-gekoppelten Hybridanlagen waren der Auslöser, den Schutz zu überdenken. Definiertes Ziel war es, für netz-autarke energietechnische Anlagen ein Konzept zum Schutz vor Blitzeinwirkungen zu erstellen. Diese Anlagen bestehen üblicherweise aus einer oder mehreren Photovoltaikanlagen, ggf. auch Solarthermieanlagen und einem oder mehreren kleineren Windgeneratoren (sie werden deshalb auch als Hybridanlagen bezeichnet). Zur Erhöhung der Versorgungssicherheit kann noch ein Dieselaggregat dazukommen. Hybridanlagen werden vor allem in Gebieten mit sehr schlechter öffentlicher Energieversorgung eingesetzt, d.h. insbesondere in relativ dünn bewohnten Gebieten und in Entwicklungsländern. Dem Blitzschutz von Hybridanlagen kommt dabei eine steigende Bedeutung zu. Besonderes Augenmerk in dem genannten Forschungsprojekt sollte dabei auf die technisch/wirtschaftliche Ausgewogenheit des Schutzes gelegt werden: • die Schutzmaßnahmen sollen nur in solchen Fällen eingesetzt werden, wo dies als Ergebnis von Risikoanalysen sinnvoll erscheint; • für typische netz-autarke Hybridanlagen sollen die Schutzmaßnahmen ohne deutliche Verteuerung realisierbar sein (es soll also kein absoluter Schutz realisiert werden; ggf. soll lediglich der auftretende Schaden soweit möglich minimiert werden). Dazu wurde in einem ersten Schritt zunächst eine Aufnahme des Iststandes einiger typischer netz-autarker Hybridanlagen und deren einzelnen Komponenten durchgeführt. Aufgrund dessen wurde eine umfassende Risikoanalyse zur Blitzbedrohung dieser Anlagen auf der Basis von VDE V 0185 Teil 2:2002-11 [1] erstellt. Die Ergebnisse mündeten in ein technisch/wirtschaftlich ausgewogenes Konzept für den Anlagen- Blitzschutz (d.h. insbesondere dem Schutz vor direkten Blitzeinschlägen und deren unmittelbaren Auswirkungen) nach VDE V 0185 Teil 3:2002-11 [2] und für den Elektronik-Blitzschutz (d.h. für den Schutz vor Überspannungen durch direkte, insbesondere aber auch indirekte Blitzeinschläge) nach VDE V 0185 Teil 4:2002-11 [3]. Aufgrund der gesammelten Ergebnisse konnten dabei allgemeine Empfehlungen für den Äußeren und Inneren Blitzschutz von regenerativen Energieerzeugungssystemen erstellt werden. Diese sollen in Schulungen einmünden, die für Hersteller und Betreiber von Hybridanlagen angeboten werden. Durch die Anwendung wird der Schutz der Anlagen vor Blitzeinwirkung und elektromagnetischen Störungen verbessert, was sich in einer reduzierten Ausfallwahrscheinlichkeit bzw. erhöhten Verfügbarkeit wiederspiegelt. An einigen ausgewählten Anlagen werden mit Hilfe der im Projekt involvierten Industriepartner die Schutzmaßnahmen realisiert. Hierbei entstanden den Eigentümern bzw. Betreibern der Anlagen keine Kosten. In diesem Beitrag werden beispielhaft drei Anlagenprojekte detailliert gezeigt. Es handelt sich dabei um eine Schweinezuchtfarm in Magallón (Spanien, Zaragozza), das bioklimatische Haus (Kreta, Heraklion) und die Tegernseer- Hütte (Deutschland, Lenggries).
In energy economy forecasts of different time series are rudimentary. In this study, a prediction for the German day-ahead spot market is created with Apache Spark and R. It is just an example for many different applications in virtual power plant environments. Other examples of use as intraday price processes, load processes of machines or electric vehicles, real time energy loads of photovoltaic systems and many more time series need to be analysed and predicted.
This work gives a short introduction into the project where this study is settled. It describes the time series methods that are used in energy industry for forecasts shortly. As programming technique Apache Spark, which is a strong cluster computing technology, is utilised. Today, single time series can be predicted. The focus of this work is on developing a method to parallel forecasting, to process multiple time series simultaneously with R and Apache Spark.
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.
Experimental and numerical investigation on the effect of pressure on micromix hydrogen combustion
(2021)
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.
Investigation Of The Seismic Behaviour Of Infill Masonry Using Numerical Modelling Approaches
(2017)
Masonry is a widely spread construction type which is used all over the world for different types of structures. Due to its simple and cheap construction, it is used as non-structural as well as structural element. In frame structures, such as
reinforced concrete frames, masonry may be used as infill. While the bare frame itself is able to carry the loads when it comes to seismic events, the infilled frame is not able to warp freely due to the constrained movement. This restraint results in a complex interaction between the infill and the surrounding frame, which may lead to severe damage to the infill as well as the surrounding frame. The interaction is studied in different projects and effective approaches for the description of the behavior are still lacking. Experimental programs are usually quite expensive, while numerical models, once validated, do offer an efficient approach for the investigation of the interaction when horizontally loaded. In order to study the numerous parameters influencing the seismic load bearing behavior, numerical models may be used. Therefore, this contribution presents a numerical approach for the simulation of infill masonry in reinforced concrete frames. Both parts, the surrounding frame as well as the infill are represented by micro modelling approaches to correctly take into account the different types of failure. The adopted numerical model describes the inelastic behavior of the system, as indicated by the obtained results of the overall structural response as well as the formation of damage in the infilled wall. Comparison of the numerical and experimental results highlights the valuable contribution of numerical simulations in the study and design of infilled frames. As damage of the infill masonry may occur in-plane due to the interaction as well as out-of-plane due to the low vertical load, both directions of loading are investigated.
Entscheidungsunterstützung bei der Gestaltung der betrieblichen Energieversorgung und -nutzung
(1998)
In diesem Paper wird die Entwicklung und Evaluation eines grafischen Regeleditors für das Erstellen von „Smart Living Environments“-Services vorgestellt. Dafür werden zunächst die Deduktion und Implementierung des grafischen Regeleditors erläutert. Anschließend wird eine Probandenstudie vorgestellt, in welcher der Mehrwert bezogen auf die Aspekte Zeit, Fehleranfälligkeit und Gebrauchstauglichkeit festgestellt wird.
During the development of a Competence Developing Game’s (CDG) story it is indispensable to understand the target audience. Thereby, CDGs stories represent more than just the plot. The Story is about the
Setting, the Characters and the Plot. As a toolkit to support the
development of such a story, this paper introduces the UserFocused Storybuilding (short UFoS) Framework for CDGs. The Framework and its utilization will be explained, followed by a description of its development and derivation, including an empirical study. In addition, to simplify the Framework use regarding the CDG’s target audience, a new concept of Nine Psychographic Player Types will be explained. This concept of Player Types provides an approach to handle the differences in between players during the UFoS Framework use. Thereby,
this article presents a unique approach to the development of
target group-differentiated CDGs stories.
This paper introduces a Competence Developing Game (CDG) for the purpose of a cybersecurity awareness training for businesses. The target audience will be discussed in detail to understand their requirements. It will be explained why and how a mix of business simulation and serious game meets these stakeholder requirements. It will be shown that a tablet and touchscreen based approach is the most suitable solution. In addition, an empirical study will be briefly presented. The study was carried out to examine how an interaction system for a 3D-tablet based CDG has to be designed, to be manageable for non-game experienced employees. Furthermore, it will be explained which serious content is necessary for a Cybersecurity awareness training CDG and how this content is wrapped in the game
There are different types of games that try to make use of the motivation of a gaming situation in learning contexts. This paper introduces the new terminology ‘Competence Developing Game’ (CDG) as an umbrella term for all games with this intention. Based on this new terminology, an assessment framework has been developed and validated in scope of an empirical study. Now, all different types of CDGs can be evaluated according to a defined and uniform set of assessment criteria and, thus, are comparable according to their characteristics and effectiveness.
KNX is a protocol for smart building automation, e.g., for automated heating, air conditioning, or lighting. This paper analyses and evaluates state-of-the-art KNX devices from manufacturers Merten, Gira and Siemens with respect to security. On the one hand, it is investigated if publicly known vulnerabilities like insecure storage of passwords in software, unencrypted communication, or denialof-service attacks, can be reproduced in new devices. On the other hand, the security is analyzed in general, leading to the discovery of a previously unknown and high risk vulnerability related to so-called BCU (authentication) keys.
Residential and commercial buildings account for more than one-third of global energy-related greenhouse gas emissions. Integrated multi-energy systems at the district level are a promising way to reduce greenhouse gas emissions by exploiting economies of scale and synergies between energy sources. Planning district energy systems comes with many challenges in an ever-changing environment. Computational modelling established itself as the state-of-the-art method for district energy system planning. Unfortunately, it is still cumbersome to combine standalone models to generate insights that surpass their original purpose. Ideally, planning processes could be solved by using modular tools that easily incorporate the variety of competing and complementing computational models. Our contribution is a vision for a collaborative development and application platform for multi-energy system planning tools at the district level. We present challenges of district energy system planning identified in the literature and evaluate whether this platform can help to overcome these challenges. Further, we propose a toolkit that represents the core technical elements of the platform. Lastly, we discuss community management and its relevance for the success of projects with collaboration and knowledge sharing at their core.
Im Rahmen von Ermüdungsanalysen ist nachzuweisen, daß die thermisch bedingten fortschreitenden Deformationen begrenzt bleiben. Hierzu ist die Abgrenzung des Shakedown-Bereiches (Einspielen) vom Ratchetting-Bereich (fortschreitende Deformation) von Interesse. Im Rahmen eines EU-geförderten Forschungsvorhabens wurden Experimente mit einem 4-Stab-Modell durchgeführt. Das Experiment bestand aus einem wassergekühlten inneren Rohr und drei isolierten und beheizbaren äußeren Probestäben. Das System wurde durch alternierende Axialkräfte, denen alternierende Temperaturen an den äußeren Stäben überlagert wurden, belastet. Die Versuchsparameter wurden teilweise nach vorausgegangenen Einspielanalysen gewählt. Während der Versuchsdurchführung wurden Temperaturen und Dehnungen zeitabhängig gemessen. Begleitend und nachfolgend zur Versuchsdurchführung wurden die Belastungen und die daraus resultierenden Beanspruchungen nachvollzogen. Bei dieser inkrementellen elasto-plastischen Analyse mit dem Programm ANSYS wurden unterschiedliche Werkstoffmodelle angesetzt. Die Ergebnisse dieser Simulationsberechnung dienen dazu, die Shakedown-Analysen mittels FE-Methode zu verifizieren.
The replacement of existing spillway crests or gates with labyrinth weirs is a proven techno-economical means to increase the discharge capacity when rehabilitating existing structures. However, additional information is needed regarding energy dissipation of such weirs, since due to the folded weir crest, a three-dimensional flow field is generated, yielding more complex overflow and energy dissipation processes. In this study, CFD simulations of labyrinth weirs were conducted 1) to analyze the discharge coefficients for different discharges to compare the Cd values to literature data and 2) to analyze and improve energy dissipation downstream of the structure. All tests were performed for a structure at laboratory scale with a height of approx. P = 30.5 cm, a ratio of the total crest length to the total width of 4.7, a sidewall angle of 10° and a quarter-round weir crest shape. Tested headwater ratios were 0.089 ≤ HT/P ≤ 0.817. For numerical simulations, FLOW-3D Hydro was employed, solving the RANS equations with use of finite-volume method and RNG k-ε turbulence closure. In terms of discharge capacity, results were compared to data from physical model tests performed at the Utah Water Research Laboratory (Utah State University), emphasizing higher discharge coefficients from CFD than from the physical model. For upstream heads, some discrepancy in the range of ± 1 cm between literature, CFD and physical model tests was identified with a discussion regarding differences included in the manuscript. For downstream energy dissipation, variable tailwater depths were considered to analyze the formation and sweep-out of a hydraulic jump. It was found that even for high discharges, relatively low downstream Froude numbers were obtained due to high energy dissipation involved by the three-dimensional flow between the sidewalls. The effects of some additional energy dissipation devices, e.g. baffle blocks or end sills, were also analyzed. End sills were found to be non-effective. However, baffle blocks with different locations may improve energy dissipation downstream of labyrinth weirs.