| Autor(en) | Kauth, Felix | Maroldt, Niklas | Seume, Jörg |
|---|---|
| Titel | Experimental Validation of a Compact Mixed-Flow Compressor for an Active High-Lift System |
| Herausgeber | International Scientific Conference on High Speed Turbomachines and Electrical Drives (HSTED), Saint Petersburg, Russia, 2019 |
| Erscheinungsjahr | 2019 |
| Abstract | Compact, electrically-driven compressors are a core component of a novel active high-lift system for future commercial aircraft. A newly-developed aeromechanical optimization process was used to design the compressor stage. The optimization resulted in an unusual mixed-flow compressor design with very low aspect ratio blades and a high rotational speed of up to 60,000 rpm. Due to the unusual design, experimental validation of the performance predictions by means of CFD is necessary. This paper presents the first experimental results obtained using a preliminary prototype at part-speed, i.e. rotational speeds from 20,000 to 30,000 rpm. The experimentally-determined pressure ratios deviate up to 1.5 %, the polytropic efficiencies up to 4 percentage points from the CFD predictions. Besides the deficiencies of available turbulence models, the underestimation of overall losses is presumably due to the omission of the volute in the CFD model. An experimental validation of the CFD predictions at full-speed is under way. |
| Autor(en) | Bartelt, Michael | Laguna, Juan D. | Seume, Jörg |
|---|---|
| Titel | Synthetic Sound Source Generation for Acoustical Measurements in Turbomachines |
| Herausgeber | ASME Turbo Expo, San Antonio, TX, USA, 2013 |
| Erscheinungsjahr | 2018 |
| Abstract | One of the greatest challenges in modern aircraft propulsion design is the reduction of the engine noise emission in order to develop quieter aircrafts. In the course of a current research project, the sound transport in low pressure turbines is investigated. For the corresponding experimental measurements, a specific acoustic excitation system is developed which can be implemented into the inlet of a turbine test rig and into an aeroacoustic wind tunnel. This allows for an acoustic mode generation and a synthesis of various sound source patterns to simulate typical turbomachinery noise sources such as rotor-stator interaction, etc. The paper presents the acoustical and technical design methodology in detail and addresses the experimental options of the system. Particular attention is paid to the design and the numerical optimization of the acoustic excitation units. To validate the sound generator during operation, measurements are performed in an aeroacoustic wind tunnel. For this purpose, an in-duct microphone array with a specific beamforming algorithm for hard-walled ducts is developed and applied to identify the source locations. The synthetically excited sound fields and the propagating acoustic modes are measured and analyzed by means of modal decomposition techniques. The measurement principles and the results are discussed in detail and it is shown that the intended sound source is produced and the intended sound field is excited. This paper shall contribute to help guide the development of excitation systems for aeroacoustic experiments to better understanding the physics of sound propagation within turbomachines. |
| Autor(en) | Kauth, Felix | Narjes, Gerrit | Müller, Jan | Mertens, Axel | Ponick, Bernd | Seume, Jörg |
|---|---|
| Titel | Electrically driven, Compact, Transonic Mixed-Flow Compressor for Active High-Lift Systems in Future Aircraft |
| Herausgeber | GPPS Montreal 2018 |
| Erscheinungsjahr | 2018 |
| Abstract | This paper gives an overview of the interdisciplinary design process of an electrically-powered high-lift system for future commercial aircraft, with a focus on the mixed-flow compressor performance. Based on the requirements of the high-lift system, a multi-objective optimization is used for the aero-mechanical design of the compressor stage. The demand for high pressure ratio and efficiency, together with the constrained installation space yields an unconventional mixed-flow compressor design with a transonic flow regime. To supply the required pressurized air for the high-lift system, rotational speeds of up to 60,000 rpm are necessary according to CFD analysis. A very compact integrated prototype of the compressor system is designed, including electrical machine and power electronics with high power-to-mass ratios. Performance predictions are validated at part load. To integrate the compressor stage into the prototype, some adjustments to the geometry become necessary. Additional CFD simulations reveal a big impact of the new inlet duct on the compressor performance due to inlet flow distortion. It is assumed that a fully-integrated design process, which includes all relevant interdependencies of the different components, would yield a better overall system design. |
| Autor(en) | Müller, Jan | Bensmann, Astrid | Bensmann, Boris | Fischer, Tore | Kadyk, Thomas | Narjes, Gerrit | Kauth, Felix | Ponick, Bernd | Seume, Jörg | Krewer, Ulrike | Hanke-Rauschenbach, Richard | Mertens, Axel | Narjes, Gerrit |
|---|---|
| Titel | Design Considerations for the Electrical Power Supply of Future Civil Aircraft with Active High-lift Systems |
| Herausgeber | MDPI Energies |
| Erscheinungsjahr | 2018 |
| Abstract | Active high-lift systems of future civil aircraft allow noise reduction and the use of shorter 1 runways. Powering high-lift systems electrically has a strong impact on the design requirements 2 for the electrical power supply of the aircraft. The active high-lift system of the reference aircraft 3 design considered in this paper consists of a flexible leading-edge device together with a combination 4 of boundary-layer suction and Coanda-jet blowing. Electrically driven compressors distributed 5 along the aircraft wings provide the required mass flow of pressurized air. Their additional loads 6 significantly increase the electric power demand during take-off and landing, which is commonly 7 provided by electric generators attached to the aircraft engines. The focus of the present study is 8 a feasibility assessment of alternative electric power supply concepts to unburden or eliminate the 9 generator coupled to the aircraft engine. For this purpose, two different concepts using either fuel 10 cells or batteries are outlined and evaluated in terms of weight, efficiency, and technology availability. 11 The most promising, but least developed alternative to the engine-powered electric generator is the 12 usage of fuel cells. The advantages are high power density and short refueling time, compared to the 13 battery storage concept. |
| Autor(en) | Narjes, Gerrit | Kauth, Felix | Müller, Jan | Mertens, Axel | Seume, Jörg | Ponick, Bernd |
|---|---|
| Titel | High-Speed Permanent Magnet Synchronous Machine for Short-Term Operation in an Electrically Powered High-Lift System |
| Herausgeber | AIAA/IEEE Electric Aircraft Technologies Symposium, Cincinnati, OH, USA, 2018 |
| Erscheinungsjahr | 2018 |
| Abstract | The noise footprint of aircraft at airports is one of the major reasons, why many of these facilities are located on the outskirts of cities instead of near the city centre. One approach to reduce this footprint is to increase the lift coefficient by using electrically powered high-lift systems (EPHLS) which are located near each wing’s flaps. Each system consists of a turbo compressor which is directly driven by a permanent magnet synchronous machine at a maximum rotational speed of 60,000 rpm and a maximum required power of 80 kW. Current investigations focus on the enhancement of the aircraft’s take-off and landing which limit the operating time of the EPHLS to a maximum of 240 s. This paper will highlight the design of the three main components of the EPHLS, namely SiC converter, electrical machine, and turbo compressor. The machine design is significantly influenced by the short operating time, thus moving the critical thermal parameters to the transient regime of the temperature characteristics. The thermal parameters for this machine design will be discussed and iterated for several scaled power levels, as the EPHLS consists of several turbo compressors along the wing span with different ratings. These are thermally characterized and compared to conclude what the scaling of electrical machines for short-term operation means for the thermal characteristic parameters. In the end, a different reference design point for the electrical machine is identified, a fast and simple way for the scaling of electrical machine designs for short-term operation with respect to power is found and conclusions for the design and scaling of combined power electronics, electrical machine, and turbo compressor systems are drawn. |
| Autor(en) | Du, Juan | Seume, Jörg |
|---|---|
| Titel | Design of Casing Treatment on a Mixed-Flow Compressor |
| Herausgeber | Proceedings of ASME Turbo Expo 2017, Charlotte, NC, USA, 2017 |
| Erscheinungsjahr | 2017 |
| Abstract | Casing treatments (CTs) have been proved to beneficially affect the behavior of tip clearance flow and compressor stability. This paper presents the design of casing treatment for a mixed-flow compressor with a very small tip gap of 0.1mm. In the first part, the potential of applying two traditional types of casing treatments, i.e. circumferential grooves and axial slots, to enhance the stability of a mixed-flow compressor is investigated. The flow details in the reference compressor with smooth casing are examined first. It is found that a separating vortex is formed due to the reversed flow on the blade suction side near the rotor trailing edge at the near-stall point. It is supposed to be responsible for the decrease in total pressure ratio when the compressor approaches to stall. The numerical stall, i.e. the breakdown of the simulation, is initiated from the spillage of tip leakage flow over the rotor blade leading edge. The effect of circumferential grooves on the compressor performances is not remarkable. The implement of axial slots ameliorates the total pressure ratio and extend the flow range substantially, but with higher efficiency penalty than the circumferential grooves. The recirculation formed in the axial skewed slots eliminates the separation vortex near the trailing edge and suppresses the spillage of the tip leakage flow forward the rotor leading edge simultaneously. The axial skewed slots are further designed and optimized numerically by DoE (Design of Experiments). As DoE factors the axial length, the height, the open area ratio, and the number per blade passage of the slots are varied. Their effects on the two target values stall margin and polytropic efficiency are investigated. The plot of stall margin improvement (SMI) with a function of the peak efficiency improvement (PEI) indicates that the SMI changes reversely with the PE. There are two trends in the correlation curves of SMI with PE. For the configurations with the open area ratio of 20%, the SMI is changed from 9% to 23% with 1% decrease in PE by varying other three factors. For the CTs with the open area ratio of 60% the augment in SMI from 17.8% to 26.3% produces extra efficiency loss of 4.2%. |
| Autor(en) | Du, Juan | Seume, Jörg |
|---|---|
| Titel | Design of Casing Treatment on a Mixed-Flow Compressor |
| Herausgeber | Proceedings of ASME Turbo Expo 2017, Charlotte, NC, USA |
| Erscheinungsjahr | 2017 |
| Abstract | Casing treatments (CTs) have been proved to beneficially affect the behavior of tip clearance flow and compressor stability. This paper presents the design of casing treatment for a mixed-flow compressor with a very small tip gap of 0.1mm. In the first part, the potential of applying two traditional types of casing treatments, i.e. circumferential grooves and axial slots, to enhance the stability of a mixed-flow compressor is investigated. The flow details in the reference compressor with smooth casing are examined first. It is found that a separating vortex is formed due to the reversed flow on the blade suction side near the rotor trailing edge at the near-stall point. It is supposed to be responsible for the decrease in total pressure ratio when the compressor approaches to stall. The numerical stall, i.e. the breakdown of the simulation, is initiated from the spillage of tip leakage flow over the rotor blade leading edge. The effect of circumferential grooves on the compressor performances is not remarkable. The implement of axial slots ameliorates the total pressure ratio and extend the flow range substantially, but with higher efficiency penalty than the circumferential grooves. The recirculation formed in the axial skewed slots eliminates the separation vortex near the trailing edge and suppresses the spillage of the tip leakage flow forward the rotor leading edge simultaneously. The axial skewed slots are further designed and optimized numerically by DoE (Design of Experiments). As DoE factors the axial length, the height, the open area ratio, and the number per blade passage of the slots are varied. Their effects on the two target values stall margin and polytropic efficiency are investigated. The plot of stall margin improvement (SMI) with a function of the peak efficiency improvement (PEI) indicates that the SMI changes reversely with the PE. There are two trends in the correlation curves of SMI with PE. For the configurations with the open area ratio of 20%, the SMI is changed from 9% to 23% with 1% decrease in PE by varying other three factors. For the CTs with the open area ratio of 60% the augment in SMI from 17.8% to 26.3% produces extra efficiency loss of 4.2%. |
| Autor(en) | Kauth, Felix | Narjes, Gerrit | Müller, Jan | Seume, Jörg | Vasista, Srinivas | Müller, Thomas | Francois, Daniela | El Sayed, Yosef | Semaan, Richard | Behr, Christian | Schwerter, Martin | Leester-Schädel, Monika | Nolte, Felix | Giesecke, Daniel | Atalayer, Caglar | Radespiel, Rolf |
|---|---|
| Titel | Progress in Efficient High-Lift |
| Herausgeber | AIAA AVIATION Forum, 35th AIAA Applied Aerodynamics Conference, Denver, 2017 |
| Erscheinungsjahr | 2017 |
| Abstract | This paper presents some of the progress in research on efficient high-lift systems for future civil aircraft achieved by the Coordinated Research Centre CRC 880 sponsored by the German Research Foundation. Several new approaches to increasing the lift are applied as part of the design of a reference aircraft with short take-off and landing ca- pability: The numerically predicted positive effect of Coanda jet blowing at the trailing edge flap is validated in water tunnel experiments. Robust miniature pressure and hot- film sensors are developed for the closed-loop control of a piezo-actuated blowing lip. A flexible leading-edge device utilizes composite materials, for which new structural designs are developed. Additionally, a potential de-icing system, as well as a lightning-strike pro- tection are presented. A high power-density electrically driven compressor with a broad operating range is designed to provide the blowing airflow. Different propulsion systems for the reference aircraft are evaluated. An ultra-high bypass ratio engine is considered to be most promising, and thus a preliminary fan stage design process is established. The rotor dynamic influences of the engine on the aircraft structure are investigated through a hybrid approach using a multibody model and modal reduction. |
| Autor(en) | Müller, Jan | Mertens, Axel |
|---|---|
| Titel | Power Electronics Design for a direct-driven Turbo Compressor Used as Advanced High-Lift System in Future Aircraft |
| Herausgeber | IECON, Peking, 2017 |
| Erscheinungsjahr | 2017 |
| Abstract | This paper presents the 100kW air-cooled inverter design of a power train used for advanced high-lift systems in future aircrafts. To achieve additional high-lift during take-off and landing of a plane, air is blown out at the back flap of the wings using a turbo compressor directly driven by an electrical machine. Silicon Carbide (SiC) devices promise large savings in volume, weight and losses of the inverter, which results in a highly-integrated system. Furthermore, the intake air is used as coolant for the power electronics. Such a system with a high power density of 10.8 kW/l has been designed and implemented, and first tests were performed on a laboratory prototype. |
| Autor(en) | Narjes, Gerrit | Müller, Jan | Kauth, Felix | Seume, Jörg | Mertens, Axel | Ponick, Bernd |
|---|---|
| Titel | Kompakte elektrisch angetriebene Turbokompressoren für ein aktives Hochauftriebssystem künftiger Verkehrsflugzeuge |
| Herausgeber | E-MOTIVE Expertenform, Hannover, Deutschland, 2017 |
| Erscheinungsjahr | 2017 |
| Abstract | Steigende Passagierzahlen in der zivilen Luftfahrt gekoppelt mit den wachsenden Anforderungen an Flugzeuge hinsichtlich Schallemissionsreduzierung im Bereich des Flughafens erfordern die Untersuchung neuartiger Konzepte zur Erzeugung des Auftriebs. Der Sonderforschungsbereich 880 befasst sich mit verschiedenen Themenbereichen um die Lärmbelastung und den Treibstoffverbrauch künftiger Flugzeugtypen zu reduzieren. Ein Ansatz, der untersucht wird, stellt die Nutzung eines aktiven Hochauftriebssystems dar, das durch eine Kombination aus Grenzflächenabsaugung an der Tragflächenoberseite und Ausblasung an den hinteren Klappen durch Nutzung des Coanda-Effekts eine Steigerung des Auftriebs ermöglicht. Die Realisierung erfolgt durch sechs Kompressorsysteme pro Tragfläche, die aus einem Umrichter, einer permanentmagneterregten Synchronmaschine und einem Turbokompressor bestehen. Zur Reduzierung des benötigten Volumens und des Gewichts wird auf ein Getriebe verzichtet, was zu einer Anwendung mit hohen Drehzahlen und hohen Frequenzen führt. Zusätzlich dient lediglich die angesaugte Luft als Kühlmedium, um zusätzliche eingebrachte Masse durch ein Kühlsystem zu vermeiden. Die Leistungselektronik nutzt ein neuartiges Aufbaukonzept und erreicht eine Leistungsdichte von 10,8 kW/l beim Wechselrichter. Zusätzlich werden Silizium-Karbid-Halbleitermodule eingesetzt um die benötigten hohen Ausgangsfrequenzen zu realisieren und die Verlustleistung zu minimieren. Der Turbokompressor wird mit Hilfe automatisierter Optimierungsmethoden dimensioniert, was zu einem einstufigen Axialverdichter führt, der den erforderlichen Coanda-Strahl bereitstellt. Die elektrische Maschine treibt den Kompressor bei 60.000 min-1 mit einer Leistung von 80 kW an. Solch hohe Drehzahlen erfordern eine genaue Betrachtung der Rotormechanik und stellen hohe Ansprüche an die thermische Vorausberechnung. Da es sich um eine Flugzeuganwendung handelt geschieht die Dimensionierung für eine Kühlmediumtemperatur von 50 °C, um die Umgebungstemperaturen in wärmeren Regionen zu berücksichtigen. Durch das Hochdrehzahlkonzept und eine Auslegung im S2 Betrieb konnte eine Leistungsdichte des Motoraktivteils von 7 kW/kg erreicht werden. Dieser Beitrag soll die Komponenten des aktiven Hochauftriebssystems im Einzelnen vorstellen und einen Überblick über die Dimensionierung eines solchen Gesamtsystems liefern. Dies umfasst ebenfalls die während des Dimensionerungsprozesses entwickelte ganzheitliche Auslegungsmethodik. |
| Autor(en) | Teichel, Sönke | Verstraete, Tom | Seume, Jörg |
|---|---|
| Titel | Optimized Multidisciplinary Design of a Small Transonic Compressor for Active High-Lift Systems |
| Herausgeber | International Journal of Gas Turbine, Propulsion and Power Systems, Vol. 9, No. 2, pp- 19-26 |
| Erscheinungsjahr | 2017 |
| Abstract | This paper presents the methodology and results of a design optimization of a single stage, axial compressor. At the design point, the compressor achieves a total pressure ratio of 2.33 at a mass-flow rate of 1.11 kg/s. The compressor is part of an electrically powered active high lift system (AHLS) for future civil aircraft. An automated process using numerical models to evaluate aerodynamic performances and mechanical loads due to centrifugal forces is used. This evaluation process is coupled to an evolutionary algorithm to help investigate the design-space. A parameterization strategy was developed to cover a wide design-space, excluding unreasonable de- signs. The goal was to satisfy the challenging design requirements of high pressure ratio, high power density and limited rotation speed imposed by the AHLS. The resulting design of a highly loaded com- pressor is characterized by significant end-wall slope and low blade aspect ratios, resembling a mixed flow compressor. According to CFD analysis it is predicted to cover the required operating points at total-total, polytropic efficiencies higher than 80 %. |
| Autor(en) | Kauth, Felix | Narjes, Gerrit | Müller, Jan | Mertens, Axel | Ponick, Bernd | Seume, Jörg |
|---|---|
| Titel | Highly Integrated Electrically Driven Active High-Lift Compressor Systems for Future Civil Aircraft |
| Herausgeber | Greener Aviation Conference, Brussels, 2016 |
| Erscheinungsjahr | 2016 |
| Abstract | This paper presents the current status of the develop- ment of an electrically driven high-speed compressor for active high-lift systems (AHLS). A high-speed electrical machine with a high power-to-weight ratio was developed, which utilizes the compressor intake air as a coolant. The power electronics were designed with a new approach to reduce the required space. Furthermore, they are cooled by the intake air flow. Automatic optimization methods were applied to design a single-stage axial compressor that provides the required air flow for the Coanda jet. To obtain high pressure ratios with high efficiency, a new transonic design with a high radial velocity component was chosen. |
| Autor(en) | Narjes, Gerrit | Müller, Jan | Kauth, Felix | Seume, Jörg | Mertens, Axel | Ponick, Bernd | Müller, Jan |
|---|---|
| Titel | Design Considerations for an Electrical Machine Propelling a Direct Driven Turbo Compressor for use in Active High-Lift Systems |
| Herausgeber | ESARS itec, Toulouse, Frankreich, 2016 |
| Erscheinungsjahr | 2016 |
| Abstract | This paper presents the design approach of a power train used in an advanced high-lift system for future aircraft. Aircraft applications require an ultra-light and integrated design leading to an electrical machine with a high power to weight ratio of 2.82 kW/kg. To achieve additional high lift during take-off and landing, air is blown out at the back flaps of the aircraft wings using a turbo compressor which is directly driven by an inverter-fed electrical machine. The design of the power train and the electrical machine in particular is discussed under different aspects, e.g. the electromagnetic design and the mechanical demands including the selection of a feasible rotor armour. This paper identifies the interfaces between the different factors and describes their dependencies. |
| Autor(en) | Hurfar, Mandanna | Bartelt, Michael | Seume, Jörg |
|---|---|
| Titel | A Scaling Method for Modal Sound Propagation in Annular Ducts |
| Herausgeber | Proceedings of the ASME Turbo Expo 2015, Montréal, Canada, 2015 |
| Erscheinungsjahr | 2015 |
| Abstract | The interaction between stationary and rotating components is a major source of the noise emission of aircraft engines. Within the engine, the generated sound propagates in discrete pressure patterns, so-called spinning modes. In order to develop noise reduction technologies for these acoustic components, numerical as well as experimental investigations are carried out. In many cases however, the test rigs are geometrically and thermodynamically scaled in comparison to the turbomachines used in aircraft engines. The objective of this paper is to provide an analytical method to investigate the effect of scaling on the major properties of modal sound propagation in symmetric hard-walled annular ducts with a superimposed uniform axial flow. The potential of generating similar sound propagation properties in two ducts is assessed. For these purposes, the magnitude of the dominating modal group velocity vector, the corresponding axial component, and the angle relative to the duct axis are expressed in terms of the dimensionless parameters Mach number, Helmholtz number, and hub-to-tip ratio. In addition, the corresponding quantities of the wave vector are considered. With respect to these properties, it is shown that for a constant hub-to-tip ratio, modal sound propagation in two annular ducts is similar if the Mach number and Helmholtz number are identical. |
| Autor(en) | Hurfar, Mandanna | Bartelt, Michael | Seume, Jörg |
|---|---|
| Titel | A Scaling Method for Modal Sound Propagation in Annular Ducts |
| Herausgeber | Proceedings of the ASME Turbo Expo 2015, Montréal, Canada, 2015 |
| Erscheinungsjahr | 2015 |
| Abstract | The interaction between stationary and rotating components is a major source of the noise emission of aircraft engines. Within the engine, the generated sound propagates in discrete pressure patterns, so-called spinning modes. In order to develop noise reduction technologies for these acoustic components, numerical as well as experimental investigations are carried out. In many cases however, the test rigs are geometrically and thermodynamically scaled in comparison to the turbomachines used in aircraft engines. The objective of this paper is to provide an analytical method to investigate the effect of scaling on the major properties of modal sound propagation in symmetric hard-walled annular ducts with a superimposed uniform axial flow. The potential of generating similar sound propagation properties in two ducts is assessed. For these purposes, the magnitude of the dominating modal group velocity vector, the corresponding axial component, and the angle relative to the duct axis are expressed in terms of the dimensionless parameters Mach number, Helmholtz number, and hub-to-tip ratio. In addition, the corresponding quantities of the wave vector are considered. With respect to these properties, it is shown that for a constant hub-to-tip ratio, modal sound propagation in two annular ducts is similar if the Mach number and Helmholtz number are identical. |
| Autor(en) | Teichel, Sönke | Verstraete, Tom | Seume, Jörg |
|---|---|
| Titel | Optimized Multidisciplinary Design of a Small Transonic Compressor for Active High-Lift Systems |
| Herausgeber | Proceedings of International Gas Turbine Congress, Tokyo |
| Erscheinungsjahr | 2015 |
| Abstract | This paper presents the methodology and results of the optimized, multidisciplinary design of a small, single stage, axial compressor with a corrected mass-flow rate of about 1.11 kg/s and a total pressure ratio of up to 2.57 at the design point. The compressor is part of an electrically powered active high lift system (AHLS) for future civil aircraft. An automated process using numerical models to evaluate aerodynamic performances and mechanical loads due to centrifugal forces is used for the design. This valuation process is coupled to an evolutionary algorithm to help investigate the designspace. A parameterization strategy was developed to cover a wide design-space, excluding unreasonable designs. The goal was to satisfy the design requirements high pressure ratio, high power density and limited rotation speed imposed by the application of the AHLS. The resulting design of a highly loaded single stage axial compressor covers the operating points of the AHLS at efficiencies higher than 85%for lower mass-flow rates, while at higher mass-flow rates it drops to 80 %. |
| Autor(en) | Chahine, Christopher | Seume, Jörg | Verstraete, Tom |
|---|---|
| Titel | THE INFLUENCE OF METAMODELING TECHNIQUES ON THE MULTIDISCIPLINARY DESIGN OPTIMIZATION OF A RADIAL COMPRESSOR IMPELLER |
| Herausgeber | Proceedings of ASME Turbo Expo 2012, Proceedings of ASME Turbo Expo 2012 |
| Erscheinungsjahr | 2014 |
| Abstract | Aerodynamic turbomachinery component design is a very complex task. Although modern CFD solvers allow for a detailed investigation of the flow, the interaction of design changes and the three dimensional flow field are highly complex and difficult to understand. Thus, very often a trial and error approach is applied and a design heavily relies on the experience of the designer and empirical correlations. Moreover, the simultaneous satisfaction of aerodynamic and mechanical requirements leads very often to tedious iterations between the different disciplines. Modern optimization algorithms can support the designer in finding high performing designs. However, many optimization methods require performance evaluations of a large number of different geometries. In the context of turbomachinery design, this often involves computationally expensive Computational Fluid Dynamics and Computational Structural Mechanics calculations. Thus, in order to reduce the total computational time, optimization algorithms are often coupled with approximation techniques often referred to as metamodels in the literature. Metamodels approximate the performance of a design at a very low computational cost and thus allow a time efficient automatic optimization. However, from the experiences gained in past optimizations it can be deduced that metamodel predictions are often not reliable and can even result in designs which are violating the imposed constraints. In the present work, the impact of the inaccuracy of a metamodel on the design optimization of a radial compressor impeller is investigated and it is shown if an optimization without the usage of a metamodel delivers better results. A multidisciplinary, multiobjective optimization system based on a Differential Evolution algorithm is applied which was developed at the von Karman Institute for Fluid Dynamics. The results show that the metamodel can be used efficiently to explore the design space at a low computational cost and to guide the search towards a global optimum. However, better performing designs can be found when excluding the metamodel from the optimization. Though, completely avoiding the metamodel results in a very high computational cost. Based on the obtained results in present work, a method is proposed which combines the advantages of both approaches, by first using the metamodel as a rapid exploration tool and then switching to the accurate optimization without metamodel for further exploitation of the design space. |
| Autor(en) | Braunisch, Dirk | Ponick, Bernd | Bramerdorfer, Gerd |
|---|---|
| Titel | Combined Analytical–Numerical Noise Calculation of Electrical Machines Considering Nonsinusoidal Mode Shapes |
| Herausgeber | IEEE Transactions on Magnetics, Vol. 49, No. 4, 2013 |
| Erscheinungsjahr | 2013 |
| Abstract | This paper describes a calculation method for the electromagnetically excited noise of different types of rotating electrical machines. A numerically gained modal matrix of the stator is used for the analytical calculation of the surface's deflection and thus combines short calculation times of analytical methods with the accuracy of numerical calculations. Considering elliptic deformations due to nonsymmetrical pairs of eigenvectors, as especially occurring for small machines with few teeth, a time-stepping algorithm allows the examination of noncircular spatial harmonics of the deformation. An adapted analytical sound pressure calculation is appended. Finally, a comparison with a measurement of the surface oscillation validates the improved calculation method. |
| Autor(en) | Braunisch, Dirk | Ponick, Bernd | Bramerdorfer, Gerd |
|---|---|
| Titel | Combined Analytical–Numerical Noise Calculation of Electrical Machines Considering Nonsinusoidal Mode Shapes |
| Herausgeber | IEEE TRANSACTIONS ON MAGNETICS, VOL. 49, NO. 4, pp. 1407-1415 |
| Erscheinungsjahr | 2013 |
| Abstract | This paper describes a calculation method for the electromagnetically excited noise of different types of rotating electrical machines. A numerically gained modal matrix of the stator is used for the analytical calculation of the surface's deflection and thus combines short calculation times of analytical methods with the accuracy of numerical calculations. Considering elliptic deformations due to nonsymmetrical pairs of eigenvectors, as especially occurring for small machines with few teeth, a time-stepping algorithm allows the examination of noncircular spatial harmonics of the deformation. An adapted analytical sound pressure calculation is appended. Finally, a comparison with a measurement of the surface oscillation validates the improved calculation method. |
| Autor(en) | Seume, Jörg | Burnazzi, Marco | Schwerter, Martin | Behr, Christian | Rudenko, Anton | Schmitz, Andre | Dörbaum, Michael | Atalayer, Caglar |
|---|---|
| Titel | SFB 880 – Efficient High Lift |
| Herausgeber | 62nd DLRK, Stuttgart, Germany, 2013 |
| Erscheinungsjahr | 2013 |
| Abstract | The collaborative research center (Sonderforschungsbereich, abbreviated SFB) 880 investigates the fundamentals of high-lift generation for future civil aircraft, focusing on the fields of aeroacoustics, lift generation and flight dynamics. The present paper addresses the research on efficient lift generation which is denoted as Research Area B. The underlying research hypothesis of the present work is that further significant increases in lift generation of civil aircraft compared to the current state technology are possible using active lift systems. The investigated high-lift concept utilizes a combination of internally blown flaps and circulation control to achieve high flow turning over the wing. A flexible leading edge device for the wing without gap or step is designed to reduce noise generation and to increase the efficiency of the active blowing system. Further, closed-loop control of blowing is envisaged. The overall objective of the project is to design an active lift system that requires a minimum of additional engine power to generate the required lift. A multidisciplinary, collaborative approach is taken, combining the fields of aerodynamics, material science, microtechnology, turbomachinery and electrical engineering to obtain optimum performance of the overall lift generation system. The research progress during the first two years of this ongoing work is presented in this paper. |