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Item type:Publication, Access status: without files , Electro-hydraulic system architectures for MEA : comparison of central and zonal power packagesPublicationtype: Conference Presentation24 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Active fluid borne noise reduction for aviation hydraulic systems(Technische Universität Dresden, 2016-03); ; ; The aviation environment holds challenging application constraints for efficient hydraulic system noise reduction devices. Besides strong limits on component weight and size, high safety and reliability standards demand simple solutions. Hence, b silencers like inline expansion chambers and Helmholtz-Resonators are state-of-the aboard commercial aircrafts. Unfortunately, they do not meet today's noise attenuation aims regarding passenger comfort and equipment durability. Significant attenuation performance is expected from active concepts that generate anti-phase noise However, such concepts remain a long term approach unless related costs, e.g. due to additional power allocation and real-time control equipment can be avoided. In t paper an active fluid borne noise attenuation concept is discussed that accounts for the mentioned constraints. An aircraft hydraulic pump is considered as main noise source The active attenuator is an in-house rotary valve design. The basic feature is a known direct shaft coupling principle of pump and rotary valve, so no speed/ frequency control of the valve and no separate power supply are required. The common-shaft principle further simplified here and proposed as integral feature of future 'smart pumps'.Publicationtype: Conference Paper93 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Compact fluid-borne noise silencers for aviation hydraulic systemsThe aviation environment holds challenging application constraints for efficient hydraulic system noise reduction devices. Besides obligatory strong limits on component weight and size, the high safety and reliability standards demand simple and maintenance-free silencer solutions. Hence, basic Helmholtz-Resonators and inline expansion chambers are state-of-the-art aboard commercial aircrafts in service. Unfortunately, they do not meet today's noise attenuation performance aims regarding passenger comfort and equipment durability. Furthermore, production and installation costs have to be considered, plus particular aircraft operating conditions. Commercial aircrafts come with relatively high operating pressures of 210/350bar (3000/5000psi) and fluid-borne noise fundamental frequencies up to approximately 1200 Hz for some of the hydraulic pumps. This conference contribution discusses a new compact approach for an inline expansion chamber, named Disc- Silencer that accounts for the mentioned aviation constraints. The silencer chamber is designed as smooth expansion in only one radial direction relative to the connected piping. The perpendicular radial dimension is kept identical to the piping diameter. This results in a flat rectangular cross area of the flow passageway instead of a circular shape, enabling new options for installation and further incremental development. In this paper, the modelling and experimental validation of such an unconventional hydraulic silencer are presented.Publicationtype: Conference Paper244 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Architecture and Parameter Optimization for Aircraft Electro-Hydraulic Power Generation and Distribution Systems(2015-09-15); ; ; The All-Electric-Engine with only electrical power offtake is a main goal in aircraft system development. The use of electric-motor pumps instead of engine-driven pumps for powering the central hydraulic systems could be a part of this objective. Additionally, the concept would meet the incremental development strategy performed by the aerospace industry today and saves costs by using state-of-the-art hydraulic actuation technology. This paper describes a process for optimizing such systems regarding their architecture and design parameters. For this task a methodology for the hydraulic consumer allocation called OPAL is used and extended by an automatic power system sizing. Feasible allocations, called permutations, are determined on the basis of preliminary system safety assessments regarding multiple top failure events. In the next step an automated sizing of the permutations is performed based on simplified hydraulic load analyses. This enables a comparison of a large number of architectures in a very short time to optimize the electro-hydraulic system architecture. In the next part of the process a more detailed sizing of the electro-hydraulic system is performed for selected example architectures. Here a steady-state sizing of the power system is carried out with the Hamburg University of Technology tool ArOLab. The pipe network sizing is automated by using an optimization that finds a design that meets the performance requirements with a minimum of mass. The function is used to do a rapid evaluation of different design variables that influence the later system performance. The whole process is demonstrated by a test case study in which electro-hydraulic architectures are optimized for a mid-range aircraft.Publicationtype: Conference Paper79