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Item type:Publication, Access status: without files , Enhanced toolbox for the combined analysis of fluid-And structure-borne noise of hydraulic systemsToday's available software packages that feature dedicated hydraulic system noise analysis capabilities focus on the Fluid- Borne Noise (FBN) prediction in frequency or time domain. However, some noise sensitive hydraulic installation areas, like light weight structures in aviation, drive the development of an extended toolbox that also covers the prediction of Structure- Borne Noise (SBN) and Fluid-Structure-Interaction (FSI) in hydraulic systems. This conference contribution presents the concept and design of such a toolbox. It is implemented in a Matlab Simulink/ Simscape environment by FBN-, SBN-And FSImodel libraries. For a given study case a simulation model is generated using elements from these libraries. The simulation results are experimentally validated using a dedicated hydraulic system noise test rig. It features a rotary valve as FBN source and a pipe system equipped with dynamic pressure transducers for FBN detection and acceleration sensors for SBN detection. The analysis capabilities of such a toolbox are considered beneficial in particular for future (pre-/re-) design projects in the aviation environment, which hold 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 onboard devices. Hence solutions with minimum hardware efforts are preferred. In this context, the proposed toolbox can be used for a combined tuning of type and location of standard/simple FBN silencers together with type and location of SBN effecting pipe clamps in order to optimize the overall system noise pattern towards an increased equipment durability and passenger comfort.Publicationtype: Conference Paper88 - 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