Active Fluid Borne Noise Reduction for Aviation Hydraulic Pumps

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, basic silencers like inline expansion chambers and Helmholtz-Resonators are state-of-the-art 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 this 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 is further simplified here and proposed as integral feature of future “smart pumps”

Active Fluid Borne Noise Reduction for Aviation Hydraulic Pumps

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, basic silencers like inline expansion chambers and Helmholtz-Resonators are state-of-the-art 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 this 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 is further simplified here and proposed as integral feature of future “smart pumps”

Enhanced toolbox for the combined analysis of fluid- and structure borne-noise of hydraulic systems

Today’s available softwarepackages 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)inhydraulic 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 FSI-model 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. Hencesolutions with minimum hardware efforts are preferred. In this context, theproposed 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

Active Fluid Borne Noise Reduction for Aviation Hydraulic Pumps

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, basic silencers like inline expansion chambers and Helmholtz-Resonators are state-of-the-art 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 this 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 is further simplified here and proposed as integral feature of future “smart pumps”