Research on the attenuation characteristics of a Helmholtz type hydraulic silencer (Influence of a volume and neck geometry on the attenuation characteristics)

Abstract

The noise and vibration caused by pressure pulsation are one of detrimental problems in hydraulic systems. A Helmholtz type hydraulic silencer, which is based on the resonant phenomena of a mass-spring-damper system for its attenuate principle, is known as one of the most practical silencers in the hydraulic systems. In the previous researches, the transmission loss characteristics of the Helmholtz type hydraulic silencer were modeled by a distributed parameter model. However, in the design case that the ratio of the length and diameter L/D of the cylindrical volume is smaller, the resonance frequency of the existing model begins to deviate from the experimental results and the disparity increases with decreasing the ratio of L/D. The purpose of this research is to clarify the influence of a neck and volume geometry on the attenuation characteristics. In particular, a mathematical model that considers the flow for the radial direction of the cylindrical volume is newly proposed for the design case that L/D is smaller. The transmission loss characteristics of the Helmholtz type hydraulic silencer are investigated theoretically for both the proposed model and existing models. In addition, the experimental examination of the influence of volume geometry on the attenuation characteristics is carried out in order to verify the theoretical investigations.