Research on a Helmholtz type hydraulic silencer with a flat vessel (Influence of an elastic deformation of the upper and lower vessel wall on the attenuation characteristics)

Abstract

In fluid power systems, a Helmholtz type hydraulic silencer is often utilized in order to attenuate pressure pulsations, which are detrimental to the system because of the vibration and noise that they generate. The silencer has the important feature that it is effective within a narrow band range around the resonance frequency. Therefore, it is very useful to be able to predict the attenuation characteristics by means of a mathematical model. Previous research has shown that there are noticeable discrepancies between the experimental values and calculated results when the ratio of the volume length L to diameter D is comparatively small. In this paper, a novel distributed parameter model was proposed in order to examine these discrepancies. The mathematical model was derived by taking into account the elastic deformation on the upper and lower vessel walls of a Helmholtz silencer with a flat volume. The analysis revealed that the resonance frequency of the silencer is reduced by a reduction in the volume length or by a reduction in the cover thickness. The reason for this is the reduction of the effective bulk modulus. In addition, experimental work was conducted to examine the attenuation characteristics under various conditions. The experimental results were found to correspond to the mathematical model qualitatively.

Keywords

• helmholtz silencer
• attenuation characteristics
• hydraulic system
• pressure pulsation
• bulk modulus