Analytical Approach for Pressure Ripple Attenuation in Pressurized Bladder Style In-Line Hydraulic Noise Suppressors

Pressurized bladder style in-line hydraulic noise suppressor (bladder suppressor) is effective to attenuate the pressure ripple of the hydraulic systems and widely used in industry, but existing theoretical approaches which can analyse the pressure ripple attenuation exactly for bladder suppressor are poor in the literature and difficult to repeat. To address those shortcomings, based on the dynamic characteristics of the pipeline and the transfer matrix analysis method, this paper proposes a transfer matrix analytical approach (TMAA) and investigates the influences of the structural parameters of perforated tube and the precharged pressure of bladder suppressor on the pressure ripple attenuation. Dividing the model of bladder suppressor into 12 models which are similar to the model of a bladder accumulator is a critical step in the presented analytical approach. The results are as follows. The transmission loss (TL) calculated by the TMAA corresponds well with the published experimental result in the frequency below 400 Hz, and the difference between them is no more than 10dB in the frequency from 1500Hz to 5000Hz. In addition, the precharged pressure of bladder suppressor has little effected on the TL in the frequency upon 2000Hz, but the peak value of the TL has been moved from high frequency to low frequency when the precharged pressure increases within a certain pressure range. What's more, it is noted that the model considered the wall thickness is more consistent with the published data than the model without considering the wall thickness, and the hole diameter of the perforated tube also do significantly influence the TL in a large frequency band.

I. Introduction

Axial piston pumps have been widely used in hydraulic system because of their excellent stability, high working pressure and good applicability. However, they can generate significant pressure ripple which may decrease the performance of hydraulic system and product noise caused by fluid, while in hydraulic pipeline system, the fluid-borne noise interact with the system structure and causes vibration [1]. In order to weaken the fluid-borne noise of hydraulic systems, lots of pulsation attenuators have been presented, such as spring-loaded hydraulic suppressors [2], porous-concentric hydraulic mufflers [3], bladder accumulators [4] and Helmholtz attenuators [5], among which bladder accumulators and Helmholtz attenuators are categorized as the resonant pulsation attenuator.