Attenuator for fluid pulsation in aircraft hydraulic systems based on gas-liquid coupling principle

As high demands of reliability and safety for aircraft hydraulic systems, the flow ripples caused by the aircraft hydraulic piston pump may lead to pipe vibration and components’ damage, which becomes the limitation of the high system reliability and long system lifetime. The attenuator utilized in the aircraft hydraulic system may demand wide frequency range, wide temperature range, effective attenuation effect and compact design, which are very challenging for the traditional attenuators. This paper presents the gas-liquid coupling principles theoretically, and proposes a novel fluid pulsation attenuator for wide range of frequencies and temperature. The mathematic model for the attenuator is established, and the design principles of the frequency range and temperature range are studied, and the positions of its installation are also studied. The prototype of attenuator is developed, and experiments are carried out on the aircraft hydraulic pump. The experimental results show that the attenuator has effective attenuation effect at frequency range from 394.2 Hz to 1 540 Hz, and the largest insertion loss value could reach up to 29.6 dB. At ambient temperature, the reduction rate could reach up to 75.7% in the time domain and 89.3% in the frequency domain; at high temperature, the reduction rate could reach up to 68.0% in time domain and 88.0% in frequency domain. The principles and model proposed in this work are proven to be effective and accurate, and the attenuation effects are validated in wide range of frequencies and temperature.