Gas–liquid coupling fluid pulsation attenuator: Theoretical and experimental studies

In response to low-frequency fluid pulsation suppression demand in ship hydraulic pipeline systems, a gas–liquid coupling type fluid pulsation attenuator (GLC-FPA) is proposed. Its structure can be viewed as a bladder structure embedded inside traditional Helmholtz fluid pulsation attenuators (H-FPA) cavity. Based on the gas–liquid coupling principle, the GLC-FPA can balance both low-frequency pulsation suppression and compactness requirements. First, the neck impedance and transmission loss models of the GLC-FPA are constructed using the modal matching method and verified through finite element simulation. Then, the pulsation suppression mechanism and parametric studies are conducted. The results indicate that for the same size, the GLC-FPA significantly improved low-frequency pulsation suppression compared to the H-FPA. Further, treating the GLC-FPA as a cell, we propose a GLC-FPA-based periodic pipeline structure based on phononic crystal theory, whose the band gap distribution characteristics are studied. The results show that the periodic pipeline structure could significantly increase the fluid pulsation suppression bandwidth and enjoys strong robustness. Finally, the prototype experiments are carried out to verify the transmission loss characteristics of the GLC-FPA and the periodic pipeline structure. The proposed GLC-FPA has great engineering application prospects, and GLC-FPA-based periodic pipe structure provides new implementation paths for quiet hydraulic pipeline systems.