Study On The Design And Experiment Of Large Diameter Water Silencer

Centrifugal pump and valve are the principal noise sources in seawater pipeline system. The flow-noise is radiated from the pipeline exits, and then affects seriously the hiding ability of warships, and has more influence on warship working enviroment. This paper invenstigates the generating mechanisms of flow-noise in seawater pipeline, and introduces several control methods. To control and isolate the flow-noise to radiaion from the pipeline exits, it is one of the widely used methods to install water silencer on seawater pipeline. This paper aims to design a large diameter water silencer which will be installed in a limited space. If the structure of reactive water silencer is adopted, the total volume of the water silencer will be too big, so this paper puts forward the structure of bladder type silencer with the nominal diameter DN200. Because this structure has the bladder outside of the bore hole tube, this water silencer is simplificated to be a perforated tube dissipative silencer in the numerical simulation, a one-dimensional analytical approach and a three-dimensional substructure boundary element approach are developed to predict and analyze the acoustic attenuation performance of the silencers. A real configuration of water silencer is created by ANSYS and the noise attenuation (transmission loss) is determined by the numerical simulation softwares-SYSNOIS. Meanwhile the flow dynamic (pressure drop) characteristics of water silencers is also calculated. According to the experiment requests of study, the test-bed of DN200 seawater pipeline system is set up, which is 1:1 scale and can imitate the really dynamic characteristic of the sea water pipeline system. This experiment is under the noise source of pump and valve to examine the acoustic characterstics and fluid dynamiccharacteristics of the water silencer .The result of the experiment verifies the conclusion of the theoretical simulation , and shows that the tightly packed structure has a satisfactory acoustic attenuation performance in a wide frequency range and a very low resistance loss. The developed silencer is applicable for the large diameter pipeline to attenuate the noise of pump and valves.