Investigation On Acoustic Propagation Characteristics In Pipe And The Noise Source Evaluation Of Pipeline System

As the development of vibration and noise reduction,the noise of propeller and engines are effectively controlled,the seawater pipe system.It is an important link for underwater vehicle acoustic stealth to restrain the noise of seawater pipe system,so it is necessary to research the noise of elastic fluid-filled pipe.This paper summed the low of noise in pipe system from two aspects: the acoustic propagation in elastic fluid-filled pipe and the evaluation of the noise source of pipe system.This paper firstly carry out research on the acoustic propagation of elastic fluid-filled pipe.Deduce the sound field in liquid shell of pipe,then finish the deduction in elastic shell of pipe.Normal mode wave frequencies,axial transmission rules,radial distribution rules are analyzed.The numerical simulation of pipe model is carried out through the acoustic simulation software ACTRAN,the simulation results of the first three order modal frequencies and the sound pressure distribution in the pipe were compared with the theoretical results.Finally,the propagation characteristics in elastic fluid-filled pipe were experimentally verified by an experiment of acoustic propagation in elastic fluid-filled pipe.The results of the study show that: The distribution of sound filed along the radial direction in the elastic fluid-filled pipe follows the rule of Bessel's function,in the pipe,sound which is above the first cut-off frequency can propagate along the axis through the liquid,sound which is below the first cut-off frequency can only propagate through the vibration of shell.In this paper,an experimental platform for noise characters of seawater pipe system was set up in a reverberation pool,measured the noise of seawater pipe system by reverberation and direct method,according to the measurement results,the noise of seawater pipe system and the noise sources are evaluated.Hydrodynamic noise was evaluated through the water supply of high tank;pulsating pressure was evaluated through the combination of pump and hose;structural noise caused by various structural parts was evaluated through measuring the insertion loss.The results show that: pulsating pressure and the vibration of pipe wall structure are the main noise sources of the seawater pipe system,Hydrodynamic noise contributes only a little to the noise of whole pipe system,which is a secondary noise source.