Study On The Vibration Characteristics Of The Typical Pipeline Influenced By The Pressure Fluctuation Of The Ship's Drain System

Flow pipeline is an important part of vessels drain system,which drains water from the cabin or inhals water from the outside.The ship drain system is of great significance for the whole ship to operate normally.However,there is inherent pressure pulsation which will stimulate the pipe to produce vibration.When the vibration is strong,it will produce vibration noise and cause the pipe damage.In this paper,the vibration characteristics of the pipeline under pressure pulsation were studied by using the method of simulation and experiment.The working characteristics of the plunger pump were analyzed,which was the foundation for the study of the pipeline vibration.Based on the Timoshenko beam model,a mathematical model of fluid-structure coupling vibration in general pipe was established.The model considered the Poisson coupling and connection coupling.The axial vibration,radial vibration equation of a straight pipe and continuity equation and momentum equation of water were derived.The velocity and pressure of the flow field and the stress and displacement of the pipe in the steady state were studied on the ANSYS Workbench using the bidirectional fluid-structure coupling model.The stress and deformation of the pipe under the conditions of different load,different pulsation frequency and different pressure pulsation rate were studied.The vibration state of pipeline excited by different frequencies was studied by harmonic response analysis method.The vibration of the pipeline under the different load and pressure pulsation rate was studied on the constructed ship hydrophobic system simulation platform,and the results were compared with the simulation results.According to the simulation and test results,it was found that with the increase of the load and pressure pulsation rate,the vibration of the pipe was strengthened.It wasfound that the vibration acceleration became larger with the increase of the pulse frequency by simulation,but the deformation was related to the natural frequencies,and the vibration was distributed symmetrically near the natural frequency.The vibration characteristics of the drainage pipeline under pressure pulsation could provide a basis for reducing the vibration and noise.