Study On Fluid-solid Coupling Lateral Vibration Characteristics Of Bare Gas Pipeline

Gas pipeline is an essential infrastructure in industrial energy,connecting the main artery of national transport resources,is an important support in the country's economic development.The pipeline system will vibrate and produce noise pollution due to the interaction between the fluid medium and the pipeline in the gas pipeline.Serious coupling vibration will lead to the damage of the pipeline system.Once the pipe system is damaged,it will cause gas leakage or even explosion in the pipe,which not only brings certain loss and harm to economy and environment,but also threatens people's life and property safety.Therefore,it is of great significance to study the fluid-solid dynamic characteristics of gas pipeline.This paper studies the influence of different factors on the vibration characteristics of buried pipeline system in goaf subsidence area,which is completely exposed to the natural environment.The main research contents include:(1)The nonlinear fluid-solid coupling lateral vibration model of pipeline is established.(2)The influence of different parameters on pipeline vibration characteristics under three working conditions is studied.(3)The influence of random foundation movement on the displacement response and stress of pipeline is studied.In this paper,the differential equation of fluid-solid coupled transverse vibration is established by using Hamilton's principle.Secondly,according to the actual support situation at both ends of the exposed pipe body,the pipes are respectively simplified into simply supported pipe model,cantilever pipe model and fixed supported pipe model.MATLAB software is used to analyze the influence of fluid factors,geometric factors and temperature change on the natural frequency of the pipe under three working conditions.Finally,ANSYS Workbench finite element software is used to analyze the influence of random load on the displacement response and stress of pipeline.By studying the transverse vibration characteristics of fluid-structure coupling of pipeline,the following conclusions are drawn:(1)In three working conditions,the natural frequency of pipeline increases with the increasing of external diameter of pipeline,and the influence of fluid velocity on the natural frequency of pipeline can be ignored in the range of engineering velocity.(2)In simply supported and cantilever pipeline vibration system,the natural frequency decreases with the increasing of pipe length.For the vibration system offixed pipe,the natural frequency decreases first and then increases slowly with the increase of pipe length.(3)In the vibration system of simply supported pipeline and fixed supported pipeline,the natural frequency decreases with the increasing of fluid pressure or temperature change.The vibration law of cantilever pipeline is just the opposite.(4)When the pipe is slender or the temperature change is large,the simply supported pipe and the fixed supported pipe will buckle,which should be avoided in the engineering practice.(5)The amplitude of the middle point deflection of the pipe increases with the increasing of the fluid velocity,the pipe length and the temperature change,and decreases with the increasing of the outer diameter.The fluid pressure has no obvious influence on the amplitude of the middle point of the pipe.(6)Under the action of random load,the vibration displacement of the cantilever pipeline at the free end is the maximum,and the stress at the fixed end is the maximum.Under the action of random load,the stress of simply supported and fixed supported pipelines is the maximum at the restraint end,and the displacement at the quarter distance from the restraint end is the maximum.