Fluid-Solid Coupling Vibration Analysis And Software Simulation Of Pipes Conveying Fluid

Pipeline transportation is an economic,stable and safe transportation method using pipelines as a means of transportation,from macroscopic scale to microscopic scale.It is widely used in modern industrial fields such as biomedicine,ships and oceans,nuclear energy and minimally invasive medicine.But the flow pipeline in the process of work,due to the pipeline structure,fluid flow rate,external load and other factors caused by the fluid flow and fluid pressure changes in the pipe,which induces pipeline deformation,triggering pipeline vibration,and in serious cases even cause pipeline damage,fluid leakage and other problems,and then produce irreversible consequences.Therefore,in order to improve the safety and reliability of the flow transmission pipeline transportation system,the vibration characteristics of the flow transmission pipeline need to be analyzed.Based on the above requirements,this paper takes the cantilever flow straight pipe as the research object,establishes the dynamic control equations of the cantilever flow straight pipe under the action of flow excitation at macroscopic scale and microscopic scale respectively,adopts two methods of numerical simulation and simulation study to study the vibration characteristics of the cantilever flow straight pipe,and uses STAR-CCM+ engineering software to establish the finite element model of the cantilever flow straight pipe,and studies the flow-solid coupling vibration characteristics of the cantilever flow straight pipe under the influence of multiple factors.The details of the study are as follows:In Chapter 2,the equations of motion of a vertical cantilever flow transport pipe under flow excitation are established at the macroscopic scale based on the Euler-Bernoulli beam theory and the inextensibility condition using the generalized Hamilton’s principle.Then the Kelvin-Voigt internal energy dissipation model is introduced,followed by dimensionless discretization and finally modal discretization based on the Galerkin method,and a line shape analysis of the flow transport pipe is performed.The effects of different mass parameters,gravity parameters and dissipation effects on the stability of the system and the chattering rate are investigated.In Chapter 3,based on the basis of Chapter 2,the equations of motion of the transport nanotube at the microscopic scale are established based on the modified even stress theory and considering the viscoelasticity and scale effects of the flow transport pipeline.The relationship between dimensionless stiffness,dimensionless outer diameter,Poisson’s ratio and inner/outer diameter ratio of flow transfer pipes is analyzed.The effects of fluid velocity and scale effects on the system are also analyzed.In Chapter 4,a simplified finite element model is built using STAR-CCM+ engineering software,combined with finite element theory.The effects of pipe length,pipe wall thickness,and fluid velocity on the deformation of flow transfer pipes,pipe vibration displacement,and fluid pressure were studied.Finally,the flow-structure coupling vibration characteristics of horizontal and vertical cantilever flow pipes were compared.