Numerical Research On Fretting Wear Of Heat Transfer Tube Of Nuclear Steam Generator

The heat transfer tube in nuclear steam generators is a key component of nuclear power equipment.The existence of fluidic vibration in the tube causes various forms of fretting wear at the connection between the heat transfer tube and the support plate,which can lead to local thinning or even rupture of the heat transfer tube due to wear over time.Thus,it will greatly endanger the safe operation of nuclear power plants.However,due to the complexity of the nuclear heat transfer tube service environment,the influence mechanism of the fretting wear evolution process has not been fully revealed.Considering the fretting wear of heat transfer tube of nuclear power generator as the main object in the present paper,then tangential wear models,punch-slip wear models and thermodynamic coupling models of nuclear heat transfer tube are established,aiming to analyze tangential fretting wear,thrust-slip fretting wear and thermal effects in the friction process of the nuclear heat transfer tube through numerical simulation.The effects of normal load,fretting amplitude,fretting cycle period and service conditions on wear profile,wear volume,friction stress,friction dissipation energy and frictional heat generation during the wear process are investigated.This study can provide theoretical reference for reducing the fretting wear of nuclear heat transfer tubes,which is of practical significance for improving the reliability of nuclear heat transfer tube components and ensuring the safe operation of nuclear reactors.Specific research results are as follows:1.The numerical model of nuclear heat transfer tube fretting wear was constructed,with the Umeshmotion subroutine being compiled,and the energy wear finite element method based on ALE adaptive was introduced to realize the wear evolution process.Therefore,the mechanical mechanism of nuclear heat transfer tube fretting wear was analyzed.By comparing the finite element results with the experimental results,the reasonableness and accuracy of the wear model for the nuclear heat transfer tube were verified.2.The finite element model of tangential fretting wear of nuclear heat transfer tube was established,and the tangential fretting wear behavior of nuclear heat transfer tube was studied numerically.To be specific,the evolution of wear under different fretting operating conditions and the stress change of initial contact surface were simulated,and the effects of normal load and fretting amplitude on the evolution of wear profile,stress distribution,relative slip distance,wear volume,frictional dissipation energy,and contact area of contact surface were presented through a series of graphical results.Moreover,the mechanical response of tangential fretting wear of the nuclear heat transfer tube under different service conditions was discussed.3.The finite element model of nuclear heat transfer tube punch-slip fretting wear was established,and effects of the normal impact load and the tangential fretting amplitude on the evolution of wear profile,frictional dissipation energy,and wear volume of the contact surface were investigated by introducing the Dload subroutine that could apply impact load.4.The numerical study of the frictional heat generation during the fretting wear of nuclear heat transfer tubes was carried out,and the temperature rise distribution of the contact surface under high cycle number was investigated using Fric subroutine.Then the thermodynamic behavior of fretting wear of nuclear heat transfer tubes was investigated.Hence,the influence of the temperature rise on the mechanical mechanism of fretting wear was explained.