超级质子-质子对撞机中束流热屏的热-结构耦合模拟分析

Thermal-structural coupling analysis of beam screen in super proton-proton collider

束流热屏(beam screen)是新一代高能粒子对撞机中的重要部件,用于将束流在管道中运行时产生的热量转移到冷却系统中,同时通过束流热屏上的排气孔将残余气体输送至冷管壁上,维持良好的真空度.然而,在转移热负载的过程中,温度变化产生的形变会影响束流热屏的结构稳定性.如何在保证束流热屏良好传热性能的情况下,尽量减小形变是优化束流热屏结构设计的关键问题之一.本文采用ANSYS软件对束流热屏模型的传热性能和力学性能进行了模拟,并优化了束流热屏结构设计,增强其传热性能和结构稳定性.对于束流热屏外屏的内表面,采用减小铜涂层厚度的方式来降低运行过程中产生的洛伦兹力.相关理论模型计算结果表明:与厚度为100μm的铜涂层工况相比,当铜涂层的厚度在0到100μm之间变化时,厚度为75μm的铜涂层可以使束流热屏外屏的最大形变降低70.9%,同时使束流热屏的最高温度升高1.1%.对于束流热屏内屏,采用间隔布置支撑肋片的设计方案对束流热屏的结构进行加固处理,提高束流热屏整体的结构稳定性.计算结果表明:与未加支撑肋片的工况相比,当相邻两个支撑肋片之间的间隔为1个排气孔时,束流热屏内屏的最大形变可降低86.8%,同时使束流热屏的最高温度降低7.69%.研究成果为新一代高能粒子加速器真空系统中关键部件束流热屏的设计提供重要的理论参考.

High-energy colliders play an indispensable role in particle physics and high-energy physics.Beam screen is one of the key parts in the high-energy collider.It is used to transfer the heat generated by the beam in the pipeline to a cooling system,and absorb the residual gas to the cold bore through the pumping holes on the wall of the beam screen to ensure the vacuum stability at the same time.However,in the process of transferring thermal load,the deformation caused by temperature change will affect the structural stability of the beam screen.How to reduce the deformation as much as possible while ensuring the good heat transfer performance of the beam screen is one of the key issues in optimizing the structural design of the beam screen.In this paper,the heat transfer performance and mechanical property of the beam screen model are simulated and optimized based on the ANSYS simulation results to ensure the normal and stable operation of the beam in the super proton-proton collider.For the inner surface of the outer screen of the beam screen,the method of reducing the thickness of the copper coating is used to reduce the Lorentz force generated during operation.The calculation results from the relevant theoretical models show that when the thickness of the copper coating varies from 0 to 100μm,the copper coating with a thickness of 75μm can reduce the maximum deformation of the outer screen of the beam screen by 70.9%,while the maximum temperature of the beam screen can be increased by 1.1%.For the inner screen of the beam screen,a design scheme in which supporting ribs are arranged at intervals is used to reinforce the structure and improve the overall structural stability of the beam screen.The calculation results show that the maximum deformation of the inner screen of the beam screen can be reduced by 86.8%and the maximum temperature of the beam screen is reduced by 7.69%,compared with the case without supporting fins,when the interval between two adjacent supporting fins is 1 pumping hole.The research results provide important theoretical reference for the design of beam screen,which is the key component of the vacuum system of the new-generation high energy particle accelerator.