【作者】 金建峰；

【导师】 陈海波； 张培强；

【作者基本信息】 中国科学技术大学 ， 固体力学， 2009， 博士

【摘要】 上海同步辐射装置是一台高性能的第三代同步辐射光源,其电子储存环设计能量3.5Gev,仅次于日本的SPring-8、美国的APS和欧洲共同体的ESRF,居世界第四,是我国迄今为止最大的科学研究装置和公共实验平台。挡光元件是光束线前端区处理同步辐射高热负载、为其它元件提供热保护的关键元件。第三代同步具有极高的辐射功率和峰值功率密度,高热负载问题给SSRF前端区设计带来第一、二代光源尚未遇到一系列的困难。本文结合作者所在研究组承担的上海同步辐射装置前端高热负载研究项目,围绕前端挡光元件设计中的若干重要力学问题,开展冷却管道对流换热模拟、Glidcop材料热力学性能、前端挡光元件同步辐射循环热负载下疲劳寿命预测等方面的研究,为前端挡光元件的设计及优化提供重要参考。对流换热系数和流动阻力是前端挡光元件设计的重要参数,APS、SPring-8等第三代同步辐射装置为了提高管道对流换热系数进行了大量的实验研究。为了降低研究成本、节省研究时间,SSRF采用数值模拟和实验研究相结合的方法研究冷却管道的流体流动和对流换热问题。数值模拟结果表明SSRF弯曲管道的对流换热性能和冷却水流量基本满足前端冷却管道的设计指标;管道的流动阻力主要集中在直角弯曲区域,采用圆弧管道连接可以显著降低管道的流动阻力、提高管道的对流换热性能。为了验证传热数值模拟的正确性,根据牛顿冷却定律设计管道对流换热系数实验测量系统,对流换热系数的实验结果和数值模拟结果吻合良好,说明采用数值方法模拟管道流动和换热是正确可行的。第三代同步辐射产生的高热负载会在前端挡光元件表面产生极高的温度和热应力,前端区能否安全、有效发挥作用,与前端区各元件布局是否合理密切相关。本文利用有限元分析得到了各挡光元件在同步辐射热负载作用下的温度和应力场空间的分布,研究了束流漂移对前端挡光元件的最高温度和最大应力的影响。有限元分析结果表明,与前期的竖直倾斜面设计相比,采用水平倾斜面可以降低挡光元件的温度和应力水平,SSRF设计的前端挡光元件可以在300mA储存环流和漂移情况下安全运行。为了设计能够承受更高热负载的前端挡光元件,需要得到前端挡光元件的制造材料Glidcop在各种温度情况下的性能参数。本文通过文献调研,得到了Glidcop的比热、热传导系数、热膨胀系数等材料热物性随温度的变化关系。Glidcop的力学性能和材料的形状、尺寸以及热处理工艺相关,本文利用MTS材料测试系统对Glidcop在各种温度下拉伸性能进行了系统的实验研究,得到了材料在不同的温度下的应力应变关系。为了预测前端挡光元件在进入塑性变形后的疲劳寿命,利用MTS材料测试系统对Glidcop的各种温度下的低周疲劳性能进行了实验研究,建立了考虑温度影响的总应变-疲劳寿命关系。最后,利用弹塑性有限元方法对APS热疲劳元件在同步辐射循环加卸载下的温度和应力应变进行了详细分析,得到了疲劳元件在循环热负载作用下危险点的应力应变随时间的变化历程。采用多轴低周疲劳的临界面分析方法,分析了挡光元件可能的破坏面以及多种热负载作用下不同预测方法得到的疲劳寿命。研究表明采用基于临界面的多轴疲劳寿命分析方法能够对挡光元件在同步辐射热负载作用下的疲劳寿命进行可靠的预测。对SSRF挡光元件进行疲劳寿命分析表明,SSRF前端元件可以承受400mA束流条件下的同步辐射热负载循环卸载的作用。参照ASME压力容器设计标准,建立了考虑疲劳寿命的新的前端挡光元件设计准则。更多还原

【Abstract】 Shanghai Synchrotron Radiation Facility(SSRF) is a high performance third-generation of synchrotron radiation light source with an electron storage ring capacity of 3.5Gev,next only to SPring-8 of Japan,APS of USA and ESRF of the European Community.Up to now,SSRF is the biggest scientific platform for science research and technology development in China.The high heat load components on the front end are key components for dealing the high heat load of synchrotron radiation, as well as providing thermal protection to other components.The high heat load problems,resulting from the extremely high radiation power and peak power density in the third generation synchrotron radiation,bring new challenges to the design of SSRF front end that were never encountered in the previous two generations.This dissertation is a part of two research projects on the high heat load of the front end we are working for SSRF,it focuses on some major mechanics issues of the high heat load components in the front end,which includes heat transfer coefficient simulation on coolant tube,decreasing heat flux with grazing incidence structure,and establishing new design criteria for high heat load components.The heat transfer coefficient and flow resistance characteristics of forced convection in coolant tube are critical parameters to the design of front end components,because they influence significantly on the temperature and thermal stress distribution there.Much experimental investigation for enhancing heat transfer coefficient has been carried out at APS and SPring-8.In order to reduce study cost and time,numerical simulation is employed to assist the study on fluid flow and heat transfer in the coolant tube at SSRF,whose results show that the heat transfer coefficient and coolant water flow capacity can meet the SSRF design criteria,and the flow resistance mainly comes from the orthogonal region.The use of circular connecting tube can significantly reduce the flow resistance and increase the heat transfer coefficient of the coolant tube.In order to verify the results of the numerical simulation,an experimental system that can measure heat transfer coefficient of the tube is designed.The experimental results are in good agreement with numerical results,which implies that the use of numerical simulation of tube heat transfer is correct and feasible.The high heat load generated by the third-generation synchrotron radiation device will result in extremely high temperature and thermal stress on the surface of the high heat load components in the front end.The safety and effectiveness of the front end are influenced greatly by its components layout.While studying the temperature and stress field distributions of the synchrotron radiation heat load components,the finite element method(FEM) is used to analyze the influence of beam shift on the highest temperature and maximum stress.FEM results showed that, compared with the preliminary design of vertical grazing incidence,the horizontal grazing incidence design could reduce obviously the temperature and stress level,and the front end component in the current design of SSRF can run safely under a beam current of 300mA.In order to design components that can withstand higher heat load,we need to learn the mechanical parameters under various temperatures of the material of the front end components,Glidcop.The temperature dependent variations of several thermal properties of this material,e.g.,heat capacity,heat conduction coefficient and thermal expansion coefficient are obtained through literature study,which reveals that the mechanical properties of Glidcop is related with its shape,size and thermal treatment process,though there is so few literature reports on the stress-strain relationship under high temperature and low cycle fatigue of this material.A material testing system,MTS is employed in this research to carry out systematic study on the tensile properties of Glidcop under various temperatures,and the relationship between the overall strain and fatigue life with temperature influences is established.Detailed analysis on the temperature and stress-strain distributions were carried out with elastic-plastic finite element method in this thesis for the thermal-fatigue components used at APS under cycled load-unload synchrotron radiation and the components’ temporal evolution of stress and strain was obtained.Besides,the possible destruction surface and fatigue life of the high heat load components under multiple heat loads are predicted with multi-axial low cycle fatigue(LCF) critical plane analysis.The fatigue life analysis on the SSRF high heat load components indicates that these components can be safely subjected to the cycle heat load of the synchrotron radiation under 400mA beam current.By referencing to the ASME design standards of pressure vessels,a new design criteria based on LCF life was established for the front end components.更多还原