弯曲残余应力对转子蠕变性能的影响研究

Research on Rotor Creep Properties under Bending Residual Stress

针对某600 MW火力发电机组高中压合缸汽轮机转子的中部弯曲进行分析,认为高温蠕变和残余应力的耦合作用是导致转子发生塑性永久变形的主要原因。首先按照转子结构图利用有限元软件ANSYS建立精细化的三维实体模型,并进行温度场和应力场的有限元分析。在此基础上对高中压转子进行热-固耦合分析,通过对转子材料蠕变试验数据进行处理,得到Norton蠕变模型参数,并在ANSYS中对转子的高温蠕变和残余应力进行有限元仿真。研究表明,单纯的高温蠕变不足以引起转子在启动过程中发生弯曲,耦合残余应力的作用后该高中压转子会在很短时间内发生弯曲值超标,选取Norton三参数模型和残余应力生成方法比较有效。该研究对高中压合缸转子中部弯曲原因分析具有借鉴和指导作用。

Central bending analysis of a 600 MW thermal power generating unit’s HP-IP combined casing rotor is conducted and it concludes that high temperature creep and residual stress is the main reason leading to permanent plastic deformation. First, they build the fine three-dimensional solid model with the FEA software ANSYS according to the rotor structure. It carries out finite element analysis of temperature field and stress field. On this basis, heat-solid coupling analysis is proceed, by dealing with the experiment data, they get the parameters of Norton creep model and implement finite element analysis of high temperature creep and residual stress in ANSYS. The research show that simply high temperature creep is not sufficient to cause the rotor bending during start-up process, but rotor bending will happen in short time if coupled with the residual stress. Using Norton three-parameter model and generating residual stress method are proved more effectively. The conclusion drawn can be referenced and guided for analysing the HP-IP combined casing rotor’s central bending.