基于流固耦合的热电偶套筒瞬态动力学分析

Transient dynamic analysis of thermocouple sleeves based on fluid-solid coupling

热电偶是电厂中最常用的蒸汽温度测量装置,而在使用过程中热电偶的保护套筒会发生断裂、折断等事故.针对此现象,以电厂过热器连接管中的热电偶套筒为研究对象,在建立其几何模型的基础上,采用结构化六面体网格对模型进行划分,采用结构化四面体网格对流体模型进行划分,得到流-固载荷传递模型.利用ANSYS Workbench有限元分析软件进行流固耦合计算,在Fluid Flow（Fluent）模块下进行最大流速下流场瞬态计算,利用流场计算结果作为结构计算的压力载荷输入,在Transient Structural Analysis模块下进行热电偶套筒结构瞬态动力学分析,得出其等效应力、变形量和应变能的计算结果,从而评估热电偶套筒结构的安全性.

Thermocouple is the most commonly used steam temperature measuring device in power plants;but the thermocouple sleeve may break during use.In view of this phenomenon,this paper takes the thermocouple sleeve in the superheater connecting tube of the power plant as the research object.Based on the establishment of its geometric model,the model is divided by a structured hexahedral mesh.Meanwhile,the fluid model is divided by using a structured tetrahedral mesh,the flow-solid load transfer model is presented.In addition,ANSYS Workbench finite element analysis software is used to fluid-solid coupling analysis.The flow field calculation is carried out under the Fluid Flow（Fluent）module under the maximum flow rate.The flow field calculation results are used as the pressure load input of the structure calculation.Transient dynamic analysis of the thermocouple sleeve structure is carried out under the Transient Structural Analysis module;the equivalent stress,deformation and strain energy calculation results are obtained to evaluate the safety of the structure.