基于精细螺栓模型的爆破阀热固耦合密封性能分析

Sealing Performance Analysis of Blasting Valve Based on Fine Bolt Model by Thermomechanical Coupling

爆破阀是新一代核电机组的关键防护装置,正常运行时,要求阀门本体零泄漏,其密封性主要取决于热和工作载荷作用下的螺栓接头的力学性能。针对以往螺栓连接件分析中没有考虑螺纹细节的情况,建立了可以准确描述螺纹细节的精细化有限元模型;考虑了垫片非线性行为,垫片采用ABAQUS软件中的GASKET单元;对爆破阀温度场和应力场、螺栓拉伸力进行分析。发现了螺栓拉伸力最低的时刻,并评价此时垫片的密封性能。对不同螺栓预紧力下以及不同载荷下螺栓拉伸力变化情况进行了研究;对螺纹接触面状态变化与螺栓拉伸力关系、各螺距螺纹所占螺栓拉伸力比例、螺母转角与螺栓拉伸力关系进行分析;对过盈模型、Bolt Load模型、考虑螺纹装配的精细模型三种不同施加预紧力的模型分别进行模拟比较,得出精细模型能更真实地模拟螺栓拉伸力的变化过程。

Blasting valve is the key protection device of the new generation of nuclear power units. During normal operation, the valve body requires zero leakage. The sealing performance mainly depends on the mechanical properties of the bolted joints under the action of heat and working load. Aiming at the prob- lem that the screw details were not considered in the analysis of the bolted joints in the past, a detailed fi- nite element model was established to accurately describe the thread details. Considering the gasket non- linear behavior, the gasket adopts the GASKET unit in the ABAQUS software. Temperature field and stress field, bolt tensile force were analyzed. The lowest moment of bolt tensile force is found, and the gasket sealing performance is evaluated. The bolt tensile force under different bolt preload and different load was studied. The relationship between the change of thread contact surface and bolt tensile force, the ratio of tensile force of bolt by each thread pitch, the relationship between the nut rotation angle and bolt tensile force were analyzed. 3＂he models of the interference model, the Bolt Load model and the fine model of the thread assembly are compared and simulated respectively. The results show that the fine model can simu- late the change of the tensile force of the bolt more realistically