Study on the Sealing Performance of Pipe Flange Connections at Elevated Temperature by Computational Mechanics

1.考虑接触热阻的温度场数值分析方法将接触热阻的经验公式与热行为和结构分析的商用程序相结合，建立了高精度的三维温度场数值分析方法.螺栓连接周围热流模式及螺栓预紧力变化机理的解析利用上述方法，全面解析了螺栓连接周围的热流和螺栓轴向力的变化规律.热载荷作用下管法兰连接的温度场和应力场分析采用精确几何形状的管法兰模型，分析了管法兰的温度场和应力场，并计算了管法兰热变形引起的螺栓轴向力的变化.垫片高温压缩试验设备的研制一种能产生30MPa的压缩压力，使垫片温度升高300 ℃的压缩试验设备。开发了在从室温到150 ℃的各种温度下获得了片状垫片的压缩曲线。高温下垫片材料性能对密封性能的影响利用所得到的压缩曲线，研究了高温下垫片刚度变化对密封性能的影响.为了建立高温下管道法兰连接的紧固操作准则，建立了一种数值计算方法，为分析高温下管道法兰连接的热力学行为提供了坚实的基础

1. Numerical Procedure for Temperature Analysis by Taking Account of Thermal Contact resistance A three-dimensional numerical procedure with high accuracy for temperature analysis has been established by incorporating the empirical equation for thermal contact resistance into a commercial program which can deal with thermal behavior and structural analysis.2. Elucidations of the Heat Flow Pattern around Bolted Joint and the Mechanism of Bolt Preload Variation It has been comprehensively elucidated using the above method how the supplied heal flows around the bolted joint and the magnitude of axial bolt force varies.3. Temperature and Stress Analysis of Pipe Flange Connections subjected to Thermal Load Using pipe flange models with accurate geometry, its temperature and stress fields were analyzed, and the variations of axial bolt force due to the thermal deformation of pipe flange have been evaluated.4. Development of Compression Test Equipment for Sheet Gaskets at Elevated Temperature A compression test equipment which can generate the compressive pressure up to30MPa and increase the gasket temperature as high as 300 deg. has been developed. Compression curves of sheet gaskets were obtained at various temperatures from room temperature to 150 deg.5. Effects of Material Properties of Gaskets at Elevated Temperature on the Sealing Performance Using the compression curves so obtained, it has been investigated how the stiffness variation of gaskets at elevated temperature affects the tightening characteristics.6. Guideline for the Tightening Operation of Pipe Flange Connections at Elevated Temperature In order to establish a guideline for the tightening operation of pipe flange connections at elevated temperature, a numerical procedure, which provides a rigid foundation to analyze thermal and mechanical behaviors of pipe flange connections, has been established