Avoiding sealing failure of flanged connection for tubes made of dissimilar materials subjected to elevated temperature

作     者：Qi-Ming Li Chong Zhou Jian Tian Yao Fu Yang Zou Na-Xiu Wang 

作者机构：Shanghai Institute of Applied Physics Chinese Academy of Sciences 

出 版 物：《Nuclear Science and Techniques》 (核技术（英文）)

年 卷 期：2019年第30卷第1期

页      面：107-112页

核心收录：

学科分类：08[工学] 0807[工学-动力工程及工程热物理] 0827[工学-核科学与技术] 0703[理学-化学] 0702[理学-物理学] 0801[工学-力学（可授工学、理学学位）] 

基　　金：supported by the Chinese TMSR Strategic Pioneer Science and Technology Project(No.XDA02010000) the Frontier Science Key Program of Chinese Academy of Sciences(No.QYZDY-SSW-JSC016) 

主　　题：Sealing Composite flanged connections Thermal expansion Mechanical analysis Molten salt reactors 

摘      要：Carbonic composite materials and ceramics appear to be excellent structural materials for parts subjected to very high temperatures in molten salt reactors(MSRs), in which the reactor core outlet temperature is normally above 700℃. Because of the high temperature,there are major challenges in the sealing of flanged connections for tubes made of alloys and nonmetallic materials. In this study, an improved method for sealing bolted flange connections for tubes made of dissimilar materials at high temperature is analyzed. The study focuses on the compensation mechanism for the difference in thermal expansion between the bolts and the flanges. An angle is introduced for the sealing surface in the flanged connection to provide effective sealing. The arctangent of the angle is the ratio of the thickness between the theoretical core of the sealing surface and the outside end face of the flange to the distances between the axis of the flanged joint and the theoretical core of the sealing surface of the flange; the sealing surface of the flange, which is made of the same material as the fastening assemblies, faces the fastening assemblies. To ensure effective sealing, the frictional coefficient between the two sealing surfaces should not exceed the tangent of the angle. This result does not agree well with the solution given by previous researchers. Further, in the modified flanged connection, the compression of each bolt in the clamped condition is increased to maintain the compaction force unchanged without increasing the number of bolts on the flanged joint.