THE DYNAMIC CHARACTERISTICS OF COAXIAL CYLINDRIAL SHELL CONVEYING FLUID

With Nuclear Power Plant (NPP) reactor core barrel as engineering background, this paper studies the dynamic characteristics of coaxial cylindrical shell conveying fluid. Based on Flugge shell theory and the potential theory in fluid mechanics, this paper obtains the equation which describes the dynamic characteristics of coaxial cylindrical shell system. The model of the Qinshan NPP phase II 1:5 model test is used as an illustration to verify the developed equation. The natural frequencies of the structure are obtained by solving the frequency equation. This paper discusses the factors influencing this system’s dynamic characteristics, such as the fluid velocity fluid density and the ratio of thickness versus diameter of structure. Among all these factors the influence of fluid velocity is less than others. So the natural frequency in still water can be used in the case of moving water.