An Investigation on Dynamic Characteristics of A Hollow Tube

• Main Authors: Lin, Yang-Chen, 林揚程
• Other Authors: Kung, Huang-Kuang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/55876528776265721412

碩士 === 正修科技大學 === 機電工程研究所 === 101 === In a nuclear power plant, the tubes of a component cooling water heat exchanger are frequently affected by cold and hot fluid shock waves. Thus, tubes are often found to be worn out. This wear may alter the dynamics characteristics of the tubes and introduce mode localization in the heat exchanger. This paper examines mode localization in a component cooling water heat exchanger. A heat exchanger, consisting of periodic cooling tubes is used to simulate as a coupled periodic structure system. Each tube is coupled to the adjacent one through the water, and so the system is weakly coupled. The Galerkin method is employed herein to derive equation of motion of the hollow tube system, without reference to the fluid effect. The numerical methods are used for solving the natural frequency of the system. The finite element analysis software ANSYS is also adopted to build the geometric model of a hollow tube and solved for modal dynamic characteristics, including the normal mode analysis and time displacement response, etc. Thirty natural frequencies and mode shapes are obtained for this hollow tube. Numerical results reveal that the results of the analyzed model of the hollow tube are in the acceptable range. The natural frequencies and mode shapes can be referred for future design or improve the tubing system and components of the heat exchangers.