| Summary: | 博士 === 正修科技大學 === 機電工程研究所 === 103 === Effect of fluid on the dynamics and stability of a coupling periodic system are investigated in this thesis. The coupling fluid systems, such as the heat exchanger, are frequently employed to depress the heat in the industry. This heat exchange system is applied in a very wide range of industrial machinery and is a device which cannot be lacked. From the general consumer goods such as water heaters to the large nuclear power plants in the heat exchange system, the heat exchanger is necessary. Especially in the nuclear power plant, the heat exchange system is the main safety equipment in the main equipment to cool the high heat if the nuclear incidents occur. But the high cycling operating cold and hot conditions, a lot of hot and cold water shock often leads to heat exchanger tubes wear, and then lead to severe vibration and leakage. This phenomenon often occurs in nuclear power plants. This result leads to a significant risk of nuclear safety. In an actual industry application, because of the tubes in the heat exchanger by a thermal shock is worn or damaged, it will lead to increased vibration of the entire system and damage to the system.
Therefore, the dynamic characteristic and instability of a component cooling water heat exchanger is considered in this thesis. Due to the fluid coupling effect, the heat exchanger with all tubes assembled periodically, so called a periodic system, can be simulated as the tubes with fluid. In this coupling periodic system, the periodically coupled tubes with fluid flow can be employed to simulate a heat exchanger system. The tube simulated as a round hollow Euler-Bernoulli beam in this work. By using the Galerkin method, the discrete equation of this periodic coupling system can be derived. Numerical results are observed that the fluid flow may affect significantly the dynamics and instability of a component cooling heat exchanger. This thesis intends to explore for this phenomenon, hoping this industry issues to be analyzed and discussed in advance and then put forward to improve the prevention mechanism.
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