Effects of Column Separation on Waterhammer in a Pipe

• Main Authors: Chiou, Yih-Leong, 邱翊倫
• Other Authors: Chii-Jau Tang
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/34331446190075536134

碩士 === 國立成功大學 === 水利及海洋工程學系 === 85 === The primary purpose of this study is to explore experimentally thephenomenon of liquid column separation which may occur within a pipewaterhammer propagation, and to explore further the causes of this phenomenonand its effects on the pipe transient. For different closure times of avalve, the shorter the duration ofthe valve,the easier the liquid column separation is to be found. Besides, the initial flow to be closed condition is oneimportant factor to have liquid column separation. A high initial flow rate causes the liquid column separated easily because of its great change in velocity; on the other hand, a high initial pressure is hard to form liquid column separation in the pipe. Liquid column separates as the liquid pressure in the pipe gets lower than its vaporizing pressure. This phenomenon slows down thepropagating velocity of waterhammer. The study employs the technique of spectrum and co- relation analyse to first present calculate the velocity of a waterhammer wave without the liquid column separation, and then to analyze the condition with it. Under the coupled influence of liquid and vapor, the propagation of waterhammer can''t get to a constant speed in a pipe. This difficulty makes the present study to perform qualitative discussion on the trend of velocityvariation and the celerity of waterhammer without liquid column separation. Finally, this thesis suggests the further study as well.