Heat Exchangers System Design Powered by Supercritical H2O

• Main Authors: Sin-Wei Kao, 高昕暐
• Other Authors: Shih-Pin Liaw
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/28377015894723613091

碩士 === 國立臺灣海洋大學 === 機械與機電工程學系 === 98 === Abstract The purpose of this thesis is the demarcation between supercritical and subcritical water is based on the critical point of water at 374℃ and 22MPa. While the critical point is accessed, the coexistence of liquid and vapor phases accompanied with high pressure and temperature which results in a higher thermal efficiency state. However, the strength of the structural material should be addressed. As to the strength calculation, the CNS standard was followed. The allowable stresses of SUS316L and Inconel-718 used in the heat exchangers design are found and thus the minimum thickness of pipe can be obtained. LMTD method is used to analyze the required heat transfer area, and the overall length of the heat exchanger is estimated. A computer code written in Excel is developed to handle this problem. By varying the input parameters, an optimal design is recommended. In the thermal analysis, the fouling factors have been ignored due to the usage of distilled water. The summation of the remaining three-term resistance Ri, Rwall and Ro is to be minimized and a higher heat transfer rate is achieved. Key word: Double pipe, supercritical, pressure vessel, fin