Supercritical CO2 Brayton Cycle Compressor Blade Design and Analysis

• Main Authors: Liu, Kai-Wen, 劉凱文
• Other Authors: Chiang, Hsiao-Wei
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/ma3872

碩士 === 國立清華大學 === 動力機械工程學系 === 105 === Accompanied by the prosperity of technology, the electricity needed for production is increasing year to year. However, the overall efficiency is not above 50%, and thus it will produce large amount of carbon dioxide and waste heat. It will give rise to the global warming aggravation and the air pollution, sour rain, ozonosphere holes and the destruction of forest…etc. So this paper intend to find an solution to finding alternative energy and recovery of waste heat, with the increasing literatures focusing on the super critical cycle in the energy recovery field. This paper put aim on the super critical Brayton cycle to make the first compressor design. According to the Sandia Laboratory’ reports, the overall efficiency of the combined cycle can be high above 50%. The reason to use carbon dioxide to be the working fluid is due to its stability, low critical condition, large range of application and capable of reducing the global warming. This paper design the prototype of the blades and rotors of the compressor. And then, by using ANSYS this paper propose a layout of the rotor and blade which can bear high temperature and pressure(7.8~15 MPa, 300~500K). And this model has been verified by comparing the simulation results with the paper [35]. The results are quite similar where the errors are below 6%. The efficiency of the impeller is about 50.1%, compared with the 25% efficiency of the impeller by using Air Ideal Gas as working fluid. It has been proven that the SCO2 compressor impeller is the best choice over the conventional Rankine cycle and the Brayton cycle by Air Ideal Gas. With the advantages of high rotating speed and the low volume, the pressure ratio of this compressor is about 1.85; the efficiency is about 50%.