Dynamic Analysis of a Closed Brayton Cycle Using Supercritical Carbon Dioxide

Abstract

It is important to study the dynamic characteristics of closed Brayton cycle using supercritical carbon dioxide(S-CO2) for the research of the automatic control method of the system operation. The dynamics characteristics of a split-flow recompression closed Brayton power conversion system with supercritical carbon-dioxide as the working-fluid was investigated. The mathematics model about the compressor, turbine, recuperator in a S-CO2 Brayton cycle system was studied on the basis of the conservation principle and the basic equations of engineering thermodynamics, heat transfer theory and hydrodynamics. A complete system dynamic simulation model was built to study the dynamic response characteristics of the system under different disturbances by using the programming language in the computer. The results show that: the heating power of the heater is increased by 15.4%, the operating parameters are improved, the cycle efficiency is increased by 7.8%, the power of the pre-cooler is reduced by 50%, the cycle efficiency is reduced by 1.8%, and the opening of the valve is reduced by 10%, and the cycle efficiency is improved.