超临界二氧化碳闭式循环性能仿真研究及应用

Study and application of performance simulation of supercritical CO2 closed cycles

为了研究超临界二氧化碳闭式循环动力系统的稳态性能,本文通过整合压缩机、透平、换热器、管道等动力系统主要部件的数学模型,形成各部件共同工作需要满足的非线性方程组,发展出了超临界二氧化碳闭式循环系统级模型。采用建立的系统级模型对比分析了10 MW等级简单循环和再压缩循环系统在设计状态和非设计状态的性能。结果表明:在设计状态下,再压缩循环的热效率高于简单循环;在非设计状态下,如果不优化分流比,再压缩循环的性能下降速率更快。

To investigate the steady state performance of supercritical carbon dioxide closed cycle, by integrating the mathematical models of major components in power system such as compressor, turbine and heat exchanger into a nonlinear equation group that each component need when works together, a system-level model which is capable of predicting the design-point and off-design operation of supercritical carbon dioxide closed cycles was developed. Moreover, the system-level model was used to compare the performance of 10 MW-level simple cycle and recompression cycle under design and off-design conditions. The result indicates that the recompression cycle shows a better performance under design conditions, but its performance drops faster if the split ratio is not optimized under off-design conditions.