间冷过程对三级回热压缩S-CO_(2)循环系统的影响

Effect of Intercooling Process on Three-stage Regenerative-compression S-CO_(2) Cycle System

三级回热压缩循环效率高、结构简单,是一种比再压缩循环更具潜力的超临界二氧化碳循环。间冷过程是一种常用的提高布雷顿循环效率的方法,当应用该方法时,可进一步提高循环效率。本文研究了三级回热压缩循环与间冷过程耦合时的特性,计算发现,当间冷压力偏离最优值时,循环效率会有明显下降,甚至低于同参数无间冷循环的效率。而在最优间冷压力下,间冷级数越高,对应的循环效率就越高,但效率增幅会逐渐降低。与再压缩循环相比,间冷过程与三级回热压缩循环耦合时效果更好,其效率优势能达到1%以上。当透平进口温度提高时,间冷过程对循环的效率增益会被削减。而当透平进口压力提高时,存在一个最优透平进口压力使循环效率最高,且随间冷级数增加,最优透平进口压力也会提高。

The three-stage regenerative-compression cycle(TC)has high efficiency and simple structure.It is a more potential supercritical carbon dioxide(S-CO2)cycle than recompression cycle(RC).Intercooling process is a common method to improve the efficiency of Brayton cycle.When this method is applied,the cycle efficiency can be further improved.In this paper,the characteristics of TC coupled with intercooling process are studied.It is found that when the intercooling pressure deviates from the optimal value,the cycle efficiency will decrease significantly,even lower than that of the cycle without intercooling.Under the optimal intercooling pressure,the higher the intercooling stage,the higher the cycle efficiency,but the efficiency increase will gradually decrease.Compared with the RC,the coupling effect of the intercooling process and the TC is better,and its efficiency advantage can reach more than 1%.When the turbine inlet temperature increases,the efficiency gain of the intercooling process will be reduced.When the turbine inlet pressure increases,there is an optimal turbine inlet pressure to make the cycle efficiency highest,and with the increase of intercooling stage,the optimal turbine inlet pressure will also increase.