变温热源布雷顿循环的功率密度优化

POWER DENSITY OPTIMIZATION OF A BRAYTON CYCLE WITH VARIABLE-TEMPERATURE HEAT RESERVOIRS

计入工质与高、低温侧换热器的热阻损失及压气机和涡轮机中的不可逆压缩和膨胀损失，用有限时间热力学方法，导出了恒温热源条件下不可逆布雷顿循环功率密度与压比间的解析式，借助于数值计算，研究了高、低温侧换热器的热导率分配和工质与热源间的热容率匹配对最大功率密度的影响。

The analytical formulas about the relations between power density and pressure ratio of an irreversible Brayton cycle coupled to variable-temperature heat reservoirs are derived using finite-time thermodynamics. In the analysis, the irreversibilities involve the heat resistance losses in the hot- and cold-side heat exchangers, and the irreversible compression and expansion losses in the compressor and turbine. The influences of the thermal conductance distribution of the hot- and cold-side heat exchangers and the thermal capacity rate match between the working fluid and the heat reservoirs on the maximum power density are studied by numerical examples.