两级中冷回热再热布雷顿热电联产装置的性能

应用有限时间热力学理论和方法建立了恒温热源不可逆两级中冷回热再热布雷顿热电联产装置模型,基于分析的观点,导出了装置无量纲输出率和效率的解析式。在给定总压比的情形下,通过数值计算分别研究了输出率和效率与两个中冷压比和两个再热压比的关系,当总压比变化时,发现输出率和效率对总压比存在最大值,并分别求出了两个相应的最佳的中冷压比和再热压比。分析了回热度、中冷度、再热度、压气机和涡轮机效率、压降损失等特征参数对装置性能的影响。最后发现分别存在最佳的用户侧温度使输出率和效率取得双重最大值。

Exergy Performance of a Two-Stage Intercooled Regenerated Reheated Brayton Combined Heat and Power Plant

An irreversible two-stage intercooled regenerated reheated Brayton combined heat and power plant model coupled to constant-temperature heat reservoirs is established using finite time thermodynamics.From the perspective of exergetic analysis.the analytical formulae about dimensionless exergy output rate and exergy efficiency of the plant are deduced.In the case of fixed total pressure ratio,the relations of exergy output rate and exergy efficiency with respect to the two intercooling pressure ratios and the two reheating pressure ratios arc studied by means of numerical calculations.When the total pressure ratio is variable,it is found that exergy output rate and exergy efficiency exist maximum values with respect to the total pressure ratio,meanwhile the two corresponding optimal intercooling pressure ratios and reheating pressure ratios are obtained, respectively.The effects of characteristic parameters included degrees of regeneration,intercooling and reheating,the efficiencies of the compressors and turbines,and the pressure drop losses on the exergetic performances of the plant are analyzed.Finally,it is found that there exists two optimal consumer-side temperatures which lead to a double maximum dimensionless exergy output rate and a double maximum exergy efficiency,respectively.