中文摘要：

基于现有燃气轮机机组,对于给定透平初温,重新划分顶循环与底循环的能量利用区间与比例,分析与三种常见底循环参数相匹配的燃气–蒸汽联合循环全工况性能。以PG9351FA燃气轮机为顶循环的联合循环机组作为基准机组,研究了3个案例机组的全工况性能（PG9351FA燃气轮机匹配底循环初参数为567.5℃;压气机设计压比提高为18匹配底循环初参数为538℃机组;压气机设计压比降低为12.73匹配底循环初参数为603℃机组）。研究结果表明：提高压气机设计压比,其全工况性能优于基准机组,并且具有良好的变工况性能,效率比基准机组提高幅度为0.03%~0.42%,然而其出功降低幅度为1.66%~2.72%;降低压气机设计压比,其全工况性能劣于基准机组,效率降低幅度为0.20%~0.39%,然而其出功增加,增加幅度为1.19%~3.27%。通过对顶循环与底循环的？分析发现联合循环整体性能的主要取决于顶循环,提高顶循环的热力学完善程度更有利于提高联合循环的全工况性能,对于底循环无需追求高参数;并且对于同一燃气透平入口温度,如果设计工况下联合效率较高则在全工况条件下效率也较高。因此,对于追出功的地区可以按照最佳比功来选择设计压比,然而对常参与调峰的机组可以选择压气机设计压比较高的机组。并且对于同一燃气透平入口温度,如果设计工况下联合循环效率较高则在全工况条件下效率也较高。因此,对于追求大出功的地区可以按照最佳比功来选择设计压比,然而对于经常参与调峰的机组可以选择压气机设计压比较高的机组。

英文摘要：

Based on parameters of the existing gas turbine units, the energy utilization interval for topping and bottoming cycles was repartitioned with the given turbine initial temperature, and the design/off-design performance of the combined cycle matched with three common bottoming cycle parameters was analyzed. The combined cycle with PG9351 FA gas turbine was selected to be the benchmark unit, and the performances of three typical units were studied（1. Gas turbine PG9351 FA with the bottoming cycle of main steam temperature of 567.5℃; 2. Increasing the design pressure ratio of compressor to 18 to match the bottoming cycle with main steam temperature of 538℃; 3. Reducing the design pressure ratio of compressor to 12.73 to match the bottoming cycle with main steam temperature of 603℃）. The results show that, with higher design pressure ratio the unit exhibits a better off-design performance compared with the benchmark unit, with the efficiency increment of 0.03%~0.42%, but its net power output will decrease by 1.66%~2.72%. On the contrary, the unit with lower design pressure ratio has lower off-design performance with the efficiency decrement of 0.20%~0.39%, but its net power output will increase by 1.19%~3.27%. By the exergy analysis of topping and bottoming cycles, it can be found that the off-design performance of combined cycle mainly depends on the topping cycle. Improving the thermodynamic perfectiondegree of the topping cycle can enhance the design/off-design performance of a combined cycle, rather than pursuing higher parameters of the bottom cycle. At a given turbine initial temperature, the efficiency of a combined cycle will be higher at whole working condition if its performance is higher at the design condition. Thus, it can be concluded that a gas turbine combined cycle with the maximum specific work is suitable for the district with large power demand, while a combined cycle with relative higher pressure ratio is suitable for frequent peak shaving.