再热Brayton循环效率特性分析

Analysis of the Efficiency Characteristics of the Brayton Reheat Cycle

在燃气轮机循环中工质温度变化范围大,其比热是变化的。利用数值分析方法研究了工质变比热情况下再热Brayton循环的效率特性,发现存在最佳循环总效率和对应的最优压比,讨论了循环温比、压气机和透平效率对循环最优压比和循环总效率最佳值的影响,比较了压气机效率和透平效率的影响程度,并指出了已有文献的错误。所得的分析结果对燃气轮机的优化设计和运行参数选择具有一定的指导作用。

In a gas turbine cycle,the working medium temperatue varies in a wide range and its specific heat also changes.By utilizing a numerical analytic method,studied were the efficiency characteristics of the Brayton reheat cycle under the condition of the specific heat of the working medium being changed.It has been found that there exist an optimum total efficiency of the device and its corresponding optimum pressure ratio.The influence of the temperature ratio of the cycle and the efficiency of the compressor and turbine on the optimal pressure ratio of the cycle and the optimal total efficiency of the device was also investigated.On this basis,the influencing extents on the efficiency of the compressor and turbine were compared and the mistakes existing in the currently available literatures were pointed out.The foregoing can offer certain guide for optimized design and selection of operating parameters of a gas turbine.