燃气轮机回热循环新析

NEW ANALYSIS OF RECUPERATIVE GAS TURBINE CYCLES

本文指出原来用回热度作为回热器的评价指标与回热循环的热力分析参变数之不足,并建议用回热器的平均当量传热温差代替之。为此,在一些传统简化假定条件下,本文给出了基于新的分析准则的回热循环效率与最佳压比的解析表达式,以及一些典型计算结果曲线。在新的准则下,燃气轮机最佳压比数值随温比变化不大,其平均值约为3。另外,文中还分析了回热循环在有间冷与再热的情况下以及在基本保证回热器大小不变的条件下的循环特性。

It is pointed out that the classical recuperative effectiveness is not an appropriate evaluation criterion for the gas turbine recuperator or the recuperative gas turbine cycles. Another parameter-average heat transfer temperature difference in the recuperator is recommended as the new criterion instead of the recuperator effectiveness. The analytic expressions of the simple recuperative cycle efficiency and the optimum pressure ratio based on the new criterion are derived on the general simplified, assumptions. Some typical calculation results are presented also. With this new criterion, the optimum pressure ratio for efficiency of simple-recuperative gas turbine cycle does not vary a lot with temperature ratio and is approximately equal to 3. A similar analysis for the recuperative gas turbine cycle with intercooler and reheater and an analysis ensuring approximately constant recuperator heat transfer area are given also.