燃气轮机回热循环进一步新析—考虑平均传热温差与流阻的关系

NEW ANALYSIS OF RECUPERATIVE GAS TURBINE CYCLES——WITH THE RELATIONSHIP BETWEEN HEAT TRANSFER TEMPERATURE DIFFERENCE AND PRESSURE DROP INCLUDED

本文考虑了回热器传热温差与流动阻力损失的关系,进一步论证了燃气轮机回热循环的评价准则可采用传热温差代替传统的回热度。研究了典型的主表面式回热器传热温差与流动阻力损失的关系,探讨了考虑平均传热温差与流动阻力损失情况下,新的评价准则与燃气轮机回热循环压比、温比及效率的对应关系。并给出了回热循环效率与最佳压比的解析表达式。结果表明:燃气轮机循环效率、流动阻力损失随着平均传热温差的增大而降低。在新的准则下,燃气轮机最佳压比数值随温比变化不大,其平均值仍约为3。

With the relationship between the pressure drop and the heat transfer temperature difference in the gas turbine recuperator included, the heat transfer difference can be further recommended as the evaluation criterion instead of the recuperator effectiveness for recuperative gas turbine cycles. The relation of the heat transfer temperature difference and the pressure drop in a typical type of primary surface recuperator was investigated. The analytic expression of the simple recuperative cycle efficiency and the optimal pressure ratio based on the new criterion and the relationship were derived on the general simplified assumptions. As a result, the cycle efficiency and the pressure drop in the gas turbine recuperator decrease with the increase of the heat transfer temperature difference. With the new criterion, the optimal pressure ratio for the efficiency of the simple recuperative gas turbine cycle does not vary a lot with the temperature ratio and is also approximately equal to 3.