摘要
目前采用的汽轮机理想循环热效率受到相对内效率影响而不能准确反映汽轮机热力系统运行经济状态。同时,等效热降法计算中需要预先已知汽轮机排汽焓及回热抽汽状态点的焓值,而凝汽式汽轮机排汽焓及处于湿蒸汽区回热抽汽点焓值不能准确确定,从而导致等效热降法计算结果产生误差。针对上述问题,文中首先对理想循环热效率的定义方法进行了改进。然后,基于改进的理想循环热效率,提出了等效热降法的改进算法。该方法利用蒸汽等熵膨胀过程来确定等效热降,不仅避开了求解汽轮机排汽焓的难题,而且还可以分析引起热力系统经济性降低的原因和部位,从而为汽轮机热力系统经济性诊断提供了依据。通过与常规等效热降法计算结果的对比,证明了该改进方法的正确性。
The ideal cycle heat efficiency used nowadays is affected by the relative internal efficiency so it can't reflect the operation economic state of thermal system of steam turbine. At the same time, in calculating process of equivalent enthalpy drop method, the exhaust steam of steam turbine and regenerative extraction steam enthalpies need determining in advance. But for condensing steam turbine, the exhaust steam enthalpy and the enthalpy of regenerative extraction steam in wet steam state region can't be determined accurately. These cause the calculation results of equivalent enthalpy drop method with error. To counter the problems above, the defining method of ideal cycle heat efficiency is improved firstly. Then based on the improved ideal cycle heat efficiency, the improved equivalent enthalpy drop method is given. In the new method, the equivalent enthalpy drops are obtained by isentropic expanding process of steam in turbine. By the improved equivalent enthalpy drop method, not only the difficulty of determining the exhaust steam enthalpy can be avoid, but also the reason and position that cause the economy of thermal system of steam turbine to can be analyzed, and the basis for thermal economy diagnosis can be provided. Through comparing with the calculation results of usual equivalent enthalpy drop method, the correctness of the improved method is proved.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2004年第12期243-247,共5页
Proceedings of the CSEE
