【作者】 杨进才；

【导师】 郭仁宁； 曹群星；

【作者基本信息】 辽宁工程技术大学 ， 动力工程， 2006， 硕士

【摘要】 汽轮机组的运行状况对整个电网的发供电质量和效益有着至关重要的影响,因此保证机组的安全、可靠、经济运行已成为当前十分重要的课题。汽轮机经常运行于变工况下,因此在变工况下安全性和经济性显得尤为重要,其中低真空就是变工况的一种。本文只限于讨论低真空变工况的情况。传统观点认为,当凝汽式汽轮机背压升高即真空降低时,最末级反动度增大,轴向推力增加,对汽轮机的安全运行产生较大影响。因此,研究汽轮机背压变化时轴向推力的变化特性具有十分重要的意义。本文通过对汽轮机变工况计算方法的改进,计算分析了赵各庄热电厂12MW凝汽式汽轮机背压升高后其最末级反动度、最末级前后及动叶前后压差、最末级轴向推力变化规律。该结论对凝汽式汽轮机的低真空供热改造与运行具有一定的指导意义。更多还原

【Abstract】 The operating condition of steam turbine is of great significance to the quality and profit of generating and providing electricity in the whole power grid. Therefore, to ensure the units’security, reliability and economic operation has become a quite important problem at present. Steam turbine often operates in variable working condition, thus the security and economy in this case is especially important, and low vacuum is one kind. The following text only limits in discussing the variable working condition of low vacuum..As is traditionally said, the degree of reaction and the axial thrust are increased with the back pressure increasing, which has a great influence on the security of steam turbine. Therefore, studying the operating characteristics of the steam turbine’s axial thrust with the back pressure changing is very important.In this paper, the calculating method for steam turbine at off-design condition is improved. And the changing characteristics such as the degree of reaction, the pressure drop, the axial thrust at the last stage and the total axial thrust of the steam turbine with the back pressure increasing are analyzed by calculation by taking a 12MW condensing steam turbine as an example. The conclusion is helpful to operation of condensing steam turbine with lower vacuum.更多还原