The Reforming Design And Operating Analysis Of Provision-heating In Low Vacuum Of The Turbine

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.