Работа осевой турбинной ступени в области малорасходных режимов. Общие положения

Abstract

The involvement of power units of thermal power plants (and many power units of nuclear power plants in the near future) to regulate the frequency in the electric network leads to the expansion of shutdowns or equipment deep unloading at night. This circumstance negatively affects the reliability, efficiency and service life of power plants. With significant unloading the operation of turbines is accompanied by ventilation power losses, ventilation heating, and a significant increase in the axial flexural-torsional resonance vibrations of the working blades of the steam turbine at the last stages. In addition, at low-flow rates, the maximum erosive wear of the input edges of the working blades of the last stages by coarsely dispersed droplet-impact moisture and their outlet edges occurs by the reverse currents of the vapor-droplet mixture and moisture particles sucked from the condenser and the outlet pipe of the exhaust part of the LPC into the flow path of the cylinder. On the one hand, the nature of the steam flow spatial structure at low-flow modes of steam turbines operation is well studied. But on the other hand it needs to bring to the used terminology uniformity and clarify the characteristics of the modes.