Method to flow parameters non-uniformity reduction in the after-extraction stages of two-tier low-pressure turbine

摘要

This paper provides the specific features of the steam flow in the near extraction upper tier's stages of the low-pressure turbine (LPT) with elevated capacity and the influence of the flow structure to the after-extraction stage's efficiency. Based on the numerical studies it has shown that the traditional regenerative steam extraction system through the annual gap between the stator parts makes a significant influence on the flow symmetry, distorting it in the circumferential direction, which in turn leads to the stage's efficiency decreasing. To prevent near extraction stages from work in non-uniformity flow parameters conditions a new regenerative steam extraction system with aerodynamic cutter is proposed. Various numerical investigations have confirmed the new steam extraction system efficiency in the way of stage's economy and operation reliability increasing by the non-uniformity flow parameters reduction in the circumferential direction.