An improvement of performance in steam turbine by developing three-dimensionally designed blades

From the viewpoint of reducing power generation costs and saving energy res ources, improved efficiency of thermal power plants is a critical issue. St eam turbines, which are the main plant equipment, have been developed which provide a high level in blade performance. Further enhancement of blade pe rformance, however, requires refinement of the blade shape and the control flow pattern in the radial direction. Recently, development of three-dimens ionally designed blades has been active, with goals of raising the internal efficiency and being able to the control flow pattern in the radial direct ion not only for stationary blades, but also for moving blades((1)-(3)). In order to improve the flow pattern through the blade rows, the authors have proposed three-dimensionally designed stationary blades((4)-(7)), which ca n be used in low pressure (LP) and high and intermediate pressure (HIP) tur bines. This paper describes the development of three-dimensionally designed blades, in which performance of turbine stages including moving blades has been improved. The new blades reduce the end-wall losses in the HIP stages where there is a serious problem with secondary flow.