Three-D axial-flow turbine stage

Abstract

An object of the present invention is to reduce the adverse effect of interference between stationary blades and moving blades on the performance of an axial-flow turbine and to provide a high-performance turbine stage. Each of the stationary blades has a trailing edge convex toward a face side with respect to a radial line radially extending from the axis of the rotor shaft, and the each of the moving blades has a blade center-of-gravity line convex toward the face side with respect to a radial line radially extending from the axis of the rotor shaft, and shapes of the stationary blades and the moving blades meet conditions expressed by:where, thetant and thetanr are angles between the stationary blade tip and the stationary blade root, and radial lines, and thetabt and thetabr are angles between the blade center-of-gravity line of the moving blade at the tip of the same, and the blade center-of-gravity line of the moving blade at the tip of the moving blade, and radial lines.

Description

technical field [0001] The present invention relates to an axial flow turbine, in particular to a turbine stage which can greatly improve the efficiency of the turbine. Background technique [0002] In recent years, securing the reliability and improving the efficiency of axial flow turbines used in power plants has become an important issue from the viewpoint of environmental issues and energy saving. [0003] Generally, axial flow turbines, such as steam turbines, such as Figure 7 As shown, the stage is formed by a plurality of fixed blades 3 fixedly arranged between the fixed blade outer wheel 1 and the fixed blade inner wheel 2, and a plurality of moving blades fixedly arranged on the rotating shaft 4 and provided with a shroud 5 on the top. These stages are combined axially into a single stage or multiple stages to form a steam turbine. Recently, in this regard, three-dimensional blades have been proposed for the purpose of improving the overall efficiency of the turb...

AI Technical Summary

Problems solved by technology

This pressure rise is related to the inclination angle of the fixed blade at the front end of the blade and the inclination angle of the moving blade. Through the mutual setting of the inclination angle of the moving blade 6 and the fixed blade 3, the pressure difference between the outlet of the fixed blade and the outlet of the moving blade changes. Large, the leakage loss increases, and there is a problem that the efficiency of the turbine stage is reduced

For example, when the inclination angle θbr of the front end of the moving blade is set to be smaller than the inclination angle θnt of the front end of the fixed blade, the pressure increase caused by the inclination angle of the front end of the fixed blade exceeds the pressure increase caused by the inclination angle of the front end of the moving blade, and the pressure difference at the front end of the moving blade becomes larger, the leakage loss increases

[0016] As mentioned above, the shape of the three-dimensional blades (blade inclination angle) in the turbine stage is related to the fixed blade 3 and the moving blade 6. Only by reducing the binary flow loss of the fixed blade 3 and moving blade 6 respectively, it cannot fully improve the class performance

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