Turbine Blade Axial Insertion Root With Center Cutout
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Solution Overview
Problem
Conventional turbine blade assemblies face challenges in maintaining uniform centrifugal fields during rotation and require complex assembly procedures, which can lead to nonuniform frictional forces and stress concentrations, especially when using wedge-shaped snubber type blades.
Innovation Solution
The turbine blade assembly features axial inserted blade root type blades with a shank portion and center cutout portion, utilizing stopper members and moving members to secure the blades in place, ensuring uniform centrifugal fields and improved mechanical strength by preventing axial movement and erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wedge-shaped snubber type blades are used to control radial directional position, then blade positioning is achieved, but nonuniform frictional forces and stress concentrations occur
Solution Approach 1:
The patent applies homogeneity by making all turbine blades have the same width and blade root portion dimensions, eliminating the wedge-shaped variation. This ensures uniform frictional forces and stress distribution across all blades during rotation, resolving the stress concentration problem while maintaining positioning precision through the uniform blade groove fit
Solution Approach 2:
The patent extracts the wedge-shaped snubber structure from the blade design, removing the source of nonuniform frictional forces. Instead of using varied blade shapes for positioning, the design relies on uniform blades with precise groove fitting, eliminating the harmful wedge-shaped geometry that caused stress concentrations
2Strength
If axial inserted blade root type is used to increase load capability, then blade strength is improved, but complex assembly procedures are required
Solution Approach 1:
The patent segments the blade root portion into distinct functional elements: the embedding portion that fits into the blade groove, the shank portion with center cutout, and the effective blade part. This segmentation allows for standardized mass production of uniform blade components that simplify assembly while maintaining the high load capability of the axial inserted blade root design
3Reliability
If stopper members are inserted into center cutout portions to prevent axial movement, then blade security is improved, but device complexity increases
Solution Approach 1:
The patent inverts the conventional approach by placing the stopper member inside the blade's center cutout portion rather than having external stopping mechanisms. The stopper protrudes from the blade groove and engages with the cutout, creating a compact integrated solution that prevents axial movement while adding minimal structural complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design maintains uniform centrifugal fields and enhances mechanical strength, reducing the risk of blade fall and stress concentrations, while simplifying assembly and improving reliability by securely fixing the blades without relying on screws or snubber friction.
Implementation Method 1
a stopper member, which prevents the turbine blade from moving in the axial direction of the turbine rotor, is inserted into each of the center cutout portions
Implementation Method 2
a through passage which is formed from the center cutout portion to the effective blade part, moves the stopper member toward the effective blade part within the center cutout portion and inserts therein a moving member which puts a side surface of the stopper member on the axial direction side of the turbine rotor and the inner wall surface of the center cutout portion into a contactable state
Implementation Method 3
the blade root portions of the turbine blades, comprising an embedding portion to be inserted into the blade grooves
Data Source
AI summary
A turbine blade 10a which is a stop blade is provided with a cutout portion 50 which is formed in one circumferential side surface 22a of a shank portion 22 at the center in the axial direction of a turbine rotor 100, a cutout portion 60 which is formed in one circumferential side surface 22a of the shank portion 22 from one end portion 22b to the cutout portion 50 in the axial direction of the turbine rotor 100, and a through passage 70 which is formed to pass from the cutout portion 50 to an effective blade part and in which a moving member 170, which moves a stopper member 160 to the effective blade part in the cutout portion 50, is inserted.