Curved Blade Platform Geometry for Accurate Circumferential Clearance
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Solution Overview
Problem
The existing blade structures in gas turbine engines face issues with inaccurate measurement of circumferential clearance and dynamic balance due to angular twist of blades, leading to potential safety hazards and performance degradation under high-temperature and high-pressure conditions.
Innovation Solution
A blade platform design featuring a pair of side edges with linear and curved portions, where the slopes of the curved portions are in the same direction and tangent to each other, allowing adjacent blades to rotate uniformly and maintain consistent circumferential clearance, eliminating the need for intermediate locking parts and simplifying the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an inclined-edge platform structure is used to increase blade solidity and installation angle, then the number of blades can be increased and aerodynamic performance improved, but the blade platforms will not interfere with each other after twisting, causing circumferential clearance to increase and measurement accuracy to deteriorate
Solution Approach 1:
The blade platform edge is designed with a curved portion instead of a straight line, where the curvature radius is specifically configured to ensure that when blades twist under external force, the curved surfaces of adjacent platforms make contact with each other. This prevents the platforms from moving in the same direction and maintains accurate circumferential clearance measurements while preserving the inclined-edge structure for high blade solidity.
2Ease of operation
If blade platforms are designed with straight edges and constant gradient to allow twisting without interference, then blades can rotate freely under external force, but the actual circumferential clearance becomes different from designed clearance, creating safety hazards
Solution Approach 1:
By configuring curved portions on the blade platform edges with specific curvature radii, the design ensures that when blades rotate or twist under external forces during operation, the curved surfaces of adjacent platforms contact each other. This contact mechanism prevents excessive circumferential clearance accumulation while allowing necessary blade movement, thereby maintaining both operational freedom and engine safety.
3Measurement precision
If intermediate locking parts are added between blade platforms to prevent gap formation, then the structural complexity increases and manufacturing difficulty increases, but the circumferential clearance accuracy can be maintained
Solution Approach 1:
The curved portion design inherently provides the locking function by ensuring contact between adjacent blade platforms when twisted, eliminating the need for separate intermediate locking parts. The curvature radius is specifically configured to maintain appropriate gaps during normal operation while preventing excessive circumferential clearance, thereby maintaining measurement accuracy without increasing structural complexity.
4Productivity
If the platform edge is designed with curved portions with specific curvature radius, then the number of blades can be increased while maintaining accurate circumferential clearance measurements, but the manufacturing precision requirements increase
Solution Approach 1:
The curved portion is designed with a specific curvature radius that balances the need for increased blade count with manufacturability. The curvature provides the necessary geometric constraint to maintain accurate circumferential clearance measurements while allowing a higher density of blades on the rotor. The specific radius configuration ensures that the curved surfaces contact appropriately during operation without requiring extreme manufacturing tolerances.
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
Ensures accurate circumferential clearance and dynamic balance tests, prevents blade interference, and enhances the efficiency and safety of gas turbine engines by maintaining proper load transmission and installation angles.
Implementation Method 1
the fir-tree root of the blade is attached to a working surface of the groove of the disk for load transmission due to the centrifugal force
Data Source
AI summary
A blade platform, comprising a pair of side edges and a pair of bottom edges, wherein the side edge comprises a linear portion and a curved portion, wherein the linear portion comprises a first linear portion and a second linear portion, and the curved portion comprises a first curved portion and a second curved portion; wherein the first linear portion and the second linear portion are connected to two ends of the curved portion and are tangent to the curved portion, slopes of the first curved portion and the second curved portion are in the same direction and the first curved portion and the second curved portion are circumscribed. The benefits of the blade platform are that the problems of platforms pushing against each other and get stuck during the working state as in the prior art or lack of accuracy in the test results of the blade circumferential clearance test and the dynamic balance test can be avoided.