Turbine Rotor Locking Plates with Articulation for Sealing
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Solution Overview
Problem
Existing turbine rotor blade locking arrangements face challenges in maintaining consistent loading and damping of vibrations while accommodating manufacturing tolerances and thermal expansion, leading to issues with sealing and performance due to variable gap spaces between locking plates.
Innovation Solution
The design features annular grooves in the rotor disc and blades to trap locking plates with a sectorial contour, allowing articulation and minimizing gap spaces for improved sealing and balanced loading, ensuring the plates remain effective during transients without locking up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gap spaces between locking plates are made narrow to improve sealing, then sealing efficiency is improved, but the locking plates lock up during start-up phase
Solution Approach 1:
The locking plates are designed with articulation capability, allowing them to rotate about their radial center during start-up when thermal expansion is minimal. This dynamic movement prevents locking up during transient phases while maintaining narrow gap spaces for improved sealing during normal operation.
Solution Approach 2:
The patent changes the gap space parameter from a fixed dimension to a variable dimension that adapts during operation. The gap spaces are intentionally made narrow for sealing, but the locking plates can change their position through articulation, effectively varying the gap dimension during start-up to prevent locking.
2Weight of moving object
If locking plates are made thinner to reduce weight, then weight is reduced, but thermal expansion occurs more quickly causing articulation issues
Solution Approach 1:
The locking plates are designed to articulate dynamically in response to thermal expansion. The thinner plates expand faster, but this is accommodated through controlled articulation movement, allowing the system to adapt to the rapid thermal changes without compromising structural integrity or sealing.
Solution Approach 2:
The patent accepts and utilizes the parameter change of faster thermal expansion in thinner plates. By designing the locking mechanism to accommodate this parameter change through articulation, the weight reduction benefit is achieved while managing the thermal expansion characteristic.
3Manufacturing precision
If manufacturing tolerances are tightened to improve loading consistency, then loading balance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The locking plates are designed with articulation freedom to dynamically adjust to manufacturing tolerances in the grooves. This dynamic capability compensates for tolerance variations, maintaining consistent loading and damping performance without requiring extremely tight manufacturing tolerances.
Solution Approach 2:
The patent introduces a degree of freedom (articulation parameter) that allows the locking plates to adjust their position and orientation. This parameter change enables the system to accommodate manufacturing tolerances while maintaining performance consistency.
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 configuration enhances the sealing efficiency, reduces leakage, and maintains consistent damping of blade vibrations, thereby improving the performance and reliability of the turbine engine.
Implementation Method 1
the thermal inertia of the locking plates is smaller and thus their thermal expansion is quicker than for the rotor disc and the rotor blades
Implementation Method 2
the loading due to the centrifugal forces of the locking plates onto the blades above it
Data Source
AI summary
A turbine rotor with a rotor disc, a plurality of slots arranged on the rotor disc, a plurality of blades having blade roots and arranged in the slots, and a plurality of locking plates fitted in a position between the rotor disc and the blades are provided. The first gaps on radially outside edges and second gaps on radially inside edges, relative to an axis of rotation of the rotor disc, are formed between neighboring locking plates. At least one of the first gaps is smaller than the corresponding second gap, wherein at least one first gap and corresponding second gaps are intentionally introduced.