Blade Coupling Structure for Turbine Vibration Control
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Solution Overview
Problem
Turbine systems face vibration issues due to loose coupling of blades with rotor disks, leading to noise and efficiency deterioration, primarily caused by assembly tolerance and thermal expansion gaps.
Innovation Solution
A blade coupling structure is introduced, featuring a root elastic member and a wedge member between the coupling slot and blade root, where the wedge member and root elastic member press each other to securely fix the blade root to the coupling slot, utilizing a radially shaped wedge body with an inclined portion and cooling fluid passages to enhance coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a predetermined gap is provided between the coupling slot and blade root to account for thermal expansion, then the blade can accommodate thermal expansion, but the blade becomes loosely fixed causing vibration and noise
Solution Approach 1:
The patent changes the physical state of the coupling interface by introducing an elastic member that can dynamically adjust its compression state. The elastic member transitions from a loose state (allowing thermal expansion) to a compressed state (providing tight coupling), thereby adapting the coupling parameters to different operational conditions.
Solution Approach 2:
The elastic member acts as an intermediary between the coupling slot and blade root, mediating the interaction between thermal expansion requirements and coupling stability. This intermediary component absorbs the thermal expansion movements while maintaining continuous contact and coupling force.
2Ease of manufacture
If assembly tolerance is allowed in the coupling slot and blade root, then manufacturing is easier, but the blade is not tightly fixed resulting in vibration
Solution Approach 1:
The elastic member changes the force parameters in the coupling interface, generating sufficient elastic force to compensate for assembly tolerances. This elastic force ensures tight coupling between the blade and rotor disk even when manufacturing tolerances are not extremely tight.
Solution Approach 2:
The elastic member serves as a mediator that compensates for the gaps created by assembly tolerance. It fills the tolerance gaps and maintains continuous contact between the coupling surfaces, preventing vibration and noise while allowing easier manufacturing.
3Stability of the object's composition
If additional fasteners are used to secure the blade to the rotor disk, then coupling stability improves, but device complexity increases
Solution Approach 1:
The patent extracts the fastening function from separate fastener components and integrates it into the elastic member itself. The elastic member simultaneously provides both the coupling structure and the securing force, eliminating the need for additional fasteners and reducing overall device complexity.
Solution Approach 2:
The patent merges the coupling structure and the securing mechanism into a single integrated elastic member. This unified component performs both functions - providing the structural connection and generating the securing force through elastic deformation - thereby simplifying the overall assembly.
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 securely fixes the blade to the rotor disk, reducing vibration, noise, and maintaining operating efficiency by applying an elastic force without additional fasteners, effectively addressing the coupling tolerance and thermal expansion challenges.
Implementation Method 1
a root elastic member disposed between an inner end of the coupling slot and a root end of the blade root; and a wedge member disposed between the root elastic member and the inner end of the coupling slot. The wedge member and the root elastic member may press each other and may press the root end so that the blade root is fixedly coupled to the coupling slot.
Data Source
AI summary
A blade coupling structure and a turbine system having the same securely couple a blade to a rotor disk. The blade coupling structure includes a root elastic member disposed between a root end of a blade root of the blade and an inner end of a coupling slot formed in the rotor disk; and a wedge member having a wedge body fitted between the root elastic member and the inner end of the coupling slot. The wedge member and the root elastic member press each other and press the root end so that the blade root is fixedly coupled to the coupling slot. A flat portion of the wedge member contacts the root elastic member, and an inclined portion of the wedge member facilitates the fitting of the wedge body. A wedge passage is formed in non-contact regions of the wedge body and passes a cooling fluid to the blade.