Flexible Turbine Shield Mounting for Vibration Damping
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Solution Overview
Problem
Existing methods for attaching shielding to turbine engine structures face challenges such as limited lifespan due to thermal inertia and stiffness differences, increased mass from thick shielding, and complex assembly requirements, which can lead to progressive detachment and vibrations detrimental to safety.
Innovation Solution
A flexible fixing method is employed, using tangential connections between the shielding and casing with spring blades for vibration damping, optimizing connection distribution to minimize forces and extend lifespan, while maintaining mechanical strength and thermal insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the shield is fixed by numerous assembly flanges or screws to ensure mechanical strength, then the retention capacity is improved, but the lifespan is limited due to thermal inertia and stiffness differences causing progressive detachment and vibrations
Solution Approach 1:
The patent transitions from rigid fixed connections to flexible connections that can dynamically adapt to thermomechanical variations. The flexible connection allows relative movement between the shield and casing, accommodating differential thermal expansion and stiffness variations without causing progressive detachment, thereby extending lifespan while maintaining retention capacity.
Solution Approach 2:
The patent changes the mechanical parameters of the connection system by introducing flexibility. Instead of using rigid flanges and screws with fixed stiffness, the invention employs flexible connections with adjustable compliance that can adapt to varying thermal and mechanical conditions, preventing the vibration and detachment issues that limit lifespan.
2Strength
If the shield thickness is increased to improve retention capacity in hot air environment, then the retention capacity is improved, but the mass increases significantly
Solution Approach 1:
The patent introduces a cold air flow intermediary between the hot air environment and the shield. This cold air barrier maintains the shield at lower temperature, reducing thermal stress and allowing thinner shield sections while maintaining retention capacity. The mass reduction is achieved without compromising safety by using the cold air flow as a protective intermediary layer.
3Manufacturing precision
If precise centering pins and adjustment devices are used to ensure proper positioning, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
The patent employs flexible connections that self-adjust to the correct position through their inherent flexibility. The flexible connection allows the shield to naturally align with the casing during assembly without requiring external centering pins or complex adjustment mechanisms. The system self-regulates positioning through the flexible element's mechanical properties, simplifying the assembly process while maintaining precision.
4Strength
If rigid mounting is used to ensure mechanical strength, then the strength is improved, but the vibratory positioning and forces transmitted to motor structure increase
Solution Approach 1:
The patent replaces rigid static connections with flexible dynamic connections that can absorb and dampen vibrations. The flexible connection acts as a vibration isolator, reducing the transmission of harmful vibratory forces to the motor structure while maintaining the necessary mechanical strength for retention. The dynamic flexibility allows the system to accommodate vibratory movements without compromising structural integrity.
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 solution enhances the retention of debris, reduces shielding thickness, and simplifies assembly, ensuring robustness and safety by controlling vibratory positioning and mechanical strength under thermomechanical loading, thereby improving the overall performance and reliability of the turbine engine shielding.
Implementation Method 1
vibration damping is also ensured via annular spring blades arranged between the shielding and the casing
Implementation Method 2
a flexible coupling between them capable of providing vibratory positioning
Implementation Method 3
tangential connection the shield on the casing between points of the shielding and of the casing sufficiently far apart depending on the curvature of the shielding and of the casing between these points so as to achieve a flexible coupling between them capable of providing vibratory positioning
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to negating the thermal inertia of a solid portion, such as shielding, which influences the mechanical behavior of the parts of the engine structure. In particular, the invention aims to reduce the forces transmitted to the engine structure during an event in which a turbine blade ruptures, while at the same time preserving the mechanical strength thereof and suitable vibratory positioning. To this end, the invention provides a flexible fastener for the shield, thereby enabling a fusible section to be produced. An exemplary assembly for mounting shielding (15) onto a casing (20) of the engine structure (30) of a turbine (10) according to the invention comprises connection lugs (70) and points (82, 92) for attachment to the casing (20) and to the shielding (15). The attachment points are sufficiently spaced apart in accordance with the curvature of the shielding (15) and casing (20) such that the connection between the lugs (70) and the shielding (15) or casing (20), as well as the connection to the attachment points (92, 82), are substantially tangential. The lugs (70) are sized such that the connection has a sufficient degree of flexibility in order to control the vibratory positioning thereof and to ensure a sufficient degree of mechanical strength under a thermomechanical loads.