Damped Heatshield Assembly for Gas Turbine Seal Stability
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Solution Overview
Problem
Gas turbine engines experience significant vibration issues due to resonance, coincidence, and aeroelastic instability, which can lead to increased interference and sealing problems between the heatshield and static seal members, particularly within a specific vibration excitation range.
Innovation Solution
A heatshield assembly with a cylindrical body supported exclusively at its axial ends, featuring a damper member, such as a split ring, seated in a groove at the radially inner side to attenuate vibrations, and seal members on the outer side to manage vibration-induced interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heatshield is supported exclusively at axial ends, then the seal members can effectively seal with the shaft, but vibration within the excitation range causes interference and sealing problems
Solution Approach 1:
A damper member is introduced as an intermediary element between the heatshield and the shaft. The damper member absorbs and attenuates vibrations, preventing them from reaching the seal members and causing interference. This mediator resolves the contradiction by isolating the sealing interface from harmful vibrations while maintaining the exclusive axial end support structure.
Solution Approach 2:
The damper member converts the harmful vibration energy into beneficial damping effects. By positioning the damper member adjacent to the seal members, the vibration attenuation directly protects the sealing interface, transforming the problematic vibration into an opportunity to enhance sealing reliability through targeted vibration control.
2Productivity
If the heatshield operates in the vibration excitation range, then it can function within the required dimensional parameters, but resonance and aeroelastic instability occur
Solution Approach 1:
The damper member transforms the harmful resonance and aeroelastic instability effects into beneficial vibration attenuation. By operating within the excitation range and using the damper member to counteract vibrations, the system maintains full operational capability while achieving enhanced vibrational stability through the damping effect.
3Length of stationary object
If the heatshield is made longer to cover more shaft length, then it provides better thermal protection, but it becomes more susceptible to vibration within the excitation range
Solution Approach 1:
The damper member serves as a protective intermediary that allows the heatshield to be longer without proportionally increasing vibration susceptibility. The damper member attenuates vibrations along the heatshield length, enabling extended thermal protection coverage while maintaining vibrational stability through the damping effect.
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
The solution effectively attenuates vibrations within the specified range, reducing interference and maintaining effective sealing while avoiding airflow disruptions, thus enhancing the operational stability and efficiency of the gas turbine engine.
Implementation Method 1
A damper member is disposed at the radially inner side of the heatshield for attenuating vibration of the heatshield
Data Source
AI summary
A gas turbine engine includes a shaft and a heatshield that circumscribes the shaft. The heatshield defines a cylindrical body that has radially inner and outer sides and extends between first and second axial ends. The heatshield is exclusively supported on the shaft at the first and second axial ends. The heatshield includes at least one seal member on the radially outer side. A damper member is disposed at the radially inner side of the heatshield for attenuating vibration of the heatshield.