Gas Turbine Liner Reduces Vibratory Stress on Guide Vanes
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Solution Overview
Problem
Existing gas turbine engines face challenges in reducing vibratory stresses on structural guide vanes to meet the Goodman capability, which is technically difficult and often requires modifications to airfoil parts, materials, or vibration sources.
Innovation Solution
A liner is positioned between the aft end of the fan case and the translating sleeve to reduce vibratory stress on the structural guide vane, with a thickness capable of attenuating vibrations below 1,000 Hertz, and is placed along the inner diameter, between the structural guide vane and inner fixed structures, or on the translating sleeve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If modifications are made to airfoil parts, material properties, or steady stress to reduce vibratory stresses, then the Goodman capability is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
A liner is introduced as an intermediary component between the fan case and the structural guide vane. The liner absorbs and attenuates vibratory energy, reducing the stress transmitted to the guide vane. This mediator approach allows the original airfoil design to be maintained while achieving reduced vibratory stresses and improved Goodman capability.
Solution Approach 2:
The patent replaces mechanical modifications to the airfoil structure with an acoustic/ vibrational control solution. Instead of changing the airfoil geometry or material properties to reduce stress, a liner is used to actively dampen vibrations, substituting a passive structural approach with an active vibrational control mechanism.
2Reliability
If the liner thickness is increased to attenuate vibrations below 1,000 Hertz, then the vibratory stress reduction is improved, but the device complexity and space requirements increase
Solution Approach 1:
The liner thickness is optimized to specific parameter ranges that are effective for attenuating vibrations in the target frequency range (below 1,000 Hertz). By carefully selecting the thickness parameter, the liner achieves maximum vibratory stress reduction while minimizing the volume occupied. The thickness is tuned to resonate with and cancel the problematic vibration frequencies.
3Reliability
If the liner is positioned in multiple locations (inner diameter, between guide vane and fixed structure, on translating sleeve), then the vibratory stress attenuation is improved, but the device complexity increases
Solution Approach 1:
The liner is positioned at specific locations where vibratory stress is most problematic: along the inner diameter, between the guide vane trailing edge and fixed structure, and on the translating sleeve. Each positioning location targets a specific vibration source or stress concentration area, providing localized attenuation where it is most needed while maintaining overall system simplicity.
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 reduces vibratory stress by up to 50% compared to a hard-wall configuration, without modifying the structural guide vane's properties, by tuning the liner to the resonant frequency of the structural guide vane, thereby reducing unsteady pressure and component resonant stress.
Implementation Method 1
the liner includes a thickness capable of attenuating vibrations having a frequency of less than 1,000 Hertz
Implementation Method 2
tuning the liner to the resonant frequency of the structural guide vane
Implementation Method 3
by tuning the liner to the resonant frequency of the structural guide vane, thereby reducing unsteady pressure and component resonant stress
Data Source
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AI summary
A gas turbine engine (100) is provided having a fan case (112) and a translating sleeve (127) positioned downstream from the fan case. A flow channel (102) extends between the fan case and the translating sleeve. The flow channel includes an inner diameter (108) and an outer diameter (110). A structural guide vane (116) is positioned within the flow channel and extends from the inner diameter to the outer diameter. A liner (200) is positioned between an aft end of the fan case and an aft end of the translating sleeve to reduce vibratory stress on the structural guide vane.