Airfoil Module Segmentation for Thermal Stress Relief
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Solution Overview
Problem
Gas turbine engine airfoils face challenges in withstanding high thermal loads and structural stresses due to thermal expansion and contraction, leading to potential bending and cracking, as existing materials and cooling methods are limited in managing these conditions effectively.
Innovation Solution
The design incorporates a stator ring assembly with airfoil modules featuring a unitary piece vane assembly extending between outer and inner diameter ring assemblies, where the airfoil modules are joined at the outer diameter ring assembly and abut at the inner diameter ring assembly, allowing for independent thermal expansion while maintaining a fixed position through brazing or welding, and utilizing a feather seal to manage stress and strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If airfoils are retained in substantially fixed position to bear structural loads, then structural stability is improved, but stress and strain from thermal expansion/contraction increase leading to potential bending and cracking
Solution Approach 1:
The airfoil module is divided into multiple segments: a vane assembly and a ring assembly that can move independently relative to each other. The vane assembly is retained at a fixed position by retainers to bear structural loads, while the ring assembly can expand and contract axially to accommodate thermal changes. This segmentation allows the fixed vane to maintain structural stability while the movable ring relieves thermal stress.
Solution Approach 2:
The ring assembly is designed to be movable axially relative to the vane assembly, transitioning from a static fixed connection to a dynamic adjustable connection. The retainer allows the ring to move axially to accommodate thermal expansion and contraction, while still maintaining radial positioning to support structural loads. This dynamic capability prevents stress accumulation that would occur with a completely fixed structure.
2Temperature
If cooling capabilities are enhanced to increase turbine inlet temperature, then engine efficiency is improved, but material property limitations and cooling system complexity increase
Solution Approach 1:
The airfoil module separates the cooling function into a distinct ring assembly that can be independently designed and optimized. The ring assembly includes cooling channels and is thermally coupled to the vane assembly, allowing targeted cooling of critical areas without requiring complex cooling systems throughout the entire airfoil structure.
Solution Approach 2:
The ring assembly acts as an intermediary thermal management component between the hot gas environment and the vane assembly. It provides a dedicated cooling pathway and thermal barrier, simplifying the overall cooling system architecture by concentrating cooling functions in this intermediate structure rather than requiring complex internal cooling throughout the vane.
3Strength
If airfoils are permitted to move to ameliorate stress and strain from thermal expansion, then resistance to bending and cracking is improved, but structural stability and fixed position retention deteriorate
Solution Approach 1:
The airfoil module is segmented into a vane assembly and ring assembly with distinct functional roles. The vane assembly is fixed by retainers to maintain structural stability and bear loads, while the ring assembly is free to move axially to relieve thermal stress. This segmentation allows simultaneous achievement of both fixed position for stability and movement for stress relief.
Solution Approach 2:
The retainer provides a dynamic connection that allows axial movement of the ring assembly while maintaining radial positioning and structural support. This dynamic capability enables the structure to adapt to thermal changes without compromising the overall structural integrity and load-bearing capacity of the airfoil module.
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 structural integrity and operational life of airfoil modules by allowing thermal expansion while maintaining a fixed position, reducing stress and strain, and minimizing air leakage and localized wear, thereby improving the efficiency and durability of gas turbine engines.
Implementation Method 1
the airfoils experience structural loads from thermal expansion/contraction
Implementation Method 2
joined at the outer diameter ring assembly and abut at the inner diameter ring assembly, allowing for independent thermal expansion while maintaining a fixed position through brazing or welding
Implementation Method 3
joined at the outer diameter ring assembly and abut at the inner diameter ring assembly, allowing for independent thermal expansion while maintaining a fixed position through brazing or welding
Data Source
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AI summary
An airfoil module (45) may have an outer diameter ring assembly (50), a vane assembly (60) having a stator vane (61) and an inner diameter ring assembly (70). The outer diameter ring assembly (50) and the inner diameter ring assembly (70) may be arranged concentrically with the stator vane (61) of the vane assembly (60) extending between them. The inner diameter ring assembly (70) may have a first inner diameter ring section sealing end (71) and a second inner diameter ring section sealing end (73). A feather seal (76) may be disposed along the first inner diameter ring section sealing end (71). A stator ring assembly (60) may comprise multiple airfoil modules (45) arranged in an annulus. The outer diameter ring assemblies (50) may be joined together by brazing or welding, or may share a unified outer diameter ring assembly (50). The inner diameter ring (70) assemblies may abut feather seals (76) so that the airfoil modules (45) may expand and contract independently along the inner diameter ring assemblies (70).