Variable Fillet Guide Vane Stress Reduction
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Solution Overview
Problem
Compressor guide vanes in gas turbine engines experience significant wear, high vibrations, and stress, leading to potential cracking and defects, particularly at the button corner where structural parts intersect.
Innovation Solution
A guide vane design featuring a first button, trunnion, and airfoil with a variable fillet extending into the overhang portion, including sections of different radii, such as a bulge for local thickening to reduce vibrations and stress, and tapered sections for airflow and material efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a constant radius fillet is used between the button and airfoil, then the manufacturing process is simplified, but the stress and vibrations at the button corner increase leading to cracking and defects
Solution Approach 1:
The patent applies local quality by transitioning from a constant radius fillet to a variable radius fillet where the radius changes along the length of the fillet. Specifically, the fillet has a first radius near the button corner and a second radius at the distal end, with the first radius being larger than the second radius. This local variation in geometry provides enhanced stress distribution and vibration reduction at the critical button corner region while maintaining aerodynamic performance in the distal region.
Solution Approach 2:
The patent implements parameter changes by modifying the radius parameter of the fillet from a constant value to a variable value that changes along its length. The radius parameter transitions from a larger first radius near the button to a smaller second radius at the distal end. This parameter variation allows the fillet to simultaneously address stress concentration at the button corner and maintain aerodynamic efficiency in the airflow region.
2Reliability
If material is added to thicken the button corner region, then stress and vibrations are reduced, but the weight and material usage increase
Solution Approach 1:
The variable radius fillet creates a localized thickening effect at the button corner region through the larger first radius, providing enhanced structural strength and vibration resistance precisely where needed. The fillet gradually transitions to a smaller second radius toward the distal end, avoiding unnecessary material addition in regions where structural support is less critical, thus minimizing overall weight increase.
Solution Approach 2:
The patent utilizes curvature by employing a variable radius fillet that creates a smooth, curved transition between the button and airfoil. The fillet's curved geometry, with radius varying from r1 at the button to r2 at the distal end, distributes stress more effectively compared to sharp corners or linear transitions. This curved design provides structural reinforcement through geometric optimization rather than simple material addition.
3Reliability
If a larger fillet radius is used at the button corner, then stress concentration is reduced, but the airflow characteristics and material efficiency deteriorate
Solution Approach 1:
The variable radius fillet applies local quality by using a larger first radius near the button corner to reduce stress concentration and a smaller second radius at the distal end to optimize airflow characteristics. This spatially varying geometry ensures that each region of the fillet is optimized for its specific functional requirements: structural integrity at the button and aerodynamic performance in the airflow region.
Solution Approach 2:
The patent implements parameter changes by varying the radius parameter along the length of the fillet. The radius transitions from a larger value (first radius) near the button to a smaller value (second radius) at the distal end. This parameter variation allows the design to simultaneously achieve stress reduction at the button corner and maintain efficient airflow characteristics in the distal region.
Data Source
AI summary
A guide vane is disclosed. The guide vane includes a button, a trunnion connected to the button, and an airfoil connected to the button. The airfoil includes an overhang portion wherein the overhang portion extends from one end of the button to a distal end of the airfoil. The guide vane includes a button corner located near the beginning of the overhang portion. The guide vane includes a variable fillet extending into the overhang portion. The variable fillet includes sections of different radiuses along the length of the fillet.