Variable Fillet Seal Rail for Turbine Blade Tip Shroud
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Solution Overview
Problem
Gas turbine engine tip shrouds face thermal and mechanical stresses, leading to interface wear, shingling, and increased bending stress, which existing designs fail to adequately address without increasing mass.
Innovation Solution
Incorporating a variable fillet on the tip shroud with a non-constant curvature that increases contact area between adjacent blades, reducing interface wear and bending stress while maintaining structural integrity and minimizing mass addition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant radius fillet is used on the seal rail, then the manufacturing process is simple, but the contact area between adjacent blades is insufficient leading to increased interface wear and shingling
Solution Approach 1:
The patent applies local quality by transitioning from a uniform constant radius fillet to a variable radius fillet where the curvature changes along the length of the seal rail. Specifically, the fillet has a larger radius at the leading end and a smaller radius at the trailing end, creating locally optimized contact characteristics that increase the contact area between adjacent blade tip shrouds while maintaining manufacturing feasibility through defined radius transitions.
2Reliability
If the fillet radius is increased to reduce interface wear, then the contact area improves, but the mass of the tip shroud increases
Solution Approach 1:
The patent applies parameter changes by varying the radius parameter of the fillet along the length of the seal rail rather than using a constant radius. The radius transitions from a larger value at the leading end to a smaller value at the trailing end, creating an optimized contact area that reduces interface wear and shingling while controlling the additional mass through controlled geometric variation rather than uniform radius increase.
3Reliability
If a variable fillet with varying curvature is implemented, then the contact area and local stiffness increase reducing wear and stress, but the manufacturing complexity increases
Solution Approach 1:
The patent implements local quality through a variable radius fillet design where different sections of the seal rail have different radius characteristics. The leading end portion has a larger radius for increased contact area and wear resistance, while the trailing end portion has a smaller radius. This localized optimization improves reliability at wear-prone areas without requiring complex variable curvature throughout the entire fillet, thereby managing manufacturing complexity.
Data Source
AI summary
A turbine blade assembly may be provided for use in a gas turbine engine. The turbine blade assembly may include an airfoil and a tip shroud. The airfoil may extend radially outward from an axis of rotation of the airfoil. The tip shroud may be located at a radial end of the airfoil. The tip shroud may include a seal rail that extends in a direction of rotation of the airfoil. A notch, including a Z-notch or a V-notch, may be situated on a first side of the seal rail at an end of the seal rail. A variable fillet may be situated on a second side of the seal rail that is opposite of the first side on which the notch is situated. The variable fillet is a fillet having a curvature that varies along a length of the second side.