Common Endwall Contour for Gas Turbine Airfoil Platform Gaps
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Solution Overview
Problem
In gas turbine engines, varying platform geometries between airfoil passages result in aerodynamic mismatches and increased costs due to the need for different seals at platform gaps, leading to inefficiencies and higher costs.
Innovation Solution
The airfoil array features a common endwall contour shape that extends across gaps between adjacent platforms, ensuring a smooth and continuous surface regardless of platform geometry, allowing for a single type of seal to be used and reducing the aerodynamic impact of mismatches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the endwall contour shape is scaled to fit varying passage shapes, then the endwall shape adapts to different airfoil geometries, but aerodynamic mismatches are created at the platform gap resulting in increased loss
Solution Approach 1:
The endwall contour is divided into multiple segments: a first endwall contour segment for first airfoils, a second endwall contour segment for second airfoils, and a common endwall contour segment that spans the platform gap. This segmentation allows each segment to be optimized for its specific airfoil type while the common segment ensures continuity across the gap, eliminating aerodynamic mismatches.
Solution Approach 2:
Different portions of the endwall are given different contour characteristics tailored to local requirements. The first and second endwall contour segments have specific shapes optimized for their respective airfoil types, while the common endwall contour segment provides a standardized interface at the gap. This local differentiation resolves the contradiction by allowing adaptation where needed while maintaining uniformity where it matters for aerodynamic continuity.
2Manufacturing precision
If different endwall contour shapes are designed for each passage, then the endwall fits each passage shape, but different seals are required at each platform gap increasing cost
Solution Approach 1:
The common endwall contour segment serves as a universal interface that spans all platform gaps regardless of the specific airfoil types adjacent to the gap. This universal segment allows a single seal design to be used across all gaps, eliminating the need for multiple seal types while maintaining precise fit for different airfoil geometries through the specialized first and second contour segments.
Solution Approach 2:
The invention merges the adaptive first endwall contour segment, the adaptive second endwall contour segment, and the universal common endwall contour segment into a unified endwall structure. This combination achieves both passage-specific precision and gap-uniformity, allowing a single seal type to function across all gaps while maintaining optimal fit for varying airfoil geometries.
3Ease of manufacture
If a common endwall contour shape is used across all passages, then the same seal can be used at all platform gaps, but aerodynamic mismatches occur at the platform gaps
Solution Approach 1:
The endwall contour is segmented into adaptive portions (first and second endwall contour segments) that compensate for geometric variations and a common portion that provides seal-friendly continuity. This segmentation allows the system to achieve both seal standardization and aerodynamic efficiency by placing the common segment specifically at the gap region where seals are located.
Solution Approach 2:
The solution applies local quality by making the endwall contour properties location-dependent: the first and second segments provide location-specific adaptation for different airfoil types, while the common segment provides location-specific uniformity for seal compatibility. This local differentiation eliminates aerodynamic losses while maintaining manufacturing simplicity.
Data Source
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AI summary
An airfoil array (60) for a gas turbine engine comprises a plurality of airfoils (62) spaced circumferentially apart from each other about an engine center axis. Each airfoil is associated with a platform (68a, 68b). An endwall (64) extends circumferentially about the engine center axis, and is defined by adjacent platforms (68a, 68b). Each pair of adjacent platforms (68a, 68b) are separated from each other by a gap (80). An endwall contour shape extends from a first location on one side of the gap to a second location on an opposite of the gap (80). The endwall contour shape is the same for all adjacent platforms (68a, 68b).