Gas Turbine Platform Asymmetry for Alignment
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Solution Overview
Problem
In gas turbine engines, the misalignment of adjacent components' radially facing surfaces due to manufacturing tolerances and operational loads leads to turbulence and localized hot spots, which can reduce durability and increase cooling requirements.
Innovation Solution
The design includes a component with a platform having varying thicknesses between mate faces, with a greater thickness adjacent to the suction side and a lesser thickness adjacent to the pressure side, and a contour that slopes inwardly from the radially facing surface toward the mate face, along with a seal member that spans the intersegment gap and tilts to form an acute angle with the mate face, ensuring proper alignment and reducing hot spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If adjacent components are assembled with standard manufacturing tolerances, then assembly is simplified, but misalignment of radially facing surfaces occurs leading to turbulence and hot spots
Solution Approach 1:
The platform is designed with non-uniform thickness, having a first thickness adjacent to the suction side and a second thickness adjacent to the pressure side. This local variation in geometry compensates for expected misalignment, ensuring that the radially facing surfaces remain properly aligned during operation despite manufacturing tolerances and operational loads.
Solution Approach 2:
The platform thickness is pre-configured during manufacturing to anticipate and compensate for future misalignment that will occur during operation. By building in the thickness variation beforehand, the design proactively addresses the alignment problem before it manifests, eliminating turbulence and hot spots without requiring complex adjustment mechanisms.
2Reliability
If uniform platform thickness is used, then manufacturing is simpler, but misalignment creates turbulence and localized hot spots reducing durability
Solution Approach 1:
The platform employs different thicknesses in different regions: a first thickness adjacent to the suction side and a second thickness adjacent to the pressure side. This localized geometric variation ensures proper alignment of radially facing surfaces, eliminating turbulence and hot spots, thereby improving component durability and reliability.
Solution Approach 2:
The platform thickness parameter is deliberately varied across the platform width rather than maintaining a constant value. This parameter change from uniform to non-uniform thickness directly addresses the alignment issue, improving reliability by preventing misalignment-related failures while remaining manufacturable.
3Manufacturing precision
If thicker platform is used throughout, then alignment tolerance is increased, but component weight and cooling requirements increase
Solution Approach 1:
Instead of uniformly increasing platform thickness, the design applies thickness variation locally: a first thickness adjacent to the suction side and a second thickness adjacent to the pressure side. This targeted approach provides the necessary alignment tolerance only where needed, avoiding unnecessary weight increase in other regions of the component.
Solution Approach 2:
The platform exhibits asymmetric thickness distribution, with different thicknesses on opposite sides. This asymmetric geometry provides alignment compensation without requiring overall thickening of the component, thereby maintaining optimal weight-to-strength ratio and cooling efficiency.
Data Source
AI summary
A component for a gas turbine engine according to an example of the present disclosure includes, among other things, an airfoil section extending in a radial direction from a platform, the airfoil section extending in an axial direction between an airfoil leading edge and an airfoil trailing edge, and the airfoil section extending in the circumferential direction between pressure and suction sides. The platform extends in the axial direction between a platform leading edge and a platform trailing edge, and extends in the circumferential direction between a first mate face and a second mate face. The platform has a radially facing surface joined with the airfoil section and has a cold side surface opposed to the radially facing surface. A first thickness is defined between the radially facing surface and the cold side surface adjacent the first mate face, and a second thickness is defined between the radially facing surface and the cold side surface adjacent the second mate face. The first thickness is greater than the second thickness from at least the airfoil leading edge to the airfoil trailing edge with respect to the axial direction. A method of assembly is also disclosed.