Turbofan Fan Blade Stiffening via Interlocking Platform Edges
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Solution Overview
Problem
Existing fan blade designs lack sufficient stiffness, leading to instability and increased risk of flutter, which affects the performance and weight of turbofan engines.
Innovation Solution
The fan design incorporates a hub portion with platforms that extend radially outward, featuring interlocking or meshing edges with the spinner and aft seal plate, allowing for enhanced force transfer and increased natural frequency of the blades, thereby improving stability and reducing material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fan blade design uses conventional structures, then manufacturing is simpler, but blade stiffness is insufficient leading to flutter instability
Solution Approach 1:
The fan blade is divided into multiple functional segments: airfoil section, platform section, root section with dovetail, and attachment features. This segmentation allows each part to be optimized independently for stiffness while maintaining manufacturability of individual components.
Solution Approach 2:
The patent employs composite construction combining rigid materials in the airfoil and platform sections with attachment features that provide both structural support and flexibility for stress distribution. The composite structure achieves high stiffness-to-weight ratio.
2Weight of moving object
If fan blade mass is reduced for weight savings, then engine weight decreases, but blade natural frequency decreases increasing flutter risk
Solution Approach 1:
The blade design implements local quality optimization by concentrating mass in critical regions (airfoil leading edge, platform root area) while using lighter materials in less critical sections. This localized mass distribution maintains natural frequency while reducing overall weight.
Solution Approach 2:
The design incorporates preliminary stiffening features in the blade structure including optimized thickness distribution and attachment geometry that pre-establish high natural frequency characteristics before operational loads are applied, enabling weight reduction without compromising flutter margin.
3Ease of manufacture
If blade attachment features are simplified, then manufacturing is easier, but force transfer capability and stability are reduced
Solution Approach 1:
The attachment design merges multiple functions into integrated features: the dovetail root geometry simultaneously provides mechanical attachment, stress distribution, and alignment functions. The platform and root structures are combined to create unified force transfer paths, reducing the number of separate components while maintaining strength.
Data Source
AI summary
A fan is disclosed herein. The fan includes a hub portion operable to rotate about an axis. The hub portion extends along the axis between forward and aft ends. The fan also includes at least one platform operably fixed with the hub portion. The at least one platform at least partially encircles the axis. The fan also includes at least one airfoil extending from the at least one platform radially outward relative to the axis between a base and a tip. The at least one platform terminates at forward and aft circumferential edges spaced from one another along the axis. At least one of the forward and aft circumferential edges extends about the axis and along the axis.