Fan Platform Leading Edge Tab for Gas Turbine Stability
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Solution Overview
Problem
In gas turbine engines, the twisting of interblade platforms under operational forces can create gaps and alter the air flow path, affecting aerodynamic performance due to their thin design and circumferential loads, leading to inefficient airflow across the fan section.
Innovation Solution
A tab is mounted to the inner surface of the platform, extending circumferentially to resist movement and maintain a controlled flow surface, ensuring the platforms remain closer to cylindrical shape and providing a smooth airflow path, which can be integrally molded with the platform using carbon composite materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the platforms are made thin to reduce weight, then the weight is reduced, but the platforms twist under operational forces creating gaps and altering airflow paths
Solution Approach 1:
The platform is divided into multiple segments: the main platform body and protruding tabs at the leading edge. These tabs act as separate structural elements that provide reinforcement without significantly increasing the overall weight of the platform. The segmentation allows the thin platform to maintain stability through distributed support points.
Solution Approach 2:
The platform and tabs are constructed using composite materials, specifically carbon fiber reinforced plastic (CFRP). This composite structure provides high strength-to-weight ratio, allowing the platform to remain thin and lightweight while maintaining structural integrity and resistance to twisting under operational forces.
2Productivity
If the platforms are made thin to improve aerodynamic efficiency, then the aerodynamic performance is improved, but the platforms create scoops at the leading edge due to twisting
Solution Approach 1:
The tabs are positioned at the leading edge of the platforms to preemptively counteract twisting forces before they can create scoops. By placing the reinforcement elements at the critical leading edge location, the design prevents the formation of gaps and maintains a smooth airflow path from the outset.
Solution Approach 2:
The tabs provide localized reinforcement specifically at the leading edge where twisting forces are most problematic. This local quality enhancement addresses the specific issue of scoop formation without requiring thickening of the entire platform, thereby preserving overall aerodynamic efficiency.
3Force
If the platforms are allowed to twist under operational forces, then the platforms can accommodate circumferential loads, but the flow path profile is altered and aerodynamic performance is affected
Solution Approach 1:
The tabs act as counterbalancing elements that resist the twisting moments generated by circumferential loads. By providing opposing structural support at the leading edge, the tabs counteract the tendency of the platform to rotate or deform, maintaining consistent flow path geometry despite operational forces.
Data Source
Figure 1
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Figure 3A~5
AI summary
A platform for a gas turbine engine has an outer surface and an inner surface. The inner surface is provided with a mount location for mounting the platform to a rotor. The platform extends from a leading edge to a trailing edge, and between a suction wall and a pressure wall. A circumferential direction is defined between the suction wall and the pressure wall. A tab extend circumferentially outward of one of the suction and pressure walls from the platform. The tab has a circumferentially outermost portion which will abut an inner surface of an adjacent platform when the platform is mounted. A fan section and a gas turbine engine are also disclosed.