Turbofan Inner Ring Reinforcement for Fan Blade Containment
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Solution Overview
Problem
Gas turbine engines face challenges in enhancing the reliability and safety against highly unlikely fan blade detachment events, known as FBO events, where broken fan blades can penetrate other engine components or escape, necessitating improved containment and impact resistance structures.
Innovation Solution
A turbofan gas turbine engine design incorporates a reinforcing structure integrated with the inner ring of the fan housing, positioned forward of the fan blades, to enhance impact resistance and modify the trajectory of detached blades, reducing forward axial motion and enhancing containment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fan containment structure is implemented to prevent fan blade penetration, then engine safety is improved, but the complexity of the device increases
Solution Approach 1:
The reinforcing structure is applied locally at the forward end of the radially protruding section where impact resistance is most needed, rather than uniformly across the entire inner ring. This localized reinforcement provides enhanced safety where fan blade impact is most likely while avoiding unnecessary complexity and weight elsewhere in the structure.
Solution Approach 2:
The inner ring is segmented into different functional zones: the radially protruding section with reinforcing structure for impact resistance, and other sections with standard containment functionality. This segmentation allows each part to be optimized for its specific purpose, improving overall safety without uniformly increasing device complexity.
2Strength
If the reinforcing structure is added to enhance impact resistance, then the strength of the inner ring is improved, but the weight of the stationary object increases
Solution Approach 1:
The reinforcing structure is strategically placed only at the forward end of the radially protruding section where impact resistance is critical, rather than reinforcing the entire inner ring. This localized approach enhances strength where needed while minimizing additional weight compared to uniform reinforcement.
Solution Approach 2:
Instead of providing excessive reinforcement across the entire inner ring, the design applies partial reinforcement only to the specific area (forward end of radially protruding section) that requires enhanced impact resistance, optimizing the balance between strength and weight.
Data Source
AI summary
Turbofan gas turbine engines and methods are provided. The engines include a fan assembly having an engine rotor hub with fan blades extending radially therefrom configured for rotation of the fan blades, a fan housing structure encircling the fan assembly and including an inner ring that defines an exposed inner surface of the fan housing structure that includes a radially protruding section that defines a recess facing the fan blades and encircling tips thereof, a fan containment structure within the fan housing structure positioned circumferentially around the fan assembly and axially encircling the radially protruding section, and a reinforcing structure fixed to or integrated with an annular portion of the inner ring that is configured to provide greater impact resistance to the forward end of the radially protruding section relative to an aft end thereof.