SMA Airfoil Clearance Device for Gas Turbine Fan Blade Impact
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Solution Overview
Problem
Gas turbine engine fan blades often suffer damage due to contact with the fan casing, leading to load transfer and potential engine failure, with existing solutions like honeycomb materials being costly and increasing weight and size.
Innovation Solution
The implementation of airfoils with a clearance device utilizing a shape memory alloy (SMA) that can move to create clearance between the airfoil and other components, allowing for controlled deformation and reduced load transfer, thereby mitigating damage and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If honeycomb material or trench-filler material is used in the fan casing to mitigate load transfer, then the fan casing can better withstand blade contact, but the fan casing becomes larger, heavier, and more costly
Solution Approach 1:
The airfoil is designed with a deformable structure that allows it to dynamically change its shape during operation. The intermediate portion can deform in response to blade contact events, absorbing impact energy through controlled deformation rather than requiring a heavy, rigid fan casing structure. This dynamic response reduces the need for excessive structural reinforcement in the fan casing.
Solution Approach 2:
The airfoil's structural parameters are optimized to allow controlled deformation. The intermediate portion between the root and tip is designed with specific material properties and geometric characteristics that enable it to deform elastically or plastically under impact loads, changing its mechanical behavior from rigid to compliant. This parameter optimization allows the airfoil to mitigate load transfer without requiring heavy fan casing reinforcement.
2Strength
If honeycomb material or trench-filler material is used in the fan casing to mitigate load transfer, then the fan casing can better withstand blade contact, but the fan casing becomes more costly
Solution Approach 1:
The deformable airfoil structure with its intermediate portion designed for controlled deformation provides a more cost-effective solution compared to incorporating expensive honeycomb or trench-filler materials into the fan casing. The airfoil itself becomes the active element for mitigating load transfer, eliminating the need for costly special materials in the fan casing construction.
Solution Approach 2:
The airfoil structure serves multiple functions: it maintains aerodynamic performance during normal operation and automatically mitigates load transfer during blade contact events through its inherent deformable design. This self-service capability eliminates the need for additional protective materials in the fan casing, reducing manufacturing costs.
3Stability of the object's composition
If the airfoil is made more rigid to prevent deformation during operation, then aerodynamic performance is maintained, but load transfer to the fan casing increases during contact events
Solution Approach 1:
The airfoil is designed with non-uniform structural properties along its span. The intermediate portion between the root and tip has optimized material composition, thickness, or geometric characteristics that enable controlled deformation, while other portions maintain higher rigidity for aerodynamic stability. This local quality differentiation allows the airfoil to simultaneously maintain overall stability and provide localized compliance for load mitigation.
Solution Approach 2:
The airfoil transitions from a static, uniformly rigid structure to a dynamic structure with varying stiffness characteristics. The intermediate portion is designed to deform under specific load conditions while other portions maintain structural integrity. This dynamic behavior allows the airfoil to adapt its rigidity based on operational conditions, maintaining stability during normal operation and providing compliance during contact events.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides a reliable, lightweight, and compact configuration that reduces the risk of fan blade out events and minimizes the need for immediate repair by enabling controlled clearance and deformation, thus enhancing engine performance and safety.
Implementation Method 1
a clearance device formed of a shape memory alloy and disposed between the root portion and the tip portion
Data Source
AI summary
An airfoil arrangement for a gas turbine engine may include a clearance device using a shape memory alloy movable to provide clearance between an airfoil and one or more other components of the gas turbine engine. The clearance device may be formed as part of a fan blade. The arrangement may be configured to reduce overall weight and dimensions of the gas turbine engine.