SMA Actuation for Variable Area Fan Nozzle
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing petal actuation systems in turbofan engines require large forces and mechanical components that lead to wear and maintenance issues, increasing noise during high-thrust events like takeoff.
Innovation Solution
The use of shape memory alloy (SMA) actuators that change shape through heating, eliminating rotating or sliding mechanical components and minimizing force requirements, with one-way and two-way SMA actuators arranged near the trailing edges of petals to control angular positions and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If mechanical actuators with rotating or sliding components are used to deflect petals, then large forces can be applied to move the petals, but mechanical friction and wear increase leading to maintenance issues
Solution Approach 1:
The patent replaces traditional mechanical actuators with shape memory alloy (SMA) actuators that use thermal actuation instead of mechanical rotating or sliding components. The SMA actuators change shape in response to temperature changes, eliminating friction and wear associated with mechanical contacts while still providing sufficient force to deflect the petals.
Solution Approach 2:
The patent utilizes the temperature-dependent shape change properties of shape memory alloy materials. By controlling the temperature of the SMA actuators, the system changes the physical state and shape of the actuators to produce the desired petal deflection, replacing force-based mechanical actuation with temperature-based actuation.
2Reliability
If traditional mechanical actuators are used for petal deflection, then reliable force transmission is achieved, but the actuators weigh more and require more maintenance
Solution Approach 1:
The patent replaces heavy mechanical actuators with lightweight shape memory alloy actuators. The SMA actuators achieve reliable force transmission through their inherent shape memory properties and elastic recovery, eliminating the need for heavy mechanical components while maintaining actuation reliability.
3Power
If the fan nozzle throat area is reduced to increase exhaust velocity, then thrust is increased, but noise generation increases
Solution Approach 1:
The patent implements a dynamic fan nozzle throat area control system using shape memory alloy actuators that can adjust the throat area in real-time based on operating conditions. This dynamic adjustment allows the system to optimize the balance between thrust generation and noise reduction by varying the throat area as needed, rather than being fixed.
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
The SMA actuation system reduces wear and maintenance, minimizes aerodynamic drag, and effectively adjusts the fan nozzle throat area to reduce noise during high-thrust events while maintaining dependability by ensuring petals stay at commanded positions in case of failure.
Implementation Method 1
the deformable actuators comprise shape memory alloys (SMA) which have been trained to change shape in specific manners when energized (i.e., heated)
Implementation Method 2
Each SMA actuator is shaped to act as a fairing to reduce aerodynamic drag. The use of SMA actuators enables the design of lighter flow control surfaces by restoring the hoop strength of the nacelle at the trailing edge.
Data Source
AI summary
A variable area fan nozzle comprising an array of hinged rigid petals and a petal actuation system in which the principle of actuation is realized by changes in shape (i.e., deformation) of the actuators rather than by movement of cooperating mechanical parts. Because these actuators have no rotating or sliding mechanical components, wear and associated maintenance are reduced. Each deformable actuator has a portion made of shape memory alloy that has been trained to change shape in a specific manner when heated to a temperature above a transition temperature. In addition, each shape memory alloy actuator is shaped to act as a fairing to reduce aerodynamic drag.