SMA Actuated Aerostructure for Variable Geometry Fan Nozzle
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Solution Overview
Problem
Conventional turbofan engines face a tradeoff between noise attenuation and thrust loss due to the use of chevrons, which generate drag and are not optimal for varying flight conditions, necessitating a solution that reduces noise without degrading fuel efficiency or increasing drag during cruise.
Innovation Solution
A shape memory alloy (SMA) actuated aerostructure that dynamically changes shape in response to flight conditions by using SMA actuators to morph fan nozzles and chevrons, allowing for variable geometry configurations that reduce noise during takeoff without compromising fuel efficiency during cruise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If chevrons are used to suppress noise, then noise attenuation is improved, but drag increases and thrust is lost
Solution Approach 1:
The patent applies variable geometry chevrons that can dynamically change their configuration between extended and retracted positions. During takeoff and landing, the chevrons are extended into the exhaust flow to suppress noise. During cruise, the chevrons are retracted to minimize drag and thrust loss. This dynamic adaptability resolves the contradiction by allowing noise suppression only when needed, rather than continuously.
2Use of energy by moving object
If fan nozzle diameter is reduced for cruise performance, then fuel efficiency is improved, but takeoff and landing performance deteriorates
Solution Approach 1:
The patent employs a variable area fan nozzle that can dynamically adjust its diameter. During cruise, the nozzle diameter is reduced to improve fuel efficiency and engine performance. During takeoff and landing, the nozzle diameter is increased to ensure adequate thrust and safety. This dynamic resizing of the fan nozzle resolves the contradiction between fuel efficiency and operational safety.
3Adaptability or versatility
If variable geometry configurations are implemented, then adaptability to flight conditions is improved, but device complexity increases
Solution Approach 1:
The patent utilizes flexible chevron structures and variable geometry components that can change shape and position. These flexible elements allow the engine nozzle and chevrons to adapt to different flight conditions (takeoff, cruise, landing) by changing their configuration, thereby improving adaptability while managing structural complexity through the use of flexible materials and mechanisms.
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 actuated aerostructure effectively reduces noise during takeoff while maintaining fuel efficiency during cruise by altering the fan nozzle area and chevron geometry, minimizing drag and thrust loss, thus optimizing aircraft performance across different flight phases.
Implementation Method 1
A shape memory alloy (SMA) actuated aerostructure operable to dynamically change shape according to flight conditions
Data Source
AI summary
A shape memory alloy (SMA) actuated aerostructure operable to dynamically change shape according to flight conditions is disclosed. Deformable structures are actuated by SMA actuators that are coupled to face sheets of the deformable structures. Actuating the SMA actuators produces complex shape changes of the deformable structures by activating shape changes of the SMA actuators. The SMA actuators are actuated via an active or passive temperature change based on operating conditions. The SMA actuated aerostructure can be used for morphable nozzles such as a variable area fan nozzle and/or a variable geometry chevron of a jet engine to reduce engine noise during takeoff without degrading fuel burn during cruise.