Vortex-Generating Fins for Jet Engine Reverser Flap Leakage
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Solution Overview
Problem
The existing turbofan designs with reverser flaps experience rearward leaks due to high-speed air flow, counteracting the braking effect intended by deploying these flaps, necessitating a solution to minimize these leaks.
Innovation Solution
Incorporating vortex-generating fins across leakage windows in the reverser flaps, which transform the leaking air into low-energy vortices, reducing the impact of these leaks by altering the airflow pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reverser flaps are deployed across the bypass duct to redirect air flow for reverse thrust, then braking effectiveness is improved, but air leaks through operational clearances create rearward flow that reduces braking effectiveness
Solution Approach 1:
The patent applies the 'Blessing in disguise' principle by converting the harmful rearward-flowing leaked air into beneficial low-energy vortices through vortex-generating fins. These fins, positioned at the downstream edge of the reverser flap, transform the leak flow direction and energy characteristics, causing the previously harmful rearward flow to rotate forward and merge with the main reversed air flow, thereby contributing to reverse thrust rather than counteracting it.
Solution Approach 2:
The patent applies the 'Parameter changes' principle by modifying the flow parameters (direction and energy) of the leaked air through the vortex-generating fins. The fins change the flow angle and induce rotation, transforming the leaked air from a high-speed rearward flow into a low-energy forward-rotating vortex that aligns with the desired reverse thrust direction.
2Productivity
If high-speed air flow is maintained in the bypass duct for efficient thrust generation, then engine performance is improved, but the same high-speed flow increases the harmful effect of air leaks when reverser flaps are deployed
Solution Approach 1:
The vortex-generating fins convert the harmful high-speed leaked air into beneficial low-energy vortices. The fins extract kinetic energy from the high-speed leak flow and transform it into rotational motion, reducing the forward momentum that causes rearward flow and creating vortices that contribute to reverse thrust.
Solution Approach 2:
The patent changes the flow parameters by using vortex-generating fins to reduce the speed and alter the direction of the leaked air. The fins create a pressure gradient and induce rotation, transforming the high-speed rearward flow into a low-energy forward-rotating vortex that no longer counteracts the reverse thrust.
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 introduction of vortex-generating fins significantly reduces the rearward thrust counteracting the braking effect, enhancing the effectiveness of the reverser flaps by minimizing air leaks and maintaining thrust directionality.
Implementation Method 1
at least one reverser flap has at least one fin extending across the leakage window... the fins which transform the flows of air from the leaks into low-energy vortices
Data Source
AI summary
A turbofan comprising a motor and a nacelle, surrounding the motor, where a duct for a bypass flow is delimited between the nacelle and the motor and in which a flow of air flows. The nacelle comprises reverser flaps where each one is articulated between a stowed position in which it is not in the bypass duct and a deployed position in which it is across the bypass duct. The turbofan has at least one reverser flap with at least one leakage window configured to allow airflow in the deployed position. The at least one reverser flap has at least one fin extending across the leakage window.