Thrust Reverser Oblique Flow Redirection
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Solution Overview
Problem
Conventional thrust reversers for aerial vehicles direct a portion of the gas turbine engine airflow vertically, reducing efficiency and increasing stopping distance, especially at lower ground speeds, as they are often stowed to inhibit airflow into the auxiliary power unit inlet.
Innovation Solution
A thrust reverser design with a housing and movable doors that transition between stowed and deployed positions, featuring a unique curvature and pivot mechanism, allowing the exhaust flow to be redirected obliquely, improving efficiency and enabling operation at lower ground speeds by minimizing reverse flow impingement on the aircraft tail and auxiliary power unit inlet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the thrust reverser directs exhaust flow vertically in the deployed state, then reverse thrust is generated to decelerate the aircraft, but the efficiency of the thrust reverser is reduced
Solution Approach 1:
The patent changes the flow direction parameter from vertical to forward-oblique direction. The doors are configured with specific curvature and angle to redirect exhaust flow forward at an oblique angle rather than vertically upward, transforming the flow trajectory to improve thrust reverser efficiency while maintaining deceleration capability
Solution Approach 2:
The patent transitions from vertical (upward) flow redirection to forward-oblique flow redirection. By changing the spatial dimension of exhaust flow direction from the vertical axis to a forward-leaning oblique axis, the system achieves better efficiency while still providing effective reverse thrust for aircraft deceleration
2Reliability
If the thrust reverser is stowed at lower ground speeds to inhibit airflow into the auxiliary power unit inlet, then the auxiliary power unit is protected, but the stopping distance of the aircraft is increased
Solution Approach 1:
The patent changes the operational parameter threshold for thrust reverser deployment. Instead of stowing at lower ground speeds, the system maintains deployed state down to lower speeds by using the forward-oblique flow direction that prevents exhaust from entering the auxiliary power unit inlet, thus extending the operational range and reducing stopping distance
Solution Approach 2:
The patent enables dynamic operation of the thrust reverser at lower ground speeds by configuring the flow path to adaptively direct exhaust away from the auxiliary power unit inlet. This allows the system to remain deployed longer during deceleration, improving stopping performance while protecting the auxiliary power unit through intelligent flow management
3Reliability
If the doors are rotatable about a door angle less than 40 degrees, then the curvature matching seal is achieved, but the structural complexity increases
Solution Approach 1:
The patent employs curved leading edges on the doors that match the curvature of the inner flange. This spherical/curved geometry allows the doors to conform to the housing contour when rotated to less than 40 degrees, creating an effective seal without requiring complex sealing mechanisms, as the curvature itself provides the sealing interface
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 thrust reverser enhances efficiency by directing exhaust flow forward, reducing stopping distance and maintaining deployment at slower speeds, while minimizing wear on actuators and improving reliability through load transfer to the housing.
Implementation Method 1
the pair of doors are configured to direct at least a portion of the exhaust flow substantially along an axis oblique to a centerline of the engine
Implementation Method 2
the leading edge of each door of the pair of doors is in contact with the at least one inner flange to form a seal
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A thrust reverser for an aerial vehicle is coupled to an engine associated with the aerial vehicle. The thrust reverser includes a housing configured to receive an exhaust flow. The housing is movable relative to the aerial vehicle between at least a first, stowed position and a second, deployed position. The housing includes at least one inner flange that defines a first curvature. The thrust reverser includes a pair of doors coupled to the housing. The pair of doors is movable between at least a first position and a second position based on a movement of the housing. Each door of the pair of doors includes a leading edge and a trailing edge. The trailing edge is downstream from the leading edge in a direction of the exhaust flow through the housing, and the leading edge has a second curvature that is substantially the same as the first curvature.