Cascade Pivot Door Thrust Reverser Flow Area Optimization
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Solution Overview
Problem
Pivot door-type thrust reversers have limited reverse thrust effectiveness due to inefficient use of flow area, resulting in a smaller effective flow area compared to geometric area, which complicates housing and weight distribution, while cascade-type reversers achieve higher effectiveness but incur weight penalties.
Innovation Solution
A pivot door-type thrust reverser with a translatable cascade component that moves simultaneously with the pivot door to optimize airflow direction, utilizing almost 90% of the available flow area, allowing for a reduced geometric envelope and lighter, shorter doors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pivot door-type reverser design is used, then device complexity is reduced, but reverse thrust effectiveness is limited to 20-30% due to inefficient flow area utilization
Solution Approach 1:
The patent merges the pivot door mechanism with a cascade component into a single integrated assembly. The cascade component is mounted to the pivot door and moves simultaneously with it, combining the flow-blocking function of the pivot door with the flow-turning function of the cascade vanes. This integration allows the system to achieve cascade-type effectiveness (40%+) while maintaining simpler pivot door actuation mechanisms.
Solution Approach 2:
The cascade component is designed to be movable relative to the pivot door, allowing it to translate between deployed and retracted positions. This dynamic configuration enables the cascade vanes to be positioned optimally for flow redirection during reverse thrust operation, while being stowed during forward flight to minimize drag and maintain aerodynamic efficiency.
2Productivity
If cascade-type reverser is used, then reverse thrust effectiveness increases to near 40%, but weight penalty is incurred due to translating structure and cascade baskets
Solution Approach 1:
By merging the cascade component with the pivot door assembly, the patent eliminates the need for separate translating structures and cascade baskets required in traditional cascade-type reversers. The cascade vanes are mounted directly on the pivot door, which is already a moving component, thereby sharing the actuation mechanism and reducing overall system weight.
Solution Approach 2:
The pivot door serves multiple functions: it blocks forward flow during reverse thrust operation and simultaneously supports the cascade component for flow redirection. This multi-functionality reduces the need for additional dedicated components, thereby reducing overall weight while maintaining high reverse thrust effectiveness.
3Productivity
If pivot door length is increased to improve reverse thrust effectiveness, then aerodynamic equivalency is maintained, but structural loads increase and door must be adjusted rearward compromising nozzle envelope
Solution Approach 1:
The patent segments the flow control function into two distinct components: the pivot door for flow blocking and the cascade vanes for flow redirection. This segmentation allows each component to be optimized independently - the pivot door can be shorter with reduced structural loads, while the cascade vanes provide the additional aerodynamic effectiveness needed for high reverse thrust performance.
Solution Approach 2:
The cascade component adds a third dimension to the flow control mechanism by introducing vertically arranged vanes that redirect flow in the vertical direction. This dimensional addition provides enhanced flow redirection capability without requiring increased pivot door length, thereby avoiding the structural load and nozzle envelope compromise issues.
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 design enhances reverse thrust effectiveness by over 30% compared to standard pivot door-type reversers, reduces structural loads, and offsets the weight of the cascade component, achieving area match and efflux control similar to cascade-type reversers without weight penalties.
Implementation Method 1
actuators force the doors to rotate to a predetermined angle, blocking the rearward airflow and turning it forward at an angle approximately equal to the rotated door angle
Implementation Method 2
The cascade includes vanes specifically designed to both efficiently turn the airflow forward and control the efflux
Implementation Method 3
A pivot door-type thrust reverser with a translatable cascade component that moves simultaneously with the pivot door to optimize airflow direction
Data Source
AI summary
A thrust reverser for reversing a thrust of a turbofan engine of an aircraft. The reverser includes a pivot door, a cascade component, and an actuation system. The door is moveable between lowered and raised positions in which a side outlet is, respectively, covered and uncovered. The cascade includes turning vanes, and is moveable between forward and rearward positions in which the cascade is positioned, respectively, not over and over the side outlet. The actuation system deploys the reverser by simultaneously moving the door to the raised position and moving the cascade to the rearward position over the side outlet, and stows the reverser by simultaneously moving the cascade to the forward position and moving the door to the lowered position. When the door is raised and the cascade is over the side outlet, airflow through the side outlet is directed at least partially forward to provide reverse thrust.