Turbofan Thrust Reverser Linkage Obstruction Reduction
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Solution Overview
Problem
Thrust reversers in turbofan engines face challenges in reducing linkage obstruction within the bypass airflow duct, which affects propulsion efficiency and noise levels during forward and reverse aircraft motion.
Innovation Solution
A multi-armed linkage system with pivotal connections and joints that allow the blocker door to move between stowed and deployed states without obstructing the bypass airflow path, featuring a translating structure and a cascade array for diverting airflow, and a compound-motion mechanism that minimizes linkage extension into the airflow path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a multi-armed linkage system is used to position the blocker door, then the blocker door can move between stowed and deployed states effectively, but the linkage may obstruct the bypass airflow path
Solution Approach 1:
The linkage system is designed to operate in a dimension or space that does not interfere with the primary airflow path. The arms are configured to move the blocker door while staying radially inward or in a plane that minimizes projection into the bypass airflow, effectively changing the dimensional arrangement to avoid obstruction.
Solution Approach 2:
The linkage is divided into multiple arms (first arm, second arm, third arm) connected by joints, allowing each segment to be positioned independently. This segmentation enables the linkage to achieve the necessary blocker door positioning while minimizing the overall footprint and obstruction in the airflow path.
2Productivity
If the linkage system is designed to minimize obstruction, then airflow efficiency is improved, but the complexity of the linkage mechanism increases
Solution Approach 1:
The multi-armed linkage system serves multiple functions: it positions the blocker door, provides structural support, and guides the motion path. By making the linkage multi-functional, the design achieves airflow efficiency without requiring additional separate components, thereby managing complexity.
Solution Approach 2:
The linkage arms and joints are designed to combine several functions into a single integrated mechanism. The arms simultaneously provide structural support, transmit motion, and define the movement path of the blocker door, reducing the need for separate components and simplifying the overall system.
3Adaptability or versatility
If the blocker door is deployed to redirect airflow for reverse propulsion, then rearward propulsion is achieved, but forward propulsion efficiency is compromised
Solution Approach 1:
The blocker door and linkage system are designed to be dynamic, allowing the aircraft to transition between forward and reverse propulsion modes. The blocker door can be positioned in different states (stowed, deployed, partially deployed) to adapt to different operational requirements, enabling the system to optimize performance for either forward or reverse thrust as needed.
Solution Approach 2:
The thrust reverser system operates periodically, being deployed only when reverse propulsion is required (such as during landing deceleration) and retracted during normal forward flight. This periodic action ensures that forward propulsion efficiency is maintained during the majority of flight time while still providing adaptability when reverse thrust is needed.
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 solution enhances airflow efficiency and reduces noise by ensuring the linkage does not obstruct the bypass airflow during normal flight conditions and effectively redirects airflow for reverse propulsion without compromising forward propulsion efficiency.
Implementation Method 1
a blocker door device according to one, non-limiting, embodiment of the present disclosure includes a blocker door; a first arm pivotally connected to the blocker door; a second arm pivotally connected to the first arm; and a third arm pivotally connected to the second arm
Implementation Method 2
a multi-armed linkage system with pivotal connections and joints that allow the blocker door to move between stowed and deployed states
Implementation Method 3
a translating structure constructed and arranged to move between a first position and second position
Implementation Method 4
a cascade array engaged to the fixed structure and for diverting a bypass flowpath defined in-part by the blocker door
Data Source
AI summary
A thrust reverser of a turbofan engine has a translating structure and a blocker door device capable of diverting a bypass flowpath for reversing propulsion direction. The translating structure moves axially between a forward position and a rearward position and thereby drives a compound motion of a blocker door of the blocker door device that moves between a respective stowed state and a deployed state. The compound motion is attributable through the blocker door being pivotally engaged to the translating structure, and through a multi-armed linkage of the device being pivotally engaged between a stationary structure, the blocker door and the translating structure. The linkage is further orientated such that it does not appreciably obstruct the bypass flowpath when the blocker door is in the stowed state.