Thrust Reverser Blocker Door Camming Mechanism
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Solution Overview
Problem
Conventional thrust reverser designs in high bypass turbofan engines suffer from increased aerodynamic drag and reduced performance due to blocker doors and link arms that protrude into the duct flow path during normal operation, causing surface interruptions, duct leakage, and exposure to damage.
Innovation Solution
A thrust reverser assembly with a translating cowl and pivotally coupled blocker door featuring a camming surface, where the blocker door is deployed into the bypass duct by an actuator-driven slider assembly, minimizing exposure during normal operation and reducing drag by concealing the door within the cowl when stowed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the blocker door is covered by the translating cowl during normal operation, then aerodynamic drag is reduced and performance is improved, but the blocker door may be exposed to damage or fail to deploy properly
Solution Approach 1:
The translating cowl is made movable between a retracted position (exposing the blocker door) and an extended position (covering the blocker door). This dynamic positioning allows the system to optimize aerodynamic performance during normal operation while protecting the blocker door, and ensures proper deployment when needed.
2Speed
If the blocker door and link arms are exposed during normal operation, then the thrust reverser can deploy quickly, but aerodynamic drag increases and performance decreases
Solution Approach 1:
The blocker door and link arms are extracted from the external airflow path by positioning them inside the engine nacelle, covered by the translating cowl during normal operation. This removes the source of aerodynamic drag while maintaining the ability to deploy quickly when the cowl retracts.
3Loss of energy
If the translating cowl is extended to cover the blocker door, then aerodynamic performance is improved, but the blocker door may not be accessible for maintenance or inspection
Solution Approach 1:
The translating cowl's movable design allows it to be extended for aerodynamic performance during operation, and retracted when maintenance or inspection is needed, providing both aerodynamic efficiency and accessibility.
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 reduces aerodynamic drag, maintains acoustic treatment integrity, and enhances engine performance and noise attenuation by preventing the blocker door from defining the duct flow surface during normal operation, thus improving thrust reverser efficiency and operational reliability.
Implementation Method 1
the blocker door having a camming surface... the slider assembly is adapted to slide in the slider track as the actuator moves axially, and interaction between the slider assembly and the camming surface of the slider track causes the blocker door to move from a stowed position to a deployed position by pivoting
Data Source
AI summary
The present disclosure relates generally to a thrust reverser for a gas turbine engine. As a translating cowl is translated aft from the nacelle of the gas turbine engine, a cascade is also translated in the aft direction and a blocker door coupled to the cascade is pivoted into a fan duct by means of a camming surface, thereby diverting air in the fan duct through the cascade. In the stowed position, both the cascade and the blocker door are disposed radially outward of a radially inner wall of the nacelle and/or the translating cowl.