Thrust Reverser Flap Actuation for Aircraft Nacelle
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Solution Overview
Problem
Existing thrust reverser devices for aircraft engines face issues with high irregular forces and deformation in the flap mechanism due to sudden contact with secondary air flow, leading to potential degradation of deflection grids and aerodynamic inefficiencies.
Innovation Solution
A thrust reverser device with a movable cowl and secondary air flow blocking flaps, where the flaps are integrated with deflection grids and mobilized using jacks and cylinders, allowing for a two-stage transition from direct to reverse jet operation, with flaps deployed and retracted to manage airflow effectively, and featuring a combined actuator system for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the movable cowl is moved downstream to deploy the thrust reverser, then the reverse jet operation is enabled, but the blocking flaps suddenly contact the secondary air flow causing high irregular forces and deformation
Solution Approach 1:
The patent applies preliminary action by moving the blocking flaps to their deployed position before the movable cowl reaches the position where they would contact the secondary air flow. The flaps are positioned in advance during the cowl translation phase, so when the cowl moves downstream and the flaps are deployed, they are already in the correct position and do not suddenly contact the air flow, preventing high irregular forces and deformation.
2Productivity
If the blocking flaps are deployed to block secondary air flow, then reverse thrust is achieved, but the connecting rods and flow disturbance occur degrading the deflection grids
Solution Approach 1:
The patent applies the taking out principle by removing the connecting rods from the system entirely. Instead of using connecting rods to deploy the blocking flaps, the invention uses a direct actuation mechanism where the movable cowl itself or integrated actuators on the cowl deploy the flaps. This elimination of connecting rods removes the source of flow disturbance and protects the deflection grids from degradation.
3Ease of operation
If the flaps are stored under the deflection grids during cowl retraction, then the passage is closed for direct jet operation, but high irregular forces occur when flaps suddenly contact air flow
Solution Approach 1:
The patent applies preliminary action by positioning the blocking flaps in their deployed state before the cowl begins its retraction movement. As the cowl moves upstream during retraction, the flaps are already in position to gradually block the air flow, preventing sudden contact and the associated high irregular forces. This staged approach allows smooth transition while maintaining ease of operation.
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 interference, minimizes deformation, and enhances the aeramatch ratio by ensuring smooth airflow transitions, improving both aerodynamic and acoustic performance during take-off and flight.
Implementation Method 1
a downstream edge mounted on a lever articulated relative to said set of deflection grids
Implementation Method 2
cylinders integral with the sets of deflection grids which each have an endless screw on which a joint is integral with the upstream edge of a flap is forced to move
Implementation Method 3
the reduction of the aéramatch is ensured by at least one of the following means: the intervals between the side edges of the shutters are occupied by movable triangular inter-shutters
Data Source
Figure 1~4
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Figure 8~10'
AI summary
The present disclosure provides a thrust reverser device that is integrated in an aircraft nacelle. Blocking flaps are stored inside a mobile cowl disposed in a downstream section of the nacelle, under deflection cascade assemblies during direct-jet operation of the nacelle. Various devices are provided for executing the passage from direct-jet operation to reverse-jet operation in two stages: the mobile cowl moves in translation towards the downstream end of the nacelle; and each flap is then deployed in the main air flow path.