Turbojet Nacelle Thrust Reversal Door Flanks
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Solution Overview
Problem
Existing aircraft turbojet engine nacelles with thrust reversal devices face challenges in achieving efficient braking while maintaining aerodynamic continuity for propulsion, and the complexity of mechanisms for door spoilers can lead to failures and incomplete flow deflection.
Innovation Solution
The turbojet engine nacelle incorporates doors with a fixed structure that includes a deflection edge and flanks extending into a rebate, covering the counter-thrust opening sides, optimizing both direct and reverse flow guidance through a curved deflection edge and integrated flanks, ensuring efficient thrust reversal without additional mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a mechanism is added to retract the spoiler into the door, then the aerodynamic continuity is improved, but the device complexity increases and reliability decreases
Solution Approach 1:
The spoiler is extracted from the door structure and repositioned on the fixed structure upstream of the door. This eliminates the need for retraction mechanisms while maintaining aerodynamic continuity, as the spoiler remains stationary and properly positioned during both closed and open door operations.
Solution Approach 2:
The fixed structure upstream of the door serves as an intermediary carrier for the spoiler. Instead of integrating the spoiler into the moving door, it is mounted on the stationary fixed structure, which provides stable support and eliminates the need for complex retraction mechanisms.
2Productivity
If the door spoiler is made retractable, then the flow deflection is improved, but the reliability decreases due to potential mechanism failures
Solution Approach 1:
The retractable mechanism is completely removed by extracting the spoiler from the door assembly. The spoiler is repositioned on the fixed structure, providing reliable flow deflection without any moving parts that could fail.
Solution Approach 2:
The fixed structure with integrated spoiler automatically provides flow deflection functionality without requiring additional mechanisms or active control systems. The stationary design ensures reliable operation through passive aerodynamic guidance.
3Productivity
If flanks are added to cover the cavity sides, then the direct flow efficiency is improved, but the device complexity increases
Solution Approach 1:
The flanks are merged with the door structure itself, forming an integrated design where the flanks are structural components of the door rather than separate add-on elements. This provides aerodynamic benefits while minimizing additional complexity through unified construction.
Solution Approach 2:
The flanks serve multiple functions: they cover the cavity sides to improve aerodynamic continuity for direct flow, and they extend into the rebate to guide reverse flow during thrust reversal. This multi-functionality provides aerodynamic benefits without requiring separate dedicated components.
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 both direct thrust efficiency and reverse thrust braking performance while preventing damage to the turbojet engine by guiding flows effectively through the counter-thrust openings, improving aerodynamic continuity and reducing mechanical complexity.
Implementation Method 1
the flanks constitute simple, effective and economical means of both improving the passage of the forward flow by covering the cavity on the sides of the counter-thrust openings, and improving the passage of the reverse flow by guiding the gases on these sides of these openings
Implementation Method 2
This flow is first deflected by this inner surface which ends at the front end with a deflector comprising a spoiler forming a substantially right angle, in order to achieve a second deviation of the air flow allowing it to be projected as much as possible towards the front to obtain good braking efficiency
Implementation Method 3
when the door is closed, its inner surfaces must form for the annular stream of cold air the best possible aerodynamic continuity in order to facilitate the flow of this flow rearward, to give the turbojet engine the best propulsion efficiency
Data Source
Figure 1~3
Figure 4~7
AI summary
A turbojet engine nacelle comprising a thrust reversing device with doors, comprising inner walls on the sides of the opening. A turbojet engine nacelle comprising a thrust reversing device comprising doors (4) that swing to brake the direct gas flow, guiding it through counter-thrust openings (8), the inside of each door comprising, at the front, a cavity receiving a spoiler turned towards the front when this door is open, the fixed structure (2) upstream from each door (4) supporting a deflection edge (16) that partially covers the cavity, characterised in that the fixed structure (2) supports, on each side, counter-thrust openings (8), a flank (18) disposed in the continuation of the deflection edge (16) and extending behind the cavity, which is incorporated into a leaf of the door (4).