Aircraft Nacelle Thrust Reverser with Axial Movable Part
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Solution Overview
Problem
Existing aircraft nacelle thrust reversal devices suffer from noise pollution issues due to untreated surfaces, aerodynamic losses, adjustment difficulties, and increased mass, as they compromise acoustic treatment and aerodynamic performance.
Innovation Solution
An aircraft nacelle design featuring a thrust reversal device with a movable part that translates to create a radial opening, equipped with a flap for flow deflection, and actuators positioned at reinforced zones to minimize structural reinforcement and weight increase, allowing for continuous acoustic treatment and optimized aerodynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a cascade thrust reverser with multiple flaps and connecting rods is used, then thrust reversal capability is achieved, but the internal surface area available for acoustic treatment coating is reduced and aerodynamic losses increase
Solution Approach 1:
The thrust reverser system is divided into modular units: a movable part that translates axially and fixed parts that remain stationary. This segmentation allows the movable part to be optimized for acoustic treatment continuity while the fixed parts provide structural support, reducing the overall number of joints requiring acoustic treatment exemptions.
Solution Approach 2:
The connecting rods and complex joint mechanisms traditionally required for flap actuation are extracted from the design. Instead, a simplified movable part translates axially to open radial openings, eliminating the need for numerous connecting elements and allowing continuous acoustic treatment coating on the internal surface.
2Device complexity
If the secondary duct is shaped to accommodate a translating movable part that contacts the inner wall, then the thrust reverser mechanism is simplified, but the aerodynamic performance of the propulsion assembly is reduced
Solution Approach 1:
The movable part is designed to translate dynamically along the axial direction only when thrust reversal is required. During normal operation, the movable part remains in its initial position, maintaining the original aerodynamic shape of the secondary duct and preserving propulsion assembly performance. This dynamic adjustment allows simplified mechanism design without permanent aerodynamic penalties.
3Object-generated harmful factors
If multiple pivoting elements and joint systems are added to the nacelle for thrust reversal, then the thrust reversal function is enabled, but the mass of the nacelle increases due to reinforcement requirements
Solution Approach 1:
The thrust reverser is segmented into a movable part and fixed parts, with the movable part handling the primary function of opening radial gaps. This segmentation eliminates the need for complex pivoting elements and extensive structural reinforcement, thereby reducing the overall mass of the nacelle while maintaining effective thrust reversal capability.
4Weight of moving object
If the movable part is positioned at reinforced zones with actuators, then structural reinforcement is minimized and weight increase is limited, but the complexity of actuator positioning and control increases
Solution Approach 1:
The movable part serves multiple functions: it acts as the primary thrust reversal element by translating to open radial openings, serves as a structural component positioned at reinforced zones to minimize additional reinforcement needs, and provides mounting points for actuators. This multi-functionality reduces overall system complexity despite the specialized positioning requirements.
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 effectively reduces noise pollution, maintains aerodynamic performance, and limits on-board weight by ensuring uninterrupted acoustic treatment and reducing the number of joints and obstacles within the nacelle.
Implementation Method 1
capable of occupying a first position in which the fixed part and the movable part are contiguous and a second position in which there is provided between the fixed part and the movable part a radial opening towards which at least part of the flow flowing in the secondary duct can be diverted
Data Source
Figure 1A~1C
Figure 2~4B
Figure 5~7
AI summary
The subject of the invention is an aircraft nacelle in which an engine is placed, and which delimits a conduit (16) through which a flow capable of contributing to the thrust can pass, said nacelle comprising a device for reducing, canceling out or reversing the thrust comprising at least one flap (34) capable of occupying at least one so-called active position in which it diverts, in the direction of a radial opening, at least part of the flow capable of contributing to the thrust and another so-called rest position in which said flap (34) does not interfere with the flow capable of contributing to the thrust, the wall of the nacelle delimiting the conduit through which the flow to be diverted passes comprising at least one moving part capable of occupying two positions, a first position in which it is interposed between the flow to be diverted and the flap (34) and another position in which it releases the flap (34) so as to allow said flap to change position and move from the rest position to the active position, characterized in that each flap (34) includes pivoting means (40) with a first pivot pin (42) placed at the level of a first so-called upper end of the flap (34) in the upper part of the nacelle and a second pivot pin (44) placed at the level of a second so-called lower end of the flap (34) in the lower part of the nacelle, said pivot pins (42, 44) being substantially parallel to the median vertical axis (26) of the nacelle.