Aircraft Engine Attachment Strut Axial Positioning
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Solution Overview
Problem
Existing dual-flow turbojet attachment struts are heavy, bulky, and protrude radially, leading to aerodynamic losses and reduced performance due to insufficient ground clearance, which complicates installation under aircraft wings and hinders access to critical engine components.
Innovation Solution
A dual-flow turbomachine with a primary and secondary structural case arrangement that positions the attachment strut close to the engine axis, incorporating a thrust reversal system and connecting rods or springs, allowing for compact assembly and reduced dimensions, enabling efficient force transmission and ground clearance preservation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the attachment strut extends radially towards the outside at a substantial distance from the engine axis, then the structural strength and force transmission capability are improved, but the overall mass and bulkiness of the strut increase
Solution Approach 1:
The patent repositions the attachment strut from a radial extension to an axial positioning downstream of the combustion chamber, changing the spatial dimension of force transmission. This allows the strut to maintain structural strength while reducing radial protrusion and overall mass.
Solution Approach 2:
The attachment function is extracted from the traditional radial strut structure and relocated to a compact axial position. The strut is separated from the bulky radial configuration and repositioned to achieve the same force transmission function with reduced mass.
2Adaptability or versatility
If the attachment strut protrudes radially towards the outside and upwards relative to the fan casing, then the mounting flexibility is improved, but aerodynamic losses increase and ground clearance is reduced
Solution Approach 1:
The strut positioning moves from radial-protruding configuration to axial-downstream configuration, changing the spatial arrangement to eliminate aerodynamic interference while maintaining mounting capability.
Solution Approach 2:
The combustion chamber downstream area, which could be considered a harmful or unused zone, is utilized for strut attachment. This converts a potentially harmful area into a beneficial mounting location that improves aerodynamics while maintaining flexibility.
3Device complexity
If the attachment strut is positioned in alignment with the combustion chamber, then the structural compactness is improved, but the risk of damage from released flames increases
Solution Approach 1:
The patent positions the strut downstream of the combustion chamber, using the combustion chamber outlet as an intermediary boundary. This allows the strut to be close to the combustion chamber for compactness while being protected from direct flame exposure by the chamber structure itself.
4Length of moving object
If the primary structure extends radially towards the outside, then the force transmission path is shortened, but the bending of the turbomachine in the transverse direction increases
Solution Approach 1:
The force transmission is redirected from radial to axial dimension by positioning the strut downstream of the combustion chamber. This changes the orientation of the force path to align with the turbomachine axis, reducing transverse bending while maintaining transmission efficiency.
Data Source
AI summary
An engine assembly for an aircraft including a dual-flow turbomachine and an attachment strut. The turbomachine includes a structural case extending downstream of the hub of an intermediate casing, the case contributing to the internal radial delimitation of a passage for a secondary flow of the turbomachine. Also, the primary structure includes a structural case, assembled on the structural case and positioned directly downstream of the structural case such that it also contributes to the internal radial delimitation of the passage for the secondary flow. The primary structure also includes an offset structure positioned in the passage, and configured to connect the case to an element of the aircraft. The structural case also includes a thrust reversal system.