Multiflow Turbojet Engine Suspension with Rigid Pylon Attachment
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Solution Overview
Problem
The current attachment methods for multi-flow turbojet engines become less suitable as the bypass ratio increases, leading to greater loads and deformations during takeoff, causing bending and misalignment issues that reduce engine performance, with existing solutions failing to adequately address these issues.
Innovation Solution
A statically indeterminate suspension system with a rigid connection between the intermediate casing and the pylon, featuring an actuator that compensates for exhaust casing diameter variations to maintain coaxiality between the fan and turbine shafts, using sensors to adjust the distance between the exhaust casing and the pylon based on measured deformations and thermal expansions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bypass ratio is increased to improve engine efficiency, then engine performance is improved, but the loads and deformations during takeoff increase causing bending and misalignment
Solution Approach 1:
The suspension system transitions from a static determinate structure to a static indeterminate structure with rigid connections, allowing the system to dynamically adapt to varying load conditions. The redundant rigid connections enable the structure to redistribute stresses and maintain rigidity under high bypass ratio conditions.
Solution Approach 2:
The invention changes the structural parameters of the suspension system by introducing rigid connections between the engine casing and pylon, transforming the mechanical properties of the attachment system to withstand increased loads from high bypass ratio engines.
2Power
If the fan diameter is increased to achieve higher bypass ratio, then thrust is improved, but the central part remains flexible causing deformations and misalignment
Solution Approach 1:
The static indeterminate suspension system with rigid connections provides dynamic stability to the engine assembly, preventing misalignment of rotary elements during operation while accommodating the larger fan diameter required for high bypass ratio.
Solution Approach 2:
The rigid connections act as intermediary structural elements between the engine casing and pylon, transmitting and distributing loads to prevent deformations that would cause misalignment of the fan and turbine shafts.
3Device complexity
If the current attachment means are used for high bypass ratio engines, then simplicity is maintained, but load transmission is insufficient during takeoff
Solution Approach 1:
The suspension system evolves from a simple static determinate structure to a more complex static indeterminate structure with rigid connections, enabling enhanced load transmission capability while maintaining operational simplicity through automated load distribution.
Solution Approach 2:
The attachment system is segmented into multiple rigid connection points along the pylon length, distributing the load transmission function across several structural interfaces to handle the increased forces from high bypass ratio engines during takeoff.
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 solution effectively transmits loads and compensates for deformations, maintaining coaxiality and reducing bending-related losses, thereby enhancing engine performance and stability across various flight phases.
Implementation Method 1
a means for compensating for the variations in diameter of the exhaust casing so as to keep the axis of the exhaust casing coaxial with the axis of the intermediate casing through the various phases of flight of the aircraft
Data Source
AI summary
A suspension of a multi-flow turbojet engine provided with an intermediate casing and an exhaust casing from a pylon that can be attached to the structure of an aircraft is disclosed. The suspension includes a forward attachment device between the hub of the intermediate casing and the pylon, a rear attachment device between the exhaust casing and the pylon, and a connection device rigidly connecting the intermediate casing to the pylon. The rear attachment device includes an actuator for compensating for the variations in diameter of the exhaust casing so as to keep the axis of the exhaust casing coaxial with the axis of the intermediate casing through the various phases of flight of the aircraft.