Turbofan Thrust Reverser Iris Mechanism for Weight Reduction
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Solution Overview
Problem
Existing turbofan propulsion systems with thrust reverser systems are heavy, expensive, require frequent maintenance, and cause aerodynamic discontinuities due to numerous movable components, and occupy significant space, making maintenance inconvenient and slow, especially when the bypass duct has an O or ring cross section.
Innovation Solution
A turbofan propulsion system incorporating a thrust reverser system with a movable iris mechanism that occludes the air passage and a coordinated actuator system to minimize airflow leakage, reduce noise, and facilitate maintenance by allowing the translating and fixed structures to be easily opened for inspection, using a radial opening and iris mechanism for thrust reversal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional blocker doors and rods are used for thrust reversal, then thrust reversal function is achieved, but the system becomes heavy and complex with frequent maintenance requirements
Solution Approach 1:
The patent removes the complex rod mechanism and multiple blocker doors from the traditional thrust reverser system. Instead, it uses a single movable structure with an iris mechanism that can be extracted or removed entirely when not in use, significantly reducing the number of movable components and maintenance requirements while preserving the thrust reversal function.
Solution Approach 2:
The movable structure serves multiple functions: it acts as both the thrust reverser mechanism and a protective cover for the engine inlet. The iris mechanism within it provides both occlusion for thrust reversal and aerodynamic sealing. This multi-functionality reduces the overall system complexity by eliminating separate components.
2Reliability
If multiple movable components are arranged inside the outflow duct, then thrust reversal is achieved, but maintenance becomes inconvenient and slow
Solution Approach 1:
The thrust reverser system is segmented into a movable structure that can be independently removed from the engine assembly. This segmentation allows maintenance personnel to access and service the movable structure separately without disassembling the entire engine, significantly improving maintenance accessibility and reducing downtime.
Solution Approach 2:
The movable structure with the iris mechanism can be completely extracted from the engine inlet area for maintenance. This extraction capability allows easy inspection and repair of the thrust reversal components without requiring complex disassembly procedures, directly addressing the maintenance accessibility problem.
3Force
If blocker doors are used to occlude air passage, then thrust reversal is provided, but aerodynamic discontinuities and noise are generated
Solution Approach 1:
The iris mechanism provides dynamic occlusion of the air passage, allowing gradual adjustment of the opening area rather than abrupt blocking. This dynamic control smooths the aerodynamic flow transition, reducing discontinuities and associated noise while maintaining the required thrust reversal force through controlled flow redirection.
Solution Approach 2:
The system changes the parameter of air passage occlusion from a binary state (blocked/not blocked) to a continuous variable (opening area). By varying the opening area of the iris mechanism, the system achieves smooth aerodynamic transitions that reduce noise and discontinuities while maintaining effective thrust reversal through optimized flow management.
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 the weight and complexity of the thrust reverser system, minimizes airflow leakage, decreases noise emissions, and simplifies maintenance by reducing the number of components and aerodynamic discontinuities, while enabling efficient thrust reversal and easy inspection of the structures.
Implementation Method 1
an iris mechanism (190), adapted to occlude at least partially the bypass duct (430)
Data Source
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AI summary
The turbofan propulsion system (30) comprises: a core engine (200); an engine nacelle (40), around the core engine (200), and comprising a front portion of the engine nacelle (50); a bypass duct (430), between the core engine (200) and the engine nacelle (40); a thrust reverser system (60) arranged downstream the front portion of the engine nacelle (50) of the engine nacelle (40), and the fixed structure (80) of the thrust reverser system (60) being arranged connected to said front portion of the engine nacelle (50); the thrust reverser system (60) comprising: a fixed structure (80) and a translating structure (90) arranged slidable along an axial direction (10) between a stowed position, wherein the translating structure (90) is sealingly connected to said fixed structure (80), and an open position, wherein the translating structure (90) is spaced apart from said fixed structure (80) so as to define a circumferential opening (12) between said translating structure (90) and said fixed structure (80), said opening (12) being adapted to allow the outflow of air towards the external environment; an iris mechanism (190), comprising a plurality of blades (140) jointly movable between a rest configuration, wherein they jointly define a passage for air, and a deployed configuration wherein said plurality of blades (140) is adapted to at least partially occlude said passage; a pylon (20), adapted to support said turbofan propulsion system (30) by connecting said engine nacelle (40) to a wing of said aircraft; a pylon coupling system (160) adapted to suspend the thrust reverser system (60) to the pylon (20) and to allow a translation movement of the translating structure (90); wherein the iris mechanism (190) is permanently constrained to the pylon coupling system (160) and is adapted to be connected to the translating structure (90) for translation with the latter.