Rotating Blades for Turbofan Secondary Flow Deflection
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Solution Overview
Problem
Existing turbofan engines with reversing doors are heavy and obstruct the secondary flow when in the retracted position, necessitating a lighter and obstruction-free mechanism for deflecting the secondary flow.
Innovation Solution
A dual-flow turbofan engine design featuring rotatable blades mounted on a slider, with an operating system that moves the blades between retracted and deployed positions to deflect the secondary flow, replacing traditional reversing doors and their mechanisms with lighter pivoting blades and a simplified maneuvering system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If traditional reversing doors and their drive mechanisms are used, then effective secondary flow deflection is achieved, but the device becomes heavy and obstructs the secondary flow in the retracted position
Solution Approach 1:
The patent extracts and removes the heavy reversing doors and their complex drive mechanisms from the system. Instead, it uses a series of lightweight blades that can be individually positioned to achieve the same flow deflection function without the weight and complexity of traditional reversing mechanisms.
Solution Approach 2:
The patent divides the continuous reversing door into multiple discrete blades that can be independently controlled. Each blade can be positioned separately to achieve precise flow management, and when retracted, they are distributed around the circumference rather than forming a single obstructive structure.
2Ease of operation
If reversing doors are used to deflect secondary flow, then back pressure is produced, but the connecting rod obstructs the secondary flow in the retracted position
Solution Approach 1:
The patent employs dynamically adjustable blades that can change their position and orientation based on operational requirements. When deflection is needed, blades rotate into position; when not needed, they retract to minimal obstruction positions, providing dynamic adaptability without persistent flow blockage.
Solution Approach 2:
The patent moves the blocking function from a two-dimensional plane (reversing doors blocking the flow path) to a three-dimensional arrangement where blades can rotate out of the primary flow path while still effectively deflecting flow when needed, utilizing the radial dimension for retraction.
Data Source
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AI summary
A turbofan engine (100) with a nacelle (102) includes a slide (218) movable in translation between an advanced position and a retracted position to open a window between a duct and the outside, a plurality of blades (250), each movable in rotation on the slide (218) between a retracted position and a deployed position, and a maneuvering system (400) moving each blade (250) and comprising, for each blade (250), a shaft (402 movable in rotation on the slide (218) and on which the blade (250) is fixed, an arm (414) having a first end fixed to the shaft (402) and a second end, an arc (408) coaxial with the longitudinal axis, mounted movable in rotation on the slide (218) about the longitudinal axis, a lever (406) mounted articulated between the arc (408) and the second end of the arm (414), and an actuation system which performs the rotation of the arc (408) in one direction and in the other.The use of rotating blades on the slide and the simplified operating system allows for a reduction in overall weight compared to the use of state-of-the-art reversing doors.