Rotatable Blade Thrust Reverser for Turbofan Weight Reduction
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Solution Overview
Problem
Existing bypass turbojet systems rely on heavy reversing doors for thrust reversal, which can be cumbersome and heavy, limiting their efficiency and mass reduction potential.
Innovation Solution
Adaptation of an iris-type thrust reverser mechanism, where rotatable blades are used instead of traditional reversing doors, allowing for lighter and more efficient diversion of secondary flow to achieve counter thrust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional reversing doors are used for thrust reversal, then effective thrust reversal is achieved, but the system mass increases
Solution Approach 1:
The secondary flow stream is divided into multiple discrete streams by individual rotatable strips positioned at different radial locations. Each strip independently blocks and redirects a portion of the secondary flow, collectively achieving complete thrust reversal without requiring a single large heavy door structure
Solution Approach 2:
The rotatable strips are mounted on rotating spools that can dynamically adjust the blocking position and extent of each strip. This dynamic control allows the system to achieve thrust reversal on demand while maintaining a lightweight configuration during normal flight operations when the strips remain retracted
2Weight of moving object
If rotatable blades are used instead of reversing doors, then system mass is reduced, but the mechanism complexity increases
Solution Approach 1:
Multiple rotatable strips are integrated onto a common rotating spool structure, allowing them to be actuated simultaneously by a single drive mechanism. This merging of multiple control elements into one unified rotating assembly reduces the overall number of independent actuators and simplifies the control system compared to having separate mechanisms for each strip
Solution Approach 2:
The rotating spool structure serves multiple functions: it acts as the mounting support for the strips, provides the rotational actuation mechanism, and functions as part of the flow blocking structure itself. This multi-functionality reduces the need for additional separate components, thereby reducing overall system complexity despite the innovative blade configuration
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 use of rotatable blades in the iris-type mechanism reduces the overall mass of the system while maintaining effective thrust reversal capabilities, enhancing the aircraft's performance and efficiency.
Implementation Method 1
a series of blades (250) which are mounted so as to be able to rotate on the slider (218) from a retracted position in which they are outside the vein (204) to a position in which they are across the vein (204) in order to block it and divert the air flow towards the front of the turbojet (100)
Data Source
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AI summary
The invention relates to a turbofan engine (100) with a fan casing (202) and a nacelle (102) comprising a fixed structure (206), a movable assembly (214) with a movable cowl (216) and a slide (218), movable in translation between an advanced position and a retracted position in which the movable cowl (216) is moved away from the fan casing (202) to define a window (220) open between a duct (204) and the outside of the nacelle (102), a plurality of blades (250), each being mounted for rotation on the slide (218), where each blade (250) is movable between a retracted position in which the blade (250) is outside the duct (204) and a deployed position in which the blade (250) is across the duct (204), a set of actuators (222) ensuring the movement of the slide (218) and a maneuvering system for moving each blade (250) from the retracted position to the deployed position and vice versa.The use of rotating blades (250) on the slide (218) allows for a reduction in the overall weight compared to the use of reversing doors in the prior art.