Gas Turbine Flow Reverser with Variable Nozzle Jet
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Solution Overview
Problem
Thrust reversers in gas turbine engines face challenges in efficiently controlling and directing exhaust flow for deceleration, particularly in creating a variable nozzle jet that minimizes flow reversal near critical areas like pylons and the ground to avoid debris ingestion and ensure smooth operation.
Innovation Solution
A gas turbine engine design featuring a flow reverser with translatable parts and profile edges that form a nozzle jet with varying width around the circumference, utilizing overlapping edges with bull nose and hook parts to create a seal and direct exhaust flow efficiently, and incorporating seal elements like inflatable parts or flaps to manage gap closure and flow direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blocker doors are used to reverse flow direction, then exhaust flow reversal is achieved, but device complexity increases and aerodynamic efficiency decreases due to discontinuous surfaces
Solution Approach 1:
The reverser is divided into multiple cascades arranged circumferentially, each cascade independently directing flow. This segmentation allows complex flow reversal functionality to be achieved through simpler, modular units that maintain aerodynamic continuity
Solution Approach 2:
The cascades serve multiple functions: they direct exhaust flow for reverse thrust, maintain contiguous aerodynamic surfaces, and enable flow control without requiring separate blocker doors. This multi-functionality reduces overall device complexity while achieving reliable flow reversal
2Power
If axial translation of the aft nacelle is used to open radial gaps, then reverse thrust is achieved, but the load-path becomes long and flexible requiring complex structural design
Solution Approach 1:
The reverser structure incorporates dynamic elements that allow controlled movement and deformation under load. The load-path is designed to flexibly accommodate axial translation while maintaining structural integrity, reducing the need for overly rigid and complex support structures
Solution Approach 2:
The load-path utilizes flexible structural elements and thin-walled components that can deform elastically to accommodate the long load-path requirements. This flexibility allows the structure to handle the extended load-path without requiring additional rigid bracing or complex reinforcement
3Ease of manufacture
If the nozzle jet width is uniform around the circumference, then manufacturing is simplified, but flow control near critical areas like pylons and ground is insufficient
Solution Approach 1:
The nozzle jet width is varied locally around the circumference, with narrower sections positioned near critical areas such as pylons and ground contact zones. This local variation maintains simple overall manufacturing while providing targeted flow control to minimize debris ingestion in specific hazardous regions
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 design effectively reverses thrust while minimizing flow reversal near critical areas, reducing debris ingestion and optimizing thrust distribution, ensuring efficient deceleration and reduced structural loads on the engine.
Implementation Method 1
the seal elements include an inflatable part or flap or iris-type mechanism to close any gap between the reverser part and the core
Data Source
AI summary
A flow reverser comprising a sleeve having a first part and a second part to define a flow path and axially separable from each other about a conjunction formed by a respective profile edges for the first part and the second part, the profile edges in a stowed position overlapping, the reverser characterised in that in a deployed position a nozzle part of each profile edge define together a nozzle jet and a reverser part of one edge profile is adjacent to a core to provide an effective flow deflector.