Variable Area Nozzle with Fixed-Ring Support for Drag Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing variable area nozzle assemblies for aircraft gas turbine engines face challenges in maintaining efficient operation across varying flight conditions and aircraft designs, particularly in terms of structural stability, aerodynamic drag, and thrust reverser door configurations.
Innovation Solution
A variable area nozzle assembly with a fixed ring and actuation system that provides structural support, minimizes aerodynamic drag, and allows for flexible orientation relative to aircraft body structures, incorporating a fixed ring that supports nozzle petals and thrust reverser doors to maintain stability and reduce drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable area nozzle assembly is designed to accommodate different flight conditions, then the adaptability is improved, but the device complexity increases due to multiple moving parts and actuation systems
Solution Approach 1:
The nozzle is divided into multiple petals that can independently move relative to each other, allowing the nozzle area to be varied in a stepwise manner. This segmentation enables adaptability to different flight conditions while keeping each individual petal structurally simple and easy to control.
2Device complexity
If thrust reverser doors are positioned close to the nozzle for compact design, then the device complexity is reduced, but aerodynamic drag increases due to interference with exhaust flow
Solution Approach 1:
The thrust reverser doors are positioned in the axial direction away from the nozzle, utilizing the axial dimension to resolve the conflict between compact radial design and aerodynamic performance. This axial spacing eliminates drag interference while maintaining overall compactness through optimized door geometry.
3Stability of the object's composition
If the nozzle is designed with a fixed ring structure for stability, then structural stability is improved, but aerodynamic drag increases due to the ring interfering with exhaust flow
Solution Approach 1:
The fixed ring is designed as a thin-walled structure that provides necessary structural stability while minimizing aerodynamic interference. The thin-walled design allows exhaust flow to pass through or around the ring with reduced drag, maintaining both structural integrity and aerodynamic efficiency.
4Stability of the object's composition
If the nozzle structure is made robust for stability, then structural stability is improved, but weight increases
Solution Approach 1:
The thin-walled fixed ring structure provides adequate structural stability with minimal weight. The design optimizes wall thickness to achieve the necessary strength and stiffness while keeping the weight as low as possible, avoiding over-engineering the structure.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A variable area nozzle assembly (54) for a gas turbine engine (20) includes a nozzle (60) disposed about a nozzle centerline (146) and a fixed ring (82) radially surrounding the nozzle (60). The nozzle (60) includes a radially outer surface (64) and a radially inner surface (68). The radially inner surface (68) defines an outlet cross-sectional area (78) of the nozzle (60). The nozzle (60) is movable relative to the nozzle centerline (146) between a first position of the radially inner surface (68) defining a maximum area of the outlet cross-sectional area (78) and a second position of the radially inner surface (68) defining a minimum area of the outlet cross-sectional area (78). With the nozzle (60) in the first position, the radially outer surface (64) contacts the fixed ring (82). With the nozzle in the second position, the radially outer surface is spaced from the fixed ring.