Variable Area Fan Nozzle Ring Assembly for Bypass Flow Control
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Solution Overview
Problem
Existing variable area nozzle systems for aircraft turbofan engines are complex, heavy, and inefficient, leading to increased fuel consumption and noise due to undesirable leakage and drag, while struggling to optimize engine performance across varying flight conditions.
Innovation Solution
A translating ring assembly at the rear of the engine nacelle varies the nozzle exit area by moving fore and aft, creating an upstream exit to bleed excess flow, thereby optimizing engine operation and reducing fan pressure ratios for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional variable area nozzle systems use multiple flow deflectors or fins that pivot to vary nozzle area, then the nozzle exit area can be adjusted to optimize engine performance, but the system becomes complex, heavy, and causes undesirable leakage and drag
Solution Approach 1:
The nozzle is divided into a fixed forward portion and a movable rear portion (ring assembly), allowing independent control of each section to achieve area variation without complex multi-component systems
Solution Approach 2:
The invention extracts the essential function of area adjustment from the complex system of multiple pivoting deflectors and simplifies it to a single translating ring assembly that moves linearly to achieve the same goal
2Manufacturing precision
If traditional variable area nozzle systems use multiple components with complicated drive mechanisms, then precise control of nozzle area is achieved, but the system becomes heavy and expensive
Solution Approach 1:
Multiple control functions are merged into a single translating ring assembly that simultaneously controls the nozzle area and creates the upstream exit, eliminating the need for separate heavy components and drive mechanisms
Solution Approach 2:
The translating ring assembly performs multiple functions: it adjusts the downstream nozzle exit area and simultaneously creates the upstream exit for bypass flow, reducing the overall system complexity and weight
3Use of energy by moving object
If turkey feathers expand to increase nozzle opening, then exhaust flow area is increased to lower FPR, but leakage and drag increase causing greater fuel consumption
Solution Approach 1:
The translating ring assembly acts as an intermediary that smoothly transitions between closed and open positions, creating controlled upstream exit that prevents the abrupt flow separation and turbulence caused by traditional turkey feather expansion
Solution Approach 2:
The system changes the geometric parameters of the nozzle by translating the ring assembly along the axial direction, varying the exit area and creating upstream exit to optimize flow characteristics and reduce energy losses
Data Source
AI summary
The exit area of a nozzle assembly is varied by translating a ring assembly located at a rear of the engine nacelle. The ring may be axially translatable along the axis of the engine. As the ring translates, the trailing edge of the ring defines a variable nozzle exit area. Translation of the ring creates an upstream exit at a leading edge of the ring assembly. The upstream exit can be used to bleed or otherwise spill flow excess from the engine bypass duct. As the engine operates in various flight conditions, the ring can be translated to obtain lower fan pressure ratios and thereby increase the efficiency of the engine. Fairings partially enclose actuator components for reduced drag.