Fan Variable Area Nozzle for Gas Turbine Instability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional gas turbine engines with fixed geometry fan nozzles face challenges in maintaining stability and efficiency across varying flight conditions, particularly at low power and low flight speeds, due to their fixed geometry which can lead to fan instability and increased weight from complex variable area nozzle mechanisms.
Innovation Solution
A nacelle assembly for a high-bypass gas turbine engine featuring a fan variable area nozzle (VAFN) that is axially movable, allowing adjustment of the fan nozzle exit area and pressure ratio, driven by a gear system and controlled to reduce fan instability and optimize performance across different flight conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed geometry fan nozzle is used, then the device complexity is reduced, but the fan stability deteriorates under varying flight conditions
Solution Approach 1:
The patent applies the dynamics principle by implementing a variable area nozzle that can change its geometry during operation. The nozzle area is made adjustable through a control system that responds to flight conditions, allowing the fan nozzle to adapt its cross-sectional area to maintain optimal flow characteristics and stability across different operating regimes without requiring a completely complex mechanical mechanism.
Solution Approach 2:
The patent applies parameter changes by varying the nozzle exit area as a key geometric parameter. By adjusting the nozzle area parameter in response to changing flight conditions (such as Mach number and altitude), the system maintains stable fan operation without requiring complex mechanical reconfiguration mechanisms, thus resolving the contradiction between simplicity and stability.
2Stability of the object's composition
If a variable area fan nozzle is implemented, then the fan stability is improved, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing a control system that performs multiple functions: it monitors flight conditions, determines optimal nozzle area settings, and actuates the variable area mechanism. This multi-functional approach consolidates what could be multiple separate complex systems into a single integrated control architecture, improving fan stability while limiting the increase in overall device complexity.
Solution Approach 2:
The patent applies mechanics substitution by replacing complex mechanical variable area mechanisms with a more streamlined system. Instead of using elaborate mechanical linkages and actuators, the design employs a control system that can achieve nozzle area adjustment through simpler means, potentially using electronic control with minimal mechanical components, thus improving stability without proportionally increasing mechanical complexity.
3Use of energy by moving object
If a variable area nozzle mechanism is added, then the fuel efficiency is improved, but the weight increases
Solution Approach 1:
The patent applies the extraction principle by isolating and implementing only the essential components needed for variable area nozzle functionality. Rather than incorporating a complete, heavy mechanical variable geometry system, the design extracts and implements only the critical area-adjustment capability through a lighter-weight control mechanism, achieving fuel efficiency improvements while minimizing the weight penalty of the added system.
Data Source
AI summary
A nacelle assembly for a high-bypass gas turbine engine includes a fan variable area nozzle movable relative a fan nacelle to vary a fan nozzle exit area to reduce a fan instability.