Variable Area Fan Nozzle Control for Gas Turbine Engines
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Solution Overview
Problem
Gas turbine engine fan operability is compromised by fixed nozzle area designs, leading to inefficiencies and performance penalties across varying flight conditions, as they struggle to maintain adequate margin against conditions like fan flutter, surge, or stall.
Innovation Solution
A method is implemented to adjust the variable area fan nozzle position based on detected airspeed and fan speed, using a parameter relationship to determine a target position and adjust the nozzle exit area, thereby optimizing fan operability and performance across different flight conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed nozzle area design is used, then the engine structure is simple and easy to manufacture, but the fan operability is compromised and performance is reduced across varying flight conditions
Solution Approach 1:
The patent applies the dynamics principle by transforming the fixed nozzle structure into a variable area nozzle that can dynamically adjust its exit area based on flight conditions. The nozzle includes movable flaps that can change position to vary the exit area, allowing the engine to optimize performance across different operating conditions while maintaining adequate fan operability margin.
2Device complexity
If a fixed nozzle area design is used, then the device complexity is low, but the adaptability to different flight conditions is reduced
Solution Approach 1:
The nozzle system transitions from a static fixed-area design to a dynamic variable-area design with movable flaps controlled by an actuator system. This allows the nozzle to adapt to different flight conditions (airspeed, fan speed) while the control system uses parameter relationships and thresholds to manage the complexity of the adjustment process.
Solution Approach 2:
The control system implements feedback by continuously monitoring flight conditions (airspeed, fan speed) and comparing them against parameter relationships and thresholds. Based on this feedback, the system automatically adjusts the nozzle position to maintain optimal fan operability margin, creating a closed-loop control system that adapts to changing conditions.
3Adaptability or versatility
If the fan operating line is compromised to accommodate various engine operating conditions, then the engine can operate across the flight envelope, but fuel consumption increases
Solution Approach 1:
By implementing a variable area nozzle that dynamically adjusts exit area based on real-time flight conditions and fan speed, the system maintains optimal fan operability margin across all operating conditions. This eliminates the need to compromise the fan operating line, allowing the engine to achieve better fuel efficiency while still accommodating the full flight envelope.
Solution Approach 2:
The system changes the nozzle exit area parameter dynamically based on flight conditions (airspeed, fan speed) to optimize engine performance. By adjusting this physical parameter, the system maintains adequate fan operability margin across different operating conditions, improving fuel consumption characteristics without sacrificing adaptability.
Data Source
AI summary
A method of managing a gas turbine engine includes the steps of detecting an airspeed and detecting a fan speed. A parameter relationship is referenced related to a desired variable area fan nozzle position based upon at least airspeed and fan speed. The detected airspeed and detected fan speed is compared to the parameter relationship to determine a target variable area fan nozzle position. An actual variable area fan nozzle position is adjusted in response to the determination of the target area fan nozzle position and at least one threshold.