Variable Area Fan Nozzle Power Distribution
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Solution Overview
Problem
Gas turbine propulsion systems in rotorcrafts face limitations due to the need for secondary propulsion systems that reduce primary propulsion power and are mechanically coupled, limiting flexibility in power distribution between primary and secondary systems.
Innovation Solution
A convertible gas turbine propulsion system with a retractable port and exhaust system that allows selective control of combustion gas flow, enabling power distribution between a rotor system and a secondary propulsion system by coupling and uncoupling power turbines, and using a pneumatic actuator to adjust power distribution based on operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mechanical clutch coupling is used to connect the secondary propulsion system with the primary propulsion system, then the secondary propulsion system can be engaged, but the flexibility in power distribution is limited and the system complexity increases
Solution Approach 1:
The patent replaces the mechanical clutch coupling system with a pneumatic actuation system that uses compressed air to control the engagement and disengagement of the secondary propulsion system. This substitution eliminates complex mechanical linkages and provides more flexible, reliable control through pneumatic pressure regulation, directly resolving the contradiction between adaptability and device complexity
Solution Approach 2:
The invention employs a pneumatic actuator that uses compressed air from the gas turbine engine to drive the engagement and disengagement of the secondary propulsion system. The pneumatic system provides precise control over power distribution by regulating air pressure, enabling flexible operation without the mechanical complexity of traditional clutch systems
2Ease of operation
If the secondary propulsion system is mechanically coupled to the free shaft, then additional thrust can be produced, but the secondary propulsion system must rotate at speeds dictated by the free shaft, reducing operational independence
Solution Approach 1:
The patent segments the power transmission system by introducing a pneumatic actuator that operates independently from the mechanical free shaft coupling. This allows the secondary propulsion system to be controlled separately through pneumatic pressure regulation, enabling independent operation while maintaining the ability to produce additional thrust when needed
3Adaptability or versatility
If a retractable port is used to control combustion gas flow, then power distribution between rotor system and secondary propulsion system can be adjusted, but the device complexity increases
Solution Approach 1:
The retractable port mechanism serves multiple functions: it controls combustion gas flow distribution, actuates the pneumatic actuator for engagement/disengagement, and regulates power distribution between the rotor system and secondary propulsion system. This multi-functionality reduces the need for separate control mechanisms, thereby limiting the increase in device complexity while maximizing adaptability
Data Source
AI summary
A rotary-wing aircraft includes a retractable port movable between a closed position and an open position to selectively control flow of combustion gases into a bypass passage to change a power distribution between a rotor system and a secondary propulsion system.