Variable-Pitch Fan Blades for Thrust and Power Generation
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Solution Overview
Problem
Aircraft propulsion systems face challenges in designing systems that can efficiently provide thrust and power for aircraft accessories across various flight conditions, often requiring compromises between thrust and power generation, especially at high altitude where power requirements are demanding.
Innovation Solution
The integration of a fan module with a fan rotor and a power supply system that includes variable-pitch fan blades, a torque transmitting device, a generator, and a controller, allowing the fan rotor to switch between thrust-generation and power-generation orientations based on flight conditions, enabling efficient thrust production when needed and power generation when thrust is low.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the fan rotor is driven by the rotational power source to produce thrust, then thrust generation is improved, but power generation capability deteriorates
Solution Approach 1:
The fan blade pitch angle is made dynamically adjustable through an actuator system. The controller modifies the pitch angle in real-time based on operational conditions, allowing the fan to transition between thrust-generation mode (higher pitch angles) and power-generation mode (lower pitch angles), thereby resolving the contradiction between thrust and power generation capabilities
Solution Approach 2:
The fan rotor is designed to perform multiple functions: it can operate as a thrust-generating propeller when driven by the rotational power source, and as a power-generating turbine when driven by ram air. This multi-functionality allows the same component to satisfy both thrust requirements and power requirements under different flight conditions
2Power
If the fan rotor is de-coupled from the rotational power source to allow ram air rotation for power generation, then power generation is improved, but thrust production deteriorates
Solution Approach 1:
The torque transmitting device provides dynamic coupling control, engaging to connect the fan rotor to the rotational power source for thrust production, and disengaging to allow independent ram air-driven rotation for power generation. This dynamic engagement/disengagement mechanism enables the system to switch between thrust and power generation modes effectively
3Adaptability or versatility
If variable-pitch fan blades are used to optimize both thrust and power generation, then system versatility is improved, but device complexity increases
Solution Approach 1:
The actuator mechanism is integrated with the fan blade structure, and the torque transmitting device is combined with the fan rotor assembly. This merging of functions reduces the number of separate components and simplifies the overall system architecture while maintaining the capability for variable pitch operation and mode switching
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for optimized thrust production during high-thrust conditions and efficient power generation during low-thrust conditions, addressing the challenge of meeting both thrust and power requirements without oversizing the propulsion system, and enabling the fan to act as a ram air turbine for charging accessories or power cells.
Implementation Method 1
a generator coupled to the fan rotor and configured to produce electrical power in response to a mechanical load applied by the fan rotor to the generator
Implementation Method 2
pressurized air discharged by the fan blades when the fan blades are in the thrust-generation orientation is generally directed along the central axis to produce thrust
Implementation Method 3
the fan rotor is free to rotate about the central axis and is aerodynamically optimized to rotate in response to ram air interacting with the fan rotor
Data Source
AI summary
A fan module for an aircraft is disclosed herein. The fan module includes a fan rotor and an optional power supply system. The fan rotor is mounted for rotation about a central axis and configured to couple to a rotational power source. The fan rotor includes a plurality of variable-pitch fan blades each movable from a thrust-generation orientation to a power-generation orientation.