Contra-Rotating Shaft Generator for Open-Rotor De-Icing Power
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Solution Overview
Problem
Existing de-icing systems for contra-rotating open rotor aircraft propulsion systems face challenges with power transfer, including mechanical wear, optical interference, fluid leakage, and high maintenance requirements due to slip ring assemblies, especially in contra-rotating systems where one slip ring is 'buried' within the shaft assembly.
Innovation Solution
An electrical power generation apparatus using counter-rotating shafts with windings and field arrays induces electrical current for de-icing elements on rotor blades, eliminating the need for mechanical, optical, fluid, or electrical connections between rotating parts, thereby providing power directly to de-icing apparatus without slip rings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If slip ring assemblies are used to transfer electrical power to rotating rotors, then power can be delivered to de-icing elements, but maintenance requirements increase due to brush wear and arcing failures
Solution Approach 1:
The patent extracts the de-icing power requirement from the rotating rotor system and relocates it to the stationary airframe. By using a contra-rotating shaft as the generator rotor, the system generates electrical power at the stationary end, eliminating the need for slip rings and brush assemblies that would otherwise be required to supply power to rotating components.
Solution Approach 2:
Instead of supplying electrical power to rotating rotors through slip rings (traditional approach), the invention inverts the approach by using the contra-rotating motion to generate electrical power at the stationary end. The generator produces power where it can be easily accessed and distributed, reversing the conventional power flow direction.
2Power
If sequential slip rings are used to power distal rotors in contra-rotating systems, then power reaches all rotors, but power transfer efficiency decreases and failure probability increases
Solution Approach 1:
The patent segments the power generation function by using the contra-rotating shaft itself as the generator rotor, creating independent electromagnetic fields for each rotor system. This segmentation allows each rotor to have its own dedicated power generation path without requiring sequential slip ring connections, thereby improving reliability and efficiency.
Solution Approach 2:
The contra-rotating shaft acts as an intermediary that converts mechanical contra-rotation directly into electrical power. This intermediary mechanism eliminates the need for multiple slip ring stages by serving as both the mechanical input and electrical output interface, simplifying the power transfer path and reducing failure points.
3Power
If mechanical power transfer is used between rotating components, then power can be transmitted, but wear, binding, and friction increase
Solution Approach 1:
The patent replaces mechanical power transmission mechanisms (gears, belts, direct shaft connections) with electromagnetic power generation. By using electromagnetic induction between the contra-rotating shaft and stator windings, power is transmitted without mechanical contact, eliminating wear, binding, and friction associated with traditional mechanical transmission systems.
4Power
If fluid power transfer is used along contra-rotating shafts, then power reaches rotating components, but complex seals and fluid passages are required that are susceptible to wear and leakage
Solution Approach 1:
The invention replaces fluid power transfer systems (hydraulic or pneumatic) with direct electromagnetic power generation. By generating electricity at the stationary end through contra-rotating electromagnetic induction, the system eliminates the need for complex fluid passages, seals, and pressure management systems that would be required to deliver hydraulic power to rotating components.
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 reduces maintenance needs, enhances efficiency, and ensures reliable power transfer to de-icing elements on contra-rotating rotors by leveraging contra-rotation to generate power within the same rotational frames, eliminating the need for slip rings and associated maintenance issues.
Implementation Method 1
Relative rotation of the first and second shafts induces an electrical current in the winding to power the electrical load
Data Source
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AI summary
An electrical power generation apparatus is embedded in a contra- rotating propulsion system that includes overlapping first and second shafts operatively connected for counter-rotation about a common axis. The electrical power generation apparatus includes a winding mounted to one of the shafts and a field array mounted to the other of the shafts adjacent to the winding. Relative rotation of the winding and the field array induces electrical current in the winding.