Coaxial Fan Electrical Machine C-Shaped Stator Integration
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Solution Overview
Problem
The integration of a high-power electric machine on the low-pressure body of an aircraft turbomachine is complex due to mechanical integration, temperature resistance, and accessibility issues, particularly in high dilution rate architectures.
Innovation Solution
A fan module design where the electric machine is mounted coaxially downstream of the fan with a rotor coupled in rotation, featuring an annular member with a C-shaped axial section, a radially external stator, and a radially internal support for guide bearings, optimized for low temperatures and air-cooled operation, allowing for significant power production and flexibility through a connecting element with torsional flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electric machine is integrated on the low-pressure body of the turbomachine, then the power production capability is improved, but the mechanical integration complexity and temperature resistance issues worsen
Solution Approach 1:
The electric machine is segmented into distinct functional components: a rotor coupled in rotation with the fan, a stator formed by the radially external part of the annular member, and a support structure formed by the radially internal part. This segmentation allows each component to be optimized independently for its specific function while simplifying the overall integration into the turbomachine architecture.
Solution Approach 2:
The electric machine is nested within the annular space downstream of the fan, with the rotor positioned coaxially within the annular member. The radially internal part of the annular member contains the guide bearings, creating a nested configuration where multiple functional elements are integrated within a compact annular volume, reducing overall complexity.
2Power
If the electric machine is integrated on the low-pressure body, then power production is improved, but temperature resistance and accessibility issues worsen
Solution Approach 1:
The annular member is designed with differentiated local qualities: the radially external part forms the stator exposed to the aerodynamic flow for cooling, while the radially internal part forms the support for guide bearings protected from direct flow exposure. This local differentiation optimizes each region for its specific requirements - cooling for the stator and protection for the bearings.
Solution Approach 2:
The electric machine utilizes the aerodynamic flow from the fan for self-cooling. The stator, being exposed to the flow, passively receives cooling without requiring additional active cooling systems. The machine's own operational flow serves the dual purpose of driving the rotor and cooling the stator.
3Temperature
If the electric machine is mounted downstream of the fan with C-shaped annular member, then cooling efficiency is improved, but mechanical stress and integration complexity increase
Solution Approach 1:
The connecting element between the rotor and fan is designed with torsional flexibility, allowing dynamic adaptation to operational variations. This flexible connection absorbs mechanical stresses and torques generated during operation, preventing stress concentration and fatigue while maintaining the beneficial cooling configuration.
4Duration of action of moving object
If the rotor is coupled in rotation with the fan at low speed, then service life is improved, but power production capability decreases
Solution Approach 1:
The electric machine parameters are optimized for low-speed operation: the rotor is designed with a relatively large diameter to maintain adequate power production at reduced rotational speeds. The magnetic circuit and winding configurations are tailored to generate sufficient torque and power at the lower speeds imposed by the fan coupling, while the reduced speed inherently extends service life by decreasing mechanical fatigue and wear.
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 design enhances the mechanical integration and cooling of the electric machine, enabling efficient power production while minimizing mechanical stress and optimizing temperature conditions, resulting in improved reliability and performance compared to previous technologies.
Implementation Method 1
an electric machine is an electromechanical device based on electromagnetism allowing the conversion of electrical energy, for example, into work or mechanical energy
Implementation Method 2
the machine is cooled by air flows, which optimizes the service life of the machine
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
A fan module for an aircraft turbine engine (10), this module comprising a fan (14) and an electrical machine (62), such that the electrical machine is coaxially mounted downstream of the fan and comprises a rotor (62a) coupled to rotate with the fan and an annular member (78) with generally C-shaped axial cross-section, the opening of which is axially orientated and receives the rotor (62a), this member comprising a radially outer portion (78a) forming a stator (62b), and a radially inner portion (78b) forming a support for bearings (80, 82) guiding the rotor (62a).