Hybrid Compressor with Independent Electric Machine
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Solution Overview
Problem
Aircraft turbomachines of the twin-body, double-flow turbojet type face challenges in maintaining efficient gas flow across a wide operating speed range due to the phenomenon of pumping, which degrades aerodynamic flow quality and compressor performance, particularly in low-pressure compressors, where variable geometry solutions like VBV and RDE introduce inefficiencies and limited corrective capacities.
Innovation Solution
Incorporating an electrical machine downstream of the low-pressure compressor to rotate a ring of moving blades independently of the compressor rotor speed, allowing for improved airflow control and flexibility, with the electric machine's speed controlled to optimize aerodynamic operation and avoid pumping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If variable geometry systems (VBV, RDE) are integrated into the low-pressure compressor to control flow across wide speed ranges, then compressor operability is improved, but aerodynamic flow quality degrades due to clearance, slots, and leaks
Solution Approach 1:
The invention extracts the flow control function from the compressor itself and places it in a separate electric machine downstream. The electric machine's rotor, when rotated, generates a jet of air that mixes with the compressor discharge flow to control surge and pumping phenomena, eliminating the need for variable geometry components within the compressor that would compromise aerodynamic efficiency.
Solution Approach 2:
The electric machine acts as an intermediary between the compressor and the combustion chamber. By injecting controlled amounts of air through the electric machine's rotor, it mediates the flow control function, allowing the compressor to operate at optimal aerodynamic conditions while still preventing surge and pumping across the entire speed range.
2Adaptability or versatility
If variable geometry systems are added to control compressor flow, then operability across speed ranges is improved, but device complexity increases
Solution Approach 1:
The invention removes complex variable geometry mechanisms (VBV, RDE) from the compressor system and replaces them with a simpler electric machine. The electric machine, driven by the high-pressure turbine, provides flow control through rotor rotation without requiring moving parts or adjustable geometries within the compressor itself, thereby reducing overall system complexity.
3Productivity
If an electric machine is integrated to drive the low-pressure compressor rotor, then compressor performance is optimized in certain regimes, but high-pressure compressor operability degrades
Solution Approach 1:
The invention segments the power transmission system by placing the electric machine between the low-pressure compressor and the high-pressure compressor. The electric machine is driven by the high-pressure turbine and can independently control the low-pressure compressor's air flow, allowing optimized compressor performance without constraining the high-pressure compressor's operating range.
Solution Approach 2:
The electric machine serves as an intermediary that decouples the control of the low-pressure compressor from the high-pressure compressor. By controlling air flow through the electric machine's rotor, it allows the low-pressure compressor to operate optimally while the high-pressure compressor maintains its full operability range, eliminating the trade-off present in directly coupled systems.
4Adaptability or versatility
If the low-pressure compressor operates over a wide speed range (25% to 105% of nominal speed), then adaptability is improved, but pumping phenomena occur that degrade flow quality
Solution Approach 1:
The invention ensures continuous useful action by using the electric machine to maintain proper air flow through the low-pressure compressor across the entire speed range. The electric machine's rotor, when rotated, continuously generates mixing air that prevents surge and pumping phenomena, allowing the compressor to operate efficiently from 25% to 105% of nominal speed without loss of flow quality.
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 enhances airflow control and flexibility, reducing pumping phenomena and maintaining efficient operation across varying speeds, while also enabling airflow maintenance during engine stoppages for maintenance or cooling, thus improving overall turbomachine performance.
Implementation Method 1
the rotor of which drives in rotation a ring of moving blades configured to generate an air flow when it is set in rotation
Data Source
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AI summary
The invention relates to an aircraft turbine engine (101) which comprises, downstream of the low pressure compressor of its low pressure body (104) and upstream of its combustion chamber (102), an electric motor (206) which is configured to rotate a rotor blade ring so as to generate a flow of air. Moreover, the rotational speed of the electric machine rotor is independent of the rotational speed of the compressor rotor.