Aircraft Engine Transient Control via Electrical Power Transfer
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Solution Overview
Problem
Aircraft engines face operability challenges during transient operating conditions, such as acceleration and deceleration, due to high inertia of high-pressure spools relative to power output, which can affect efficiency and performance.
Innovation Solution
The integration of an electrical system that includes an electric machine and power unit, allowing for the transfer of power between the engine's high-pressure spool and external power sources or loads, enabling the absorption of transient conditions through power injection or withdrawal, managed by a Full Authority Digital Engine Control (FADEC) system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If aircraft engines are designed for high efficiency during cruise phase, then fuel efficiency is improved, but operability during transient conditions deteriorates due to high inertia of high-pressure spools
Solution Approach 1:
An electric machine is introduced as an intermediary between the high-pressure spool and the power output system. This electric machine can independently adjust the rotational speed of the high-pressure spool during transient conditions, decoupling it from the direct mechanical coupling that causes inertia problems. The electric machine acts as a mediator that allows the high-pressure spool to operate efficiently during cruise while enabling flexible speed control during transients.
2Stability of the object's composition
If the high-pressure spool has high inertia relative to power output, then structural stability is improved, but transient response deteriorates
Solution Approach 1:
The patent replaces part of the direct mechanical coupling system with an electric machine that provides controlled mechanical power. Instead of relying solely on mechanical inertia for stability, the electric machine uses electromagnetic control to manage the high-pressure spool's rotational speed during transients, substituting mechanical inertia-based stability with controlled electromagnetic torque.
3Speed
If power is transferred between the high-pressure spool and electrical system during transient conditions, then transient response is improved, but device complexity increases
Solution Approach 1:
The electric machine serves multiple functions: it acts as a motor to accelerate the high-pressure spool during transient conditions, as a generator to recover energy during deceleration, and as a controller to maintain optimal operating points. This multi-functionality reduces the need for separate systems for each function, thereby limiting the increase in overall device complexity while achieving improved transient response.
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 the engine's transient response, improves surge margin, and facilitates quicker transitions between operational conditions, reducing the challenges associated with high inertia during transient events.
Implementation Method 1
an electric machine and power unit, allowing for the transfer of power between the engine's high-pressure spool and external power sources or loads
Data Source
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AI summary
Aircraft engines and methods for operating such aircraft engines during transient conditions are described. An exemplary method comprises identifying a transient condition of the aircraft engine and at least partially absorbing the transient condition using an electrical system of the aircraft. When the transient condition requires acceleration of the engine, absorbing the transient condition may comprise transferring power from the electrical system to the high-pressure spool of the engine. When the transient condition requires deceleration of the engine, absorbing the transient condition may comprise transferring power from the high-pressure spool to the electrical system.