Engine Power Extraction Control Circuit for Aircraft
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Solution Overview
Problem
Aircraft main propulsion engines face increased shaft power extraction demands in more electric architectures, leading to reduced compressor surge margin, higher fuel burn rates, and increased residual thrust during high power extraction, particularly during flight and ground idle conditions.
Innovation Solution
A system and method that includes a gas turbine engine with high and low pressure turbines, coupled to generators and control units, which convert rotational energy into electrical energy, with an engine power extraction control circuit that adjusts energy extraction based on aircraft thrust and electrical load requirements to maintain surge margin and reduce residual thrust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If shaft power extraction demand is increased to supply electrical power in more electric aircraft architectures, then electrical power generation is improved, but compressor surge margin deteriorates
Solution Approach 1:
The system dynamically adjusts engine operating parameters including shaft power extraction levels and compressor bleed settings based on real-time aircraft electrical power demands and flight conditions. This dynamic control allows the engine to adapt to varying power extraction requirements while maintaining compressor surge margin through active parameter modification.
Solution Approach 2:
The control system modifies key engine parameters such as shaft power extraction amount, compressor bleed settings, and engine speed to optimize the balance between electrical power generation and compressor surge margin. By changing these parameters adaptively, the system resolves the contradiction between meeting high electrical power demands and maintaining safe compressor operation.
2Reliability
If engine speed is increased to mitigate compressor surge margin deterioration during high shaft power extraction, then compressor surge margin is improved, but fuel burn rate increases
Solution Approach 1:
Instead of uniformly increasing engine speed across all operating conditions, the system applies partial action by selectively adjusting engine speed and shaft power extraction only when and where needed to maintain compressor surge margin. This avoids unnecessary fuel burn increases during conditions where full speed enhancement is not required.
Solution Approach 2:
The system employs dynamic control to adjust engine speed and shaft power extraction in real-time based on actual compressor surge margin requirements and flight conditions, rather than using fixed high-speed operation. This dynamic adaptation minimizes fuel burn rate while maintaining adequate surge margin during high electrical power extraction.
3Reliability
If engine speed is increased during high shaft power extraction, then compressor surge margin is improved, but residual thrust increases
Solution Approach 1:
The control system modifies engine operating parameters including shaft power extraction levels and compressor bleed settings to maintain compressor surge margin without necessarily increasing engine speed. By changing these parameters strategically, the system avoids the residual thrust increase that would result from blanket engine speed enhancement.
Solution Approach 2:
The system dynamically adjusts shaft power extraction and compressor bleed settings in real-time to maintain adequate surge margin during high electrical power extraction, thereby avoiding the need to increase engine speed and the associated residual thrust increase.
4Power
If shaft power extraction demand is increased to meet electrical load requirements, then electrical power supply is improved, but fuel burn rate increases
Solution Approach 1:
The control system dynamically optimizes shaft power extraction levels and engine operating parameters based on actual aircraft electrical load requirements and flight conditions. This dynamic control enables the system to meet electrical power supply demands while minimizing fuel burn rate by avoiding excessive shaft power extraction and unnecessary engine speed increases.
Solution Approach 2:
The system strategically modifies engine operating parameters including shaft power extraction amount and compressor bleed settings to achieve the required electrical power supply efficiency. By optimizing these parameter changes, the system resolves the contradiction between meeting electrical load requirements and minimizing fuel burn rate.
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
Improves compressor surge margin and overall engine operability during high power extraction demands, reducing fuel burn rates and minimizing residual thrust generation.
Implementation Method 1
The first generator is coupled to receive at least a portion of the rotational energy generated by the high pressure turbine and is operable, upon receipt thereof, to generate electrical energy. The second generator is coupled to receive at least a portion of the rotational energy generated by the low pressure turbine and is operable, upon receipt thereof, to generate electrical energy.
Data Source
AI summary
An engine power extraction control system controls the main propulsion engines and the electrical machines that are coupled thereto to supply an appropriate amount of aircraft thrust and electrical energy to the aircraft. The engines and electrical machines are also controlled so that the propulsion thrust that is generated is split between the various turbines in the main propulsion engines to maintain an adequate surge margin and to minimize residual thrust generation.