Distributed Propulsion Generator Power Ratio Control
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Solution Overview
Problem
Current systems face challenges in efficiently generating high electric power while providing propulsive thrust and component cooling in a compact, lightweight configuration, especially in distributed propulsion architectures, where the use of separate gas turbine engines for power generation adds significant weight, cost, and complexity.
Innovation Solution
A dual-spool turbofan gas turbine engine configuration where a low-pressure turbine is coupled to a fan and an electrical generator, generating both mechanical power for propulsive thrust and electrical power, with a controller managing the power distribution to auxiliary fans and electrical loads to optimize power ratios and reduce engine diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a separate gas turbine engine (IPU/APU) is used for electric power generation, then electric power demand is met, but weight, cost, and system complexity increase significantly
Solution Approach 1:
The patent combines the electric power generation function with the existing propulsion gas turbine engine by directly connecting an electrical generator to the low-pressure spool. This integration eliminates the need for a separate IPU/APU, thereby reducing system complexity, weight, and cost while still meeting high electric power demands (up to 1 megawatt).
Solution Approach 2:
The gas turbine engine is designed to serve dual purposes: providing propulsive thrust through the fan and simultaneously generating electrical power through the electrical generator connected to the low-pressure spool. This multi-functionality allows a single engine to replace both the propulsion engine and the separate power generation unit.
2Power
If power extraction from high-pressure or low-pressure spool is increased to drive generator, then electric power generation increases, but stable operating range of compressor is detrimentally impacted
Solution Approach 1:
The system dynamically adjusts the power extraction from the low-pressure spool based on operating conditions. The electrical generator is directly connected to the low-pressure spool, allowing flexible control of power extraction that adapts to varying flight conditions while maintaining compressor stability. This dynamic control prevents detrimental impacts on the compressor's stable operating range.
Solution Approach 2:
The patent changes the operating parameters by extracting power specifically from the low-pressure spool rather than the high-pressure spool, and by controlling the extraction level to maintain compressor stability. This parameter change allows high electric power generation while preserving the compressor's stable operating characteristics.
3Temperature
If 3rd stream bypass air is used for cooling electrical components, then cooling effectiveness improves, but engine diameter increases
Solution Approach 1:
The patent extracts cooling air from the traditional two-stream bypass configuration and redirects it specifically for cooling electrical components. By taking out the cooling function and integrating it with the existing bypass air flows, the system achieves effective cooling without requiring an additional 3rd stream that would increase engine diameter.
Solution Approach 2:
The bypass air streams are designed to serve multiple functions: providing thrust through mass flow and simultaneously cooling electrical components. This multi-functionality allows the existing bypass air to be used for cooling purposes without requiring additional engine diameter or separate cooling systems.
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
Enables efficient high electric power extraction, propulsive thrust, and component cooling in a more compact and lighter weight configuration, improving aircraft performance and reducing the need for separate power units.
Implementation Method 1
at least a low-pressure turbine coupled to a fan via a low-pressure spool, and the low-pressure turbine is configured to generate mechanical power
Implementation Method 2
The electrical generator is directly connected to the low-pressure spool and is disposed downstream of the low-pressure turbine. The electrical generator is configured, upon receiving a portion of the mechanical power generated by the low-pressure turbine, to generate a total amount of electrical power (Pe)
Implementation Method 3
A concept that has recently been developed is a turbofan engine configured with two separate, concentric bypass streams, with the outermost stream being designated as the '3rd stream.' This air, like the traditional turbofan bypass air, bypasses the core of the engine. The 3rd stream air is sufficiently pressurized, but is also low enough in temperature, to provide effective cooling for the electrical components.
Data Source
AI summary
A propulsion and electric power generation system includes a gas turbine propulsion engine, an electrical generator, an aircraft power distribution system, a plurality of auxiliary fans, and a controller. The gas turbine propulsion engine includes at least a low-pressure turbine coupled to a fan via a low-pressure spool, and the low-pressure turbine is configured to generate mechanical power. The electrical generator is directly connected to the low-pressure spool and generates a total amount of electrical power (Pe). The aircraft power distribution system receives a first fraction (Pa) of the total amount of electrical power. The auxiliary fans receive a second fraction (Pf) of the total amount of electrical power. The controller is configured to control a ratio of Pf to Pa (Pf/Pa) such that the ratio spans a range from less than 0.6 to at least 0.9.