Hybrid Electric Compressor Stability Control via Spool Power Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas turbine engines face challenges in maintaining compressor stability while minimizing the use of engine bleeds, which can impact performance and efficiency, and active control of variable stator vanes can lead to increased inter-turbine temperatures and reduced engine lifespan.
Innovation Solution
A hybrid electric propulsion system that transfers power between the electric generator of the low speed spool and the electric motor of the high speed spool, using a controller to manage power transfers and adjust vane angles to maintain compressor stability without changing the output of the low pressure compressor vane actuator, thereby reducing exhaust gas temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If engine bleeds are used to extract engine bleed air to maintain compressor stability, then compressor stability is improved, but engine performance and efficiency deteriorate
Solution Approach 1:
The patent extracts the function of maintaining compressor stability from the traditional engine bleed system and transfers it to a dedicated compressor stability control system using variable stator vanes. This separates the stability control function from the main engine flow path, allowing stability maintenance without extracting bleed air that would reduce engine performance.
Solution Approach 2:
The patent introduces variable stator vanes as an intermediary mechanism between the compressor inlet and the compressor stages. These vanes actively control airflow angles and distribution, providing stability enhancement without directly removing air from the engine core flow path, thus avoiding the performance penalty associated with engine bleeds.
2Stability of the object's composition
If active control of variable stator vanes is used to improve air flow and prevent stalling, then compressor stability is improved, but inter-turbine temperatures increase and engine lifespan is reduced
Solution Approach 1:
The patent employs dynamically adjustable variable stator vanes that can change their angle of attack in real-time based on operating conditions. This dynamic control optimizes airflow through the compressor stages across different power settings, maintaining stability margins without creating excessive temperature rises that would occur with fixed or less adaptive vane configurations.
Solution Approach 2:
The patent changes the geometric parameters of the airflow path by adjusting vane angles to optimize compressor performance. By modifying the flow direction and distribution parameters through variable stator vanes, the system achieves improved stability and reduced temperature rise compared to conventional fixed-geometry compressors or those using engine bleeds.
3Stability of the object's composition
If variable stator vanes are controlled to maintain compressor stability, then air flow and stalling prevention are improved, but exhaust gas temperatures increase
Solution Approach 1:
The patent utilizes variable stator vane angle adjustments to optimize the compressor's pressure ratio and airflow characteristics. By changing the geometric parameters of the compressor inlet and intermediate stages, the system improves stability and reduces downstream temperatures, including exhaust gas temperatures, compared to conventional control methods.
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 approach enhances compressor stability and reduces inter-turbine temperatures, improving engine efficiency and lifespan by dynamically managing power between spools and adjusting vane angles, while maintaining constant thrust.
Implementation Method 1
transfers power between the electric generator of the low speed spool and the electric motor of the high speed spool
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A hybrid electric propulsion system (100) includes a gas turbine engine (120) having a low speed spool (30) and a high speed spool (32). The low speed spool includes a low pressure compressor (44) and turbine (46), and the high speed spool includes a high pressure compressor (52) and turbine (54). The hybrid electric propulsion system includes an electric generator (213A) configured to extract power from the low speed spool (30), an electric motor (212B) configured to augment rotational power of the high speed spool (32), and a controller (256). The controller is operable to determine (602) a target operating condition of the low pressure compressor (44) to achieve a compressor stability margin in the gas turbine engine, determine (604) a current operating condition of the low pressure compressor (44), and control (606) a power transfer between the electric generator (213A) of the low speed spool (30) and the electric motor (212B) of the high speed spool (32) to adjust the current operating condition based on the target operating condition.