Dual-Spool Power Extraction for Compressor Stability and Temperature Control
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Solution Overview
Problem
Increasing engine bypass ratios and electrical demands on gas turbine engines lead to increased loading on the compressor section, resulting in detrimental operating temperatures and power fluctuations.
Innovation Solution
A dual-spool power extraction system with motor-generators and a controller that dynamically manages power distribution between low and high spools based on operational data, including fan inlet temperature, combustor outlet temperature, and throttle position, to optimize spool speeds and reduce compressor stall margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If engine bypass ratio is increased to meet electrical demands, then power output is improved, but operating temperature increases and compressor stability deteriorates
Solution Approach 1:
The engine is divided into two independent spool systems (high-pressure spool and low-pressure spool) that can be controlled separately. This allows the high-pressure spool to maintain optimal compressor operation while the low-pressure spool handles power generation, resolving the contradiction between power output and operating temperature.
Solution Approach 2:
The system dynamically switches between different operational modes (dual-spool mode, single-spool mode, push-power mode) based on real-time conditions such as temperature, power demand, and compressor stability. This dynamic adaptation allows the engine to optimize power output while maintaining safe operating temperatures.
2Power
If engine bypass ratio is increased to meet electrical demands, then power output is improved, but compressor stability deteriorates
Solution Approach 1:
The compression system is segmented into high-pressure and low-pressure compressors on separate spools. This segmentation allows independent control of compression ratios, enabling the high-pressure compressor to maintain stable operation while the overall system delivers high power output.
Solution Approach 2:
The system changes operational parameters (spool speeds, power distribution, operational mode) based on real-time compressor stability conditions. When compressor stability is compromised, the system adjusts parameters to restore stability while maintaining power output through the dual-spool architecture.
3Productivity
If power is pushed between spools during off-peak demand, then engine efficiency is improved, but system complexity increases
Solution Approach 1:
The motor-generators on each spool serve multiple functions: they can generate power during peak demand, consume power during push-power operations, and operate independently or in coordination. This multi-functionality enables efficiency improvements through power sharing while using standardized components that limit complexity growth.
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
The system enhances engine efficiency by combining power outputs during peak demand and directing power between spools during off-peak demand, reducing idle thrust and exhaust temperatures, and increasing thrust and efficiency.
Implementation Method 1
a low spool motor-generator mechanically connected to the low spool transmission, and a high spool motor-generator mechanically connected to the high spool transmission
Data Source
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AI summary
A power extraction system (100) for a gas turbine engine (20) may comprise a low spool transmission (72) and a low spool accessory gearbox (70). The low spool accessory gearbox may comprise a generator (76) and a dual clutch transmission. The dual clutch transmission may be coupled between the low spool transmission and the generator.