Dual-Spool Power Transfer Control for Gas Turbine Spool Stability
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Solution Overview
Problem
Increasing engine bypass ratios and electrical demands on the compressor section of gas turbine engines lead to increased operating temperatures and power fluctuations, affecting engine performance.
Innovation Solution
A dual-spool power management system with motor-generators and a controller that dynamically manages power transfer between low and high speed spools, combining or directing power between them to optimize efficiency and thrust, reduce idle exhaust temperatures, and stabilize spool speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If engine bypass ratios and electrical demands on the compressor section are increased, then power output and electrical generation capacity are improved, but operating temperatures increase and power fluctuations worsen
Solution Approach 1:
The engine is divided into two independent spool systems (low-speed spool with first turbine, high-speed spool with second turbine) that can operate semi-independently. Each spool has its own motor-generator unit, allowing separate control of power extraction and temperature management for each spool, thereby managing overall operating temperatures while maintaining high power output
Solution Approach 2:
The controller dynamically adjusts operational parameters including motor-generator loading, spool speeds, and power distribution between the two spools. By changing these parameters in response to operating conditions, the system optimizes the balance between power output and temperature control
2Power
If engine bypass ratios and electrical demands on the compressor section are increased, then power output is improved, but power fluctuations and operating perturbation increase
Solution Approach 1:
The controller continuously monitors operating conditions including spool speeds, power demand, and temperature, then adjusts motor-generator loading and power distribution in real-time. This feedback control stabilizes power output by compensating for fluctuations and maintaining optimal operating points across varying demand conditions
Solution Approach 2:
The system employs dynamic control where the controller adapts operating parameters such as spool speeds and motor-generator extraction rates in real-time. This dynamic adjustment allows the system to respond to changing power demands while maintaining stability and reducing oscillations in power output
3Adaptability or versatility
If motor-generators are used for power extraction and management, then power distribution control is improved, but device complexity increases
Solution Approach 1:
Each motor-generator unit serves multiple functions: it acts as a power extraction device during normal operation, a starter motor for cold engine starting, and a means for spool speed control. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in overall system complexity while maintaining versatile power distribution control
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
Enhances engine efficiency by stabilizing spool speeds, reducing compressor stall margins, and improving thrust by dynamically managing power distribution during varying operational conditions.
Implementation Method 1
A low spool motor-generator and a high spool motor-generator may be configured to receive and input power to respective low and high speed spools of a gas turbine engine
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.