Staged Combustion Fuel Switching for Low-Emission Gas Turbines
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Solution Overview
Problem
The aviation industry is seeking alternatives to traditional kerosene-based jet fuels, and existing gas turbine engines face challenges in efficiently managing emissions and combustion efficiency when using fuels with different characteristics.
Innovation Solution
A staged combustion system in a gas turbine engine that utilizes pilot and main fuel injectors, with a fuel delivery regulator controlling fuel from two sources with different characteristics, allowing flexible fuel supply to the injectors based on operation ranges and conditions to minimize emissions like nvPM and optimize combustion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single fuel source with uniform characteristics is used for all operation ranges, then the fuel supply system is simple, but combustion efficiency and emissions control cannot be optimized across different operating conditions
Solution Approach 1:
The fuel supply system is segmented into multiple fuel sources (e.g., conventional jet fuel and alternative fuel) with different characteristics, allowing each fuel type to be supplied to the combustor during specific operation ranges. This segmentation enables optimization of combustion efficiency and emissions control for each operating condition while maintaining manageable system complexity through dedicated delivery pathways for each fuel type.
Solution Approach 2:
The fuel delivery system incorporates dynamic control mechanisms that adjust fuel source selection and delivery parameters in real-time based on operating conditions. The system can dynamically switch between different fuel sources and adjust fuel flow rates to optimize combustion performance across varying operating ranges, thereby achieving adaptability without requiring complete system redesign.
2Object-affected harmful factors
If fuel characteristics are changed to reduce nvPM emissions, then emissions control improves, but combustion efficiency may deteriorate under certain operating conditions
Solution Approach 1:
Different fuel characteristics are applied locally to different operation ranges of the combustor. Alternative fuels with lower nvPM emissions are supplied during specific operating conditions (e.g., cruise mode) where emissions reduction is prioritized, while conventional fuels with superior combustion characteristics are used during other conditions (e.g., acceleration mode) where combustion efficiency is critical. This localized quality approach allows simultaneous optimization of both emissions and efficiency.
Solution Approach 2:
The system changes fuel parameters (type, composition, calorific value) dynamically based on operating conditions to achieve optimal performance. By adjusting fuel characteristics as a variable parameter rather than using a fixed fuel type, the system can reduce nvPM emissions during certain operating ranges while maintaining combustion efficiency during others, effectively resolving the contradiction between emissions control and productivity.
3Productivity
If multiple fuel sources with different characteristics are supplied to the combustor, then combustion optimization is achieved, but the fuel delivery control system becomes more complex
Solution Approach 1:
The fuel delivery regulator is designed with multi-functionality to handle multiple fuel sources with different characteristics through a unified control architecture. The regulator incorporates universal interfaces and control logic that can manage various fuel types, allowing the system to achieve combustion optimization with multiple fuels while preventing excessive complexity through shared control mechanisms and standardized delivery pathways.
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 reduces emissions and improves combustion efficiency by selectively using fuels with different characteristics, particularly during cruise and acceleration modes, minimizing nvPM production and maintaining optimal engine performance.
Implementation Method 1
a fuel delivery regulator arranged to control delivery of fuel to the pilot and main fuel injectors
Implementation Method 2
a staged combustion system having pilot fuel injectors and main fuel injectors
Data Source
AI summary
A aircraft gas turbine engine and operation method, the engine including: a staged combustion system having pilot and main fuel injectors, and operates in a pilot-only range wherein fuel delivers to pilot fuel injectors, and a pilot-and-main operation range wherein fuel is delivered to at least the main fuel injectors. The engine further includes a fuel delivery regulator to pilot and main fuel injectors, which receives fuel from a first and second source containing fuels each with different characteristics. The staged combustion system switches between pilot-only and pilot-and-main range operation when in steady cruise mode, the mode defining a boundary between first and second engine cruise operation range. The fuel delivery regulator delivers fuel to pilot fuel injectors during at least part of the first engine cruise operation with different fuel characteristics from fuel delivered to one or both pilot and main fuel injectors the second engine cruise operation range.