Active Cooling for Fuel Injectors in Gas Turbines
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Solution Overview
Problem
Fuel injectors in gas turbine engines face challenges with high-temperature and high-pressure compressor air causing fuel coking, structural weakening, and corrosion, as standard heat shields become less effective in managing increasing temperatures and heat energy exposure.
Innovation Solution
An active cooling system is implemented in the fuel injector, which siphons cooled air from the compressor discharge area through a cooling passage, passing it through the injector, utilizing a heat exchanger to reduce heat transfer and maintain fuel temperature below coking levels, and incorporating a heat shield with a gap to enhance cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a standard heat shield with stagnant air is used, then heat transfer to the fuel injector is reduced, but the protection becomes insufficient at temperatures above 1600 degrees Fahrenheit and fuel temperatures above 350 degrees Fahrenheit
Solution Approach 1:
The patent transitions from a static stagnant air heat shield to a dynamic active cooling system where cooled air flows continuously through the fuel injector. The cooling air passage system actively circulates cooled air from the compressor discharge area through the fuel injector body, dynamically removing heat rather than relying on passive thermal barrier properties.
Solution Approach 2:
The patent introduces cooled air as an intermediary cooling medium that flows through the fuel injector. This cooled air acts as a heat transfer intermediary, absorbing excess heat from the fuel injector components and carrying it away, thereby protecting the fuel and injector structures from direct high-temperature exposure.
2Use of energy by moving object
If fuel is used as a heat sink for cooling other systems, then cooling capacity for other components is improved, but fuel temperature rises sharply to 350 degrees Fahrenheit or higher causing coking and injector damage
Solution Approach 1:
The patent implements a self-service cooling mechanism where the fuel injector uses its own cooling air passage system to cool itself. The cooled air flows through passages within the fuel injector body, providing self-cooling that prevents the fuel and injector components from overheating, even when the fuel is being used as a heat sink elsewhere in the system.
Solution Approach 2:
The patent applies preliminary cooling by pre-cooling the air before it enters the fuel injector. The cooling air is cooled in advance in the compressor discharge area and then directed through the fuel injector, providing proactive thermal management before the fuel and injector components can overheat.
3Power
If the fuel injector is exposed to higher environment temperatures to meet increasing engine performance requirements, then engine performance is improved, but fuel coking and structural weakening occur
Solution Approach 1:
The patent applies local quality by providing targeted cooling specifically at the fuel injector location where high temperatures cause the most damage. The cooling air passages are strategically positioned within the fuel injector body to deliver cooling exactly where needed, protecting critical components while allowing the overall engine environment to operate at high temperatures for improved performance.
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 active cooling system effectively reduces heat transfer to the fuel injector, preventing coking and maintaining structural integrity, while the heat exchanger cools the air and fuel, enhancing fuel injector performance and extending the lifespan of metal components.
Implementation Method 1
a cooling passage that has an inlet within a compressor discharge area and an outlet in a combustor as well as portion in thermal communication with the fuel injector
Implementation Method 2
An active cooling system is implemented in the fuel injector, which siphons cooled air from the compressor discharge area through a cooling passage
Implementation Method 3
utilizing a heat exchanger to reduce heat transfer and maintain fuel temperature below coking levels
Implementation Method 4
incorporating a heat shield with a gap to enhance cooling efficiency
Data Source
AI summary
A fuel injector and turbine engine incorporating the fuel injector are provided. The fuel injector includes an active cooling system that insulates fuel flowing through the fuel injector from heat energy within the turbine engine. The cooling system includes a cooling air passage that includes an inlet and an outlet. The inlet and outlet are in fluid communication with the interior of an engine case of the turbine engine. The inlet is at a higher air pressure location than the outlet such that air is siphoned through the cooling air passage. A portion of the cooling air passage includes a heat exchanger for extracting heat energy from the cooling air. The cooling air passes through the fuel injector after it has passed through the heat exchanger. The heat exchanger is positioned external to the engine case and in thermal communication with the ambient.