Spill Return Fuel Nozzle Layout to Reduce Injector Coking
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Solution Overview
Problem
Combustor and turbine performance in gas turbine engines are affected by the balance between higher pressure ratios and core gas path temperatures, leading to decreased injector service life and fuel coking due to high combustion temperatures and pressures.
Innovation Solution
A fuel injector design featuring an annular fuel passage, swirl chamber, multiple fuel ports, discharge passage, and spill passage, which includes a spill passage connecting to the fuel path upstream of the annular passage, allowing excess fuel to be diverted away from the combustion chamber, thereby reducing stress and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If higher pressure ratios and core gas path temperatures are used to improve combustor and turbine performance, then power output and efficiency are improved, but injector service life decreases and fuel coking occurs
Solution Approach 1:
The spill passage extracts excess fuel from the fuel injection system before it can enter the combustion chamber and undergo coking. By removing the harmful excess fuel through a dedicated spill passage that connects to the fuel return line, the system protects the injector from degradation while maintaining the high pressure ratios and temperatures needed for power output.
Solution Approach 2:
The spill passage acts as an intermediary component between the fuel injection system and the combustion chamber. It provides a controlled path for excess fuel to bypass the combustion chamber, preventing direct contact between the high-temperature combustion environment and the fuel that would otherwise cause coking and injector degradation.
2Power
If higher pressure ratios and core gas path temperatures are used to improve combustor and turbine performance, then power output and efficiency are improved, but fuel coking occurs
Solution Approach 1:
The spill passage extracts excess fuel from the fuel injection system before it can enter the combustion chamber and undergo coking. By removing the harmful excess fuel through a dedicated spill passage that connects to the fuel return line, the system protects the injector from degradation while maintaining the high pressure ratios and temperatures needed for power output.
Solution Approach 2:
Instead of allowing excess fuel to cause harmful coking in the combustion chamber, the spill passage redirects this excess fuel through a controlled path back to the fuel supply system. The potentially harmful excess fuel is converted into a manageable flow that can be replenished in the fuel supply, transforming a problem into a controllable aspect of the fuel management system.
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 design extends injector life and reduces coking by managing high temperatures and pressures, improving the efficiency and reliability of the combustion process.
Implementation Method 1
The spill passage fluidly connects the swirl chamber to the fuel path upstream of the annular fuel passage
Implementation Method 2
The plurality of fuel ports fluidly connects the annular fuel passage to the swirl chamber
Data Source
Figure 1
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AI summary
A nozzle (20) for a fuel injector (10) includes a fuel passage (40), a swirl chamber (42), a port (44), a discharge orifice, and a spill passage (48). The fuel passage (40) fluidly connects to the port (44), which extends along a circumferential direction about the nozzle axis (A) at a peripheral wall of the swirl chamber (42). The discharge orifice fluidly connects the end of the swirl passage to an outlet (50) of the nozzle (20). The spill passage (48) fluidly connects the end of the swirl chamber (42) to a location upstream from the fuel passage (40).