Spill Return Fuel Nozzle Layout to Limit 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 thermal stress and preventing coking.
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 fuel injector nozzle is segmented into multiple functional passages: an annular fuel passage for main fuel delivery, a central spill passage for excess fuel removal, and a swirl chamber. This segmentation allows different fuel streams to be managed separately, with the spill passage diverting excess fuel away from high-temperature zones to prevent coking and extend injector service life while maintaining high power output capability
Solution Approach 2:
The spill passage acts as an intermediary channel that mediates between the fuel supply system and the combustion chamber. It provides a separate pathway for excess fuel to bypass the high-temperature combustion zone, preventing thermal degradation and coking of the injector components while allowing the main fuel passage to operate at optimal high-pressure conditions for power generation
2Productivity
If higher combustion temperatures and pressures are used to improve efficiency, then energy conversion is improved, but fuel coking increases
Solution Approach 1:
The spill passage extracts excess fuel from the fuel delivery system before it can enter the high-temperature combustion chamber. By removing this excess fuel through a separate central passage, the system prevents the conditions that lead to coking while maintaining the high combustion temperatures and pressures needed for efficient energy conversion in the main fuel stream
Solution Approach 2:
The spill passage converts the potentially harmful effect of excess fuel (which would cause coking) into a beneficial feature by providing a dedicated escape route. The excess fuel that cannot be combusted is safely diverted through the spill passage, preventing thermal degradation and extending injector life while allowing the main combustion process to operate at optimal high-temperature conditions for efficiency
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 enhances the service life of the injectors by managing high temperatures and pressures, reducing coking, and improving the efficiency and reliability of combustion processes.
Implementation Method 1
The spill passage and discharge passage fluidly connect to opposite ends of the swirl chamber
Implementation Method 2
The plurality of fuel ports fluidly connects the annular fuel passage to the swirl chamber, each fuel port tangent to a peripheral wall of the swirl chamber
Data Source
AI summary
A nozzle for a fuel injector includes a fuel passage, a swirl chamber, a port, a discharge orifice, and a spill passage. The fuel passage fluidly connects to the port, which extends along a circumferential direction about the nozzle axis at a peripheral wall of the swirl chamber. The discharge orifice fluidly connects the end of the swirl passage to an outlet of the nozzle. The spill passage fluidly connects the end of the swirl chamber to a location upstream from the fuel passage.