Helical Fuel Nozzle Cooling for Gas Turbine O-Ring Cost Reduction
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Solution Overview
Problem
High-temperature fuel nozzles in gas turbine engines require expensive high-thermal-resistance O-rings due to heat buildup, especially during reduced fuel flow conditions, necessitating a cost-effective cooling solution.
Innovation Solution
A fuel nozzle design featuring a flange and stem with an internal fuel circuit and a helical coolant path between the flange and stem, where fuel circulates as a coolant to maintain lower temperatures and allow the use of less expensive O-rings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-thermal-resistance O-rings are used to withstand high temperatures in fuel nozzles, then the reliability and temperature resistance are improved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent applies preliminary cooling action by introducing a coolant flow through the flange before fuel reaches the nozzle. The flange contains cooling channels that pre-cool the fuel and dissipate heat generated in the combustor, preventing excessive temperature buildup that would require expensive high-thermal-resistance O-rings. This preliminary thermal management allows the use of standard, lower-cost sealing materials.
2Loss of energy
If fuel flow is reduced during descent operations, then fuel consumption is optimized, but the cooling effect on fuel nozzles is reduced causing temperature increase
Solution Approach 1:
The patent segments the cooling function from the fuel injection function by providing dedicated cooling channels in the flange structure. This allows independent control of cooling flow through the flange while maintaining reduced fuel flow to the combustor during descent. The segmented design ensures continuous cooling protection even when overall fuel consumption is minimized.
3Reliability
If multiple O-rings are provided at each fuel nozzle inlet to ensure sealing, then the sealing reliability is improved, but the number of components and assembly complexity increase
Solution Approach 1:
The patent uses a standardized O-ring sealing design that has been proven effective in lower-temperature applications. By controlling temperature through cooling channels, the system can replicate successful sealing designs from other engine components rather than requiring custom high-temperature sealing solutions. This copying of proven designs reduces component variety and simplifies assembly procedures.
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 effectively reduces the internal temperature of the fuel nozzles, enabling the use of economical O-rings by maintaining cooling even during reduced fuel flow, thereby reducing material costs and ensuring reliable operation.
Implementation Method 1
circulating the fuel in a helical path between the outlet port of the flange and an outer surface of the stem, the fuel being used as a coolant
Implementation Method 2
the fuel circulating as a coolant to maintain lower temperatures
Data Source
AI summary
In the fuel nozzle, the fuel is circulated in a helical path around the interface of a stem of the fuel nozzle and a flange for increase the cooling.