Three-Circuit Fuel Nozzle Staging for Intermediate-Flow Stability
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Solution Overview
Problem
Dual circuit fuel injectors in gas turbine engines face inefficiencies at intermediate flow conditions, where secondary fuel velocity is too low to reach certain combustor zones, leading to suboptimal combustion efficiencies and instabilities.
Innovation Solution
A fuel nozzle design with three fluidly isolated fuel circuits, each issuing fuel flows through distinct outlet orifices, allowing for precise control and staging of fuel flows to optimize combustion, including a first circuit for ignition, a second circuit for high-pressure penetration, and a third circuit for swirling fuel to enhance coverage and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a dual circuit fuel injector is used, then fuel flow capacity is increased for the secondary circuit, but the secondary fuel velocity becomes too low to reach certain combustor zones at intermediate flow conditions
Solution Approach 1:
The fuel delivery system is segmented into three separate circuits (first, second, and third fuel circuits) with distinct outlet orifices positioned at different locations. This segmentation allows each circuit to be optimized for specific functions: the first circuit for ignition with precise control, the second circuit for high-velocity penetration to distant zones, and the third circuit for supplemental flow. By dividing the single dual-circuit system into three independent circuits, the patent resolves the contradiction by enabling the second circuit to maintain high velocity while providing adequate flow capacity through its dedicated pathway.
Solution Approach 2:
Different outlet orifices are positioned at specific locations within the nozzle body to create localized fuel delivery zones. The first outlet orifice is positioned for ignition zone delivery, the second outlet orifice is positioned to deliver high-velocity fuel to distant combustor zones, and the third outlet orifice provides supplemental flow. This local quality approach allows each circuit to target specific spatial regions with optimized flow characteristics, resolving the contradiction between flow capacity and velocity by matching the right circuit to the right location.
2Quantity of substance
If the secondary circuit is activated at intermediate flow rates, then fuel flow capacity is increased, but combustion efficiency decreases due to insufficient fuel velocity
Solution Approach 1:
The fuel delivery system is segmented into three separate circuits (first, second, and third fuel circuits) with distinct outlet orifices positioned at different locations. This segmentation allows each circuit to be optimized for specific functions: the first circuit for ignition with precise control, the second circuit for high-velocity penetration to distant zones, and the third circuit for supplemental flow. By dividing the single dual-circuit system into three independent circuits, the patent resolves the contradiction by enabling the second circuit to maintain high velocity while providing adequate flow capacity through its dedicated pathway.
Solution Approach 2:
The patent changes the flow parameters by creating three separate circuits with different flow characteristics. The second fuel circuit is specifically designed to maintain high velocity even at intermediate flow rates by having its own dedicated outlet orifice positioned for optimal penetration. This parameter change allows the system to achieve both adequate flow capacity and sufficient velocity simultaneously, thereby maintaining combustion efficiency while increasing overall fuel flow capacity.
3Device complexity
If a single dual circuit fuel injector is used, then device complexity is reduced, but the ability to control and stage fuel flows precisely is limited
Solution Approach 1:
The fuel delivery system is segmented into three separate circuits (first, second, and third fuel circuits) with distinct outlet orifices positioned at different locations. This segmentation allows each circuit to be optimized for specific functions: the first circuit for ignition with precise control, the second circuit for high-velocity penetration to distant zones, and the third circuit for supplemental flow. By dividing the single dual-circuit system into three independent circuits, the patent resolves the contradiction by enabling the second circuit to maintain high velocity while providing adequate flow capacity through its dedicated pathway.
Solution Approach 2:
The patent introduces dynamic control capabilities through the three independent fuel circuits, each capable of being activated or deactivated independently based on combustion requirements. This dynamic architecture allows precise staging of fuel flows - the first circuit can be activated for ignition, then the second circuit can be activated for high-velocity delivery, with the third circuit providing supplemental flow as needed. This dynamic flexibility provides precise control over fuel delivery timing and amount, resolving the contradiction between structural simplicity and operational precision.
Data Source
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AI summary
In accordance with at least one aspect of this disclosure, a nozzle for a fuel injector includes, a nozzle body (110) defining a central axis from a nozzle inlet (112) to a nozzle outlet (114). A first fuel circuit (122) is defined in the nozzle body (110) configured to issue a first fuel flow from a first outlet orifice (126) into a combustor. A second fuel circuit (128) is defined in the nozzle body (110) radially outward from the first fuel circuit (122) configured to issue a second fuel flow from a second outlet orifice (132) at a prefilmer surface of the nozzle body (110). A third fuel circuit (136) is defined in the nozzle body (110) radially outward from the second fuel circuit (128) configured to issue a third fuel flow from a third outlet orifice (140) at the prefilmer surface of the nozzle body (110). In embodiments, the first fuel circuit (122), the second fuel circuit (128), and the third fuel circuit (136) can all be fluidly isolated from one another within the nozzle body (110).