Effusion-Cooled Fuel Nozzle Tip for Thermal Stress and Coking
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Solution Overview
Problem
Fuel injectors in combustion systems face high heat flux and thermal stress, particularly in unprotected nozzle regions, leading to increased coking risk.
Innovation Solution
Incorporation of effusion passages in the fuel injector cap to divert oxidant flow across exposed surfaces, providing thermal protection by distributing oxidant flow to cool these regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If heat shields are used to thermally protect fuel injectors, then thermal protection is improved, but portions of the fuel injector nozzle remain unprotected
Solution Approach 1:
The cap is provided with effusion passages that allow cooling oxidant to effuse through the cap structure, creating a porous-like cooling effect across the entire nozzle surface including areas not directly covered by traditional heat shields. This porous approach enables thermal protection of previously unprotected regions.
Solution Approach 2:
The cap structure integrates multiple functions: it serves as a structural component, a cooling distribution system through effusion passages, and a protective element for the nozzle. This multi-functionality allows comprehensive thermal protection without adding separate dedicated cooling components.
2Object-affected harmful factors
If effusion passages are added to cool unprotected regions, then thermal protection is improved, but device complexity increases
Solution Approach 1:
The effusion passages are integrated directly into the cap structure, merging the cooling function with the existing cap component. This consolidation avoids adding a separate cooling device and reduces overall system complexity while achieving enhanced thermal protection.
Solution Approach 2:
The cap material and structure are designed with specific parameters (effusion passage dimensions, distribution pattern) that enable effective cooling. By optimizing these parameters, the system achieves thermal protection without requiring complex active control systems or multiple components.
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
Effusion passages effectively reduce thermal stress and coking risk in fuel injector nozzles by maintaining efficient oxidant-fuel mixing and atomization while protecting against high temperatures.
Implementation Method 1
effusion passages divert oxidant flow across exposed surfaces of injector 10 and thereby provide thermal protection
Implementation Method 2
effusion passages divert oxidant flow across exposed surfaces of injector 10 and thereby provide thermal protection
Data Source
Figure 1
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Figure 4~5
AI summary
A fuel injector (10) includes a nozzle (18) and a cap (26) for delivering an oxidant-fuel mixture along a nozzle axis (A). The nozzle (18) includes a fuel passage and a swirler (24). The fuel passage extends along the nozzle axis (A). The swirler (24) circumscribes the fuel passage and includes an oxidant passage (30A) that converges towards the nozzle axis (A). The cap (26) includes a peripheral body (34), an end body (36), and an effusion passage (28A). The peripheral body (34) circumscribes the swirler (24). The end body (36) joins to the peripheral body (34) and extends radially towards the nozzle axis (A). The effusion passage (28A) extends through the cap (26) to intersect at least one of the peripheral body (34) and the end body (36).