Fuel Nozzle Tip Effusion Cooling for Thermal Protection and Coking
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Solution Overview
Problem
Existing fuel injector designs fail to protect fuel injectors from high-temperature exposure, and existing heat shields do not adequately protect fuel injector nozzle portions from high-temperature exposure, and coking remains unprotected.
Innovation Solution
A fuel injector nozzle and cap design that includes a swirler and effusion passages to divert oxidant flow across exposed surfaces, providing thermal protection by mixing oxidant with fuel to create a cooling effect.
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 includes effusion passages that allow oxidant to flow through the cap material in a porous manner, creating a cooling film across surfaces that traditional solid heat shields cannot protect. This porous flow approach enables thermal protection of previously unprotected nozzle portions.
Solution Approach 2:
The invention uses pneumatic principles by directing oxidant flow through effusion passages in the cap, utilizing gas flow dynamics to create a protective cooling atmosphere around hot surfaces, rather than relying solely on solid thermal barrier materials.
2Object-affected harmful factors
If traditional heat shields are used, then some thermal protection is achieved, but coking risk in internal fuel passages increases
Solution Approach 1:
The effusion passages act as an intermediary mechanism that introduces cooling oxidant flow between the hot combustion environment and the fuel injector components, particularly protecting internal fuel passages from temperatures that cause coking.
Solution Approach 2:
By directing oxidant flow through effusion passages, the invention creates a cooler, more controlled atmospheric environment around fuel passages, reducing thermal exposure that leads to carbon deposition and coking.
3Stress or pressure
If oxidant flow is diverted through effusion passages, then thermal stress is reduced, but device complexity increases
Solution Approach 1:
The cap serves multiple functions: it contains effusion passages for cooling, provides structural support, and directs oxidant flow. This multi-functionality reduces the need for separate cooling components, managing complexity while achieving thermal stress reduction.
Solution Approach 2:
The cooling function is merged into the cap structure itself through integrated effusion passages, rather than being a separate system. This combination achieves thermal protection while minimizing additional complexity.
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 thermal stress and coking potential on fuel injector components by diverting oxidant flow to cool exposed surfaces, maintaining optimal operating conditions.
Implementation Method 1
Effusion passages divert oxidant flow across exposed surfaces of injector 10 and thereby provide thermal protection
Implementation Method 2
diverting oxidant flow to cool exposed surfaces, maintaining optimal operating conditions
Data Source
AI summary
A fuel injector includes a nozzle and a cap for delivering an oxidant-fuel mixture along a nozzle axis. The nozzle includes a fuel passage and a swirler. The fuel passage extends along the nozzle axis. The swirler circumscribes the fuel passage and includes an oxidant passage that converges towards the nozzle axis. The cap includes a peripheral body, an end body, and an effusion passage. The peripheral body circumscribes the swirler. The end body joins to the peripheral body and extends radially towards the nozzle axis. The effusion passage extends through the cap to intersect at least one of the peripheral body and the end body.