Multi-tube Thermal Fuse for Nozzle Flashback Protection
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Solution Overview
Problem
Gas turbine engines face challenges with auto-ignition, flashback, and flame holding in pre-mixing apparatuses, which can damage equipment and increase NOx emissions, necessitating effective protection mechanisms.
Innovation Solution
A thermal fuse system is integrated into the pre-mixing apparatus, featuring a material that melts upon ignition, diverting fuel from the fuel feed opening to a bypass opening to prevent further damage and maintain engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If pre-mixing is used to reduce NOx emissions, then NOx output is reduced, but auto-ignition, flashback and flame holding may occur causing equipment damage
Solution Approach 1:
The thermal fuse is pre-installed on the pre-mixing apparatus tube exterior surface before operation. This preliminary protective measure ensures that if auto-ignition or flashback occurs, the fuse will immediately respond by melting and closing the bypass opening to divert fuel, preventing equipment damage while maintaining the NOx reduction benefits of pre-mixing
Solution Approach 2:
The thermal fuse acts as an intermediary protective element between the pre-mixing apparatus and potential harmful effects. When the tube temperature exceeds the fuse's melting point, the fuse material melts and closes the bypass opening, mediating the fuel flow to prevent direct contact of flame with the apparatus while allowing continued operation
2Reliability
If thermal fuse is added to protect against flashback, then equipment protection is improved, but device complexity increases
Solution Approach 1:
The thermal fuse is designed as a simple, inexpensive, single-use protective element. It consists of a fuse member with a bypass opening that is either pre-formed or created by melting the fuse material. Once activated, the fuse permanently closes the bypass opening, but this simple disposable approach provides effective protection without adding complex reusable safety systems
Solution Approach 2:
The thermal fuse operates by changing its physical state from solid to liquid when the tube temperature exceeds the fuse material's melting point. This parameter change (temperature-triggered phase transition) automatically closes the bypass opening to divert fuel, providing a simple yet effective protection mechanism that responds directly to the thermal conditions without requiring complex control systems
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 thermal fuse system effectively mitigates flame holding and flashback events by diverting fuel, reducing damage to the nozzle and maintaining engine operability until repairs can be made, while also controlling NOx emissions through precise fuel-air mixing.
Implementation Method 1
at least one thermal fuse disposed on an exterior surface of at least one tube, the at least one thermal fuse including a material that will melt upon an ignition of fuel within the at least one tube
Data Source
AI summary
A protection system for a pre-mixing apparatus for a turbine engine, includes: a main body having an inlet portion, an outlet portion and an exterior wall that collectively establish a fuel delivery plenum; and a plurality of fuel mixing tubes that extend through at least a portion of the fuel delivery plenum, each of the plurality of fuel mixing tubes including at least one fuel feed opening fluidly connected to the fuel delivery plenum; at least one thermal fuse disposed on an exterior surface of at least one tube, the at least one thermal fuse including a material that will melt upon ignition of fuel within the at least one tube and cause a diversion of fuel from the fuel feed opening to at least one bypass opening. A method and a turbine engine in accordance with the protection system are also provided.