Cooled Fuel Injector Sleeve for Gas Turbine Engine
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Solution Overview
Problem
Gas turbine engine fuel injectors face issues with coke formation due to high fuel temperatures, leading to narrowed fuel openings, uneven fuel burn, and increased maintenance requirements, as conventional designs struggle to effectively reduce fuel heating rates within the injector conduit.
Innovation Solution
A cooling system for the fuel injector includes a heat exchanger to cool diffuser case air, a sleeve surrounding the fuel conduit, and a distribution apparatus to direct cooled air to the nozzle tip, reducing the heating rate of fuel and minimizing coke formation by maintaining lower wetted wall temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional heat shields with static air gaps are used to insulate the fuel conduit, then the structure is simple and easy to manufacture, but the fuel heating rate is insufficient leading to coke formation
Solution Approach 1:
The patent introduces a cooling fluid sleeve as an intermediary component between the hot diffuser case air and the fuel conduit. This sleeve carries cooling air that flows along the fuel conduit, acting as a thermal mediator to reduce heat transfer to the fuel without requiring direct contact between cooling and fuel streams, thereby maintaining reliability while managing system complexity
Solution Approach 2:
The patent employs pneumatic cooling by introducing cooling air through the sleeve and along the fuel conduit. This uses fluid flow (air) to manage thermal conditions, replacing or supplementing static thermal insulation with dynamic fluid-based cooling, which improves heat rejection effectiveness while adding controlled complexity to the system
2Productivity
If the diffuser case air temperature is increased to improve engine performance, then engine efficiency improves, but fuel heating rate increases leading to increased coking
Solution Approach 1:
The patent applies local quality by providing targeted cooling specifically at the fuel conduit location within the hot diffuser case environment. The cooling sleeve and associated airflow are positioned to create a localized cool zone around the fuel conduit, allowing the surrounding diffuser case air to remain hot for engine performance while the fuel conduit area maintains lower temperatures to prevent coking
Solution Approach 2:
The patent implements preliminary anti-action by introducing cooling air before the fuel undergoes significant heating. The cooling sleeve positions cooling airflow upstream and along the fuel conduit path, preemptively counteracting the heat transfer from the hot diffuser case air before it can cause fuel temperature rise and coke formation
3Reliability
If cooling air is introduced through the sleeve to reduce fuel heating, then coke formation is minimized, but the system complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies the nested doll principle by placing the cooling sleeve inside or around the diffuser case structure, and positioning the fuel conduit within the cooling sleeve's flow path. This nested arrangement integrates multiple functions (structural support, thermal management, fluid delivery) into concentric or layered components, improving reliability while attempting to streamline manufacturing through integrated design
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 cooling system effectively reduces fuel heating rates, minimizing coke deposition and performance degradation, thereby enhancing the reliability and efficiency of the fuel injector system.
Implementation Method 1
a heat exchanger for cooling hot diffuser case air
Implementation Method 2
a heat exchanger constructed and arranged to receive hot diffuser case air and expel cooled diffuser case air
Implementation Method 3
a sleeve surrounding at least in part a fuel conduit of a fuel injector... an inlet of the sleeve for receiving cooled diffuser case air
Implementation Method 4
to reduce the heat transfer rate within the diffuser case module to the fuel
Implementation Method 5
reducing the heating rate of fuel and minimizing coking
Implementation Method 6
flow the cooled diffuser case air to a turbine section of the engine for cooling of the turbine section
Data Source
AI summary
A cooling system for a fuel injector system of a gas turbine engine has a heat exchanger for cooling a portion of diffuser case air and then routing the cooled diffuser case air through a sleeve that surrounds a fuel injector conduit located in at least the diffuser case plenum for minimizing fuel heat-up rates in the conduit. By minimizing fuel temperatures within the injector conduit, coking accumulation is thereby eliminated or reduced.