Three-Way Fuel Valve Purging to Prevent Gas Turbine Coking
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Solution Overview
Problem
Residual liquid fuel in gas turbine engines' liquid fuel supply systems can oxidize and decompose due to increased temperatures near combustors, leading to coke formation, which clogs fuel lines and valves, necessitating frequent maintenance.
Innovation Solution
A three-way valve with a purge gas inlet and drain ports, along with a fitting that minimizes dead space, is used to channel purge gas through the system, removing residual liquid fuel and preventing coke formation by ensuring efficient drainage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the liquid fuel supply system is purged with gas to remove residual liquid fuel, then coke formation is reduced, but some residual liquid fuel remains in cavities formed by valve and fitting alignment
Solution Approach 1:
The patent applies preliminary action by positioning the drain port to drain liquid fuel from the purge gas chamber before purge gas is introduced. This preliminary drainage configuration ensures that when purging occurs, liquid fuel is already removed from critical areas, preventing it from becoming stagnant and forming coke deposits in cavities created by valve and fitting alignments
Solution Approach 2:
The patent extracts the drainage function from the standard purge process by adding a dedicated drain port that separately removes liquid fuel from the purge gas chamber. This extraction allows liquid fuel to be removed through the drain port while purge gas flows through the purge gas inlet, preventing liquid fuel accumulation in cavities without requiring modification of the purge gas path
2Device complexity
If valves and fittings are aligned in the liquid fuel supply system, then device complexity is reduced, but cavities are formed that contain residual liquid fuel susceptible to coking
Solution Approach 1:
The patent introduces an intermediary drainage path through the drain port that mediates between the simple valve and fitting alignment and the harmful cavity formation. The drain port acts as an intermediary element that provides a dedicated escape route for liquid fuel from cavities created by the aligned components, allowing the simple alignment to be maintained while preventing coking
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 solution effectively reduces coke deposits, enhancing the reliability and efficiency of gas turbine engines by preventing coking and extending maintenance intervals.
Implementation Method 1
at least some known gas turbine engines circulate purge gas through the liquid fuel supply system. For example, at least some known systems purge the liquid fuel lines with a gas, such as nitrogen, to enable the remaining liquid fuel and/or gas to be drained from the liquid fuel supply system
Implementation Method 2
The increased operating temperature of the portion of the liquid fuel supply system adjacent to the combustors may cause oxidation and/or partial decomposition of the residual liquid fuel in the liquid fuel supply system, thereby producing coke in the fuel lines and/or valves in a process known as 'coking.'
Implementation Method 3
The increased operating temperature of the portion of the liquid fuel supply system adjacent to the combustors may cause oxidation and/or partial decomposition of the residual liquid fuel in the liquid fuel supply system, thereby producing coke in the fuel lines and/or valves
Data Source
AI summary
A three-way valve for a liquid fuel supply system includes a housing defining a liquid fuel inlet, a purge gas inlet, and at least one drain port. The liquid fuel inlet is sized to receive liquid fuel therethrough for selectively channeling the liquid fuel to a combustor of a gas turbine engine. The purge gas inlet is sized to receive purge gas therethrough for selectively purging liquid fuel from said three-way valve. The at least one drain port is oriented to selectively channel liquid fuel from said three-way valve when purge gas is purging liquid fuel from said three-way valve.