Magnetically Latched Staging Fuel Valve to Prevent Sticking
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Solution Overview
Problem
Existing fuel flow valves in gas turbine engines face challenges in switching between pilot and main fuel flows due to low actuation pressure, leading to sticking issues and increased complexity when using electromagnetic actuation, especially in high-temperature environments.
Innovation Solution
A staging fuel valve with a magnetically actuated piston and coil arrangement that allows for fluid communication between pilot and main fuel inlets and outlets, utilizing permanent magnets for latching and electromagnetic assistance to prevent sticking, and a tapered piston head for actuation assistance from fuel pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic actuation is added to address low actuation pressure, then the valve can be actuated reliably, but the valve becomes more complicated and larger
Solution Approach 1:
The patent combines electromagnetic actuation with hydraulic actuation into a single integrated piston system. The piston receives both electromagnetic force from the coil and hydraulic force from fuel pressure, merging two actuation mechanisms into one unified structure that switches between pilot and main fuel flows without requiring separate valve components.
Solution Approach 2:
The piston serves multiple functions: it acts as both an electromagnetic actuator response element and a hydraulic control element. The same piston that responds to electromagnetic coil activation also responds to hydraulic pressure from fuel flow, providing universal actuation capability across different operating conditions without requiring additional components.
2Device complexity
If hydraulic latching is used to simplify valve actuation, then the valve structure is simpler, but the valve may stick in closed or open position due to fuel lacquering in high temperature environments
Solution Approach 1:
The electromagnetic coil acts as an intermediary mechanism that provides active control to prevent sticking. While the hydraulic system provides the basic latching function, the electromagnetic coil intervenes when needed to actively actuate the piston, breaking any potential sticking caused by fuel lacquering in high temperature environments.
Solution Approach 2:
The system changes the actuation parameter from purely hydraulic to a combination of electromagnetic and hydraulic forces. By introducing electromagnetic force as an additional actuation parameter, the system can overcome static friction and fuel lacquering effects that cause sticking in purely hydraulic systems operating in high temperature environments.
3Ease of operation
If a larger valve is designed to handle low actuation pressure, then the valve can be actuated by fuel supply pressure change alone, but the valve size increases
Solution Approach 1:
The patent replaces purely mechanical/hydraulic actuation with an electromagnetic field-based actuation system. The electromagnetic coil generates magnetic force to actuate the piston directly, eliminating the need for large mechanical components that would be required to amplify low fuel supply pressure changes for valve actuation.
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 provides a simple and reliable actuation mechanism that reduces the risk of valve sticking, allowing for efficient fuel scheduling and operation in high-temperature environments by leveraging magnetic forces and fuel pressure for actuation and latching.
Implementation Method 1
the valve housing comprises a coil arranged to provide, when energised, a magnetic force to actuate the piston between the first and second positions
Implementation Method 2
the piston comprises a magnet assembly and the valve housing comprises a coil arranged to provide, when energised, a magnetic force to actuate the piston
Implementation Method 3
a pressure of the fuel flow from the second inlet to the second outlet tends to cause the piston to further actuate towards the second position
Data Source
AI summary
A fuel flow valve, for example for use in supplying fuel to a gas turbine engine. Example embodiments disclosed include a staging fuel valve (300), comprising: a valve housing (301) having first and second fuel inlets (306, 307) and first and second fuel outlets (305, 308); a piston (302) slidably mounted within a chamber (303) in the valve housing (301) and being moveable between a first position in which the first inlet (306) is in fluid communication with the first outlet (305) while the second inlet (307) and second outlet (308) are blocked, and a second position in which the second inlet (307) is in fluid communication with the second outlet (308). The piston (302) comprises a magnet assembly (312) and the valve housing (301) comprises a coil (313) arranged to provide, when energised, a magnetic force to actuate the piston (302) between the first and second positions.