Fuel Nozzle Metering Valve With Fixed High-Pressure Flow Geometry
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Solution Overview
Problem
Conventional fuel nozzles for jet engines experience flow variability due to geometric variations and valve displacement non-uniformity, leading to inconsistent fuel flow rates, especially at higher power settings, which affects combustor and turbine durability and reliability.
Innovation Solution
The design incorporates a spool and retainer mechanism within the fuel nozzle, where a spring-loaded spool moves within a valve liner, and a stepped portion of the retainer limits spool displacement, maintaining fixed flow geometry at all pressure points, reducing flow rate variations by ensuring predictable fuel flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a spring-loaded valve is actuated with increasing fuel flow pressure to open and displace, then the valve can deliver fuel across a wide flow range, but flow variability increases due to valve displacement non-uniformity and hysteresis
Solution Approach 1:
The valve system transitions from a fully dynamic spring-loaded valve to a hybrid system where the valve is dynamically actuated at low pressures and becomes fixed at high pressures. The valve body can slide within the valve liner to expose different flow ports based on pressure, creating a dynamic-lowpressure/fixed-high-pressure configuration that reduces flow variability while maintaining wide flow range capability
Solution Approach 2:
The system changes the physical state of the valve from movable to fixed by using pressure to slide the valve body, thereby changing the flow geometry from variable to fixed. This parameter change (valve position) as a function of pressure eliminates hysteresis and displacement non-uniformity at high pressures, improving flow tolerance
2Ease of operation
If the valve displacement is unimpeded throughout the full range of imposed fuel flow pressure, then the valve can respond to all pressure values, but flow rate variations increase due to geometric variation and displacement non-uniformity
Solution Approach 1:
The pressure range is segmented into two distinct zones: low pressure where the valve is free to move and respond dynamically, and high pressure where the valve is constrained to a fixed position. This segmentation allows the system to optimize for different operating conditions separately, maintaining responsiveness where needed while ensuring precision where required
3Adaptability or versatility
If conventional fuel nozzles are used with spring-loaded valves, then the system can operate across varying pressure conditions, but flow tolerance variations increase by up to 42% at high inlet pressures
Solution Approach 1:
The valve system transitions from a fully dynamic spring-loaded valve to a hybrid system where the valve is dynamically actuated at low pressures and becomes fixed at high pressures. The valve body can slide within the valve liner to expose different flow ports based on pressure, creating a dynamic-lowpressure/fixed-high-pressure configuration that reduces flow variability while maintaining wide flow range capability
Solution Approach 2:
The system changes the physical state of the valve from movable to fixed by using pressure to slide the valve body, thereby changing the flow geometry from variable to fixed. This parameter change (valve position) as a function of pressure eliminates hysteresis and displacement non-uniformity at high pressures, improving flow tolerance
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
This solution significantly reduces flow tolerance variations by up to 42% at high inlet pressures, ensuring consistent and reliable fuel delivery, enhancing the durability and reliability of jet engine combustors and turbines.
Implementation Method 1
The check valve is biased in a closed position... The valve is opened when the spool slides within the valve liner... a spring-loaded spool moves within a valve liner
Implementation Method 2
The retainer has a stepped portion configured to abut an end of the valve liner at a fuel flow pressure below the expected maximum fuel flow pressure
Data Source
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AI summary
A fuel nozzle metering valve that includes a spool having an inlet port and an outlet flow port, and a retainer assembled to one end of the spool. A valve liner houses a portion of the spool. The spool is configured to move back and forth within the valve liner. The metering valve is biased in a closed position in which the outlet flow port is disposed entirely within the valve liner. The valve is opened when the spool slides within the valve liner such that some portion of the outlet flow port extends beyond an end of the valve liner. The retainer has a stepped portion configured to abut an end of the retainer at a fuel flow pressure below the expected maximum fuel flow pressure to be used in the fuel nozzle metering valve.