Aircraft Minimum Pressure Valve for Stable Transient Fuel Flow
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Solution Overview
Problem
Existing fuel systems in gas turbine engines face challenges in maintaining minimum pressure levels during transient conditions caused by flow divider valve actuation, leading to fuel flow disruptions and combustor acoustic noise.
Innovation Solution
A minimum pressure valve (MPV) with a unique piston design and biasing mechanism that compensates for transient pressure changes, ensuring stable fuel flow by equalizing forces on piston heads to prevent unwanted opening or closing of fuel ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a minimum pressure valve is provided to maintain minimum pressure during transient conditions, then fuel flow stability is improved, but device complexity increases due to additional valve components
Solution Approach 1:
The valve body is divided into multiple segments (first segment, second segment, center segment) with different diameters, creating distinct chambers for different functions. This segmentation allows the single valve to handle multiple pressure control functions simultaneously, improving fuel flow stability during transient conditions while maintaining a compact structure.
Solution Approach 2:
The patent introduces a radial dimension by creating inner walls within the valve body that extend radially inward, forming multiple chambers. This dimensional approach allows pressure control in different radial zones, enabling the valve to maintain minimum pressure during transient conditions without requiring multiple separate valves.
2Object-affected harmful factors
If flow divider valve actuates to switch between equalized and unequalized pressure modes, then combustor acoustic noise is reduced, but transient pressure conditions disrupt minimum pressure valve operation
Solution Approach 1:
The valve design includes counterbalancing forces acting on the piston head from opposite directions (first force from first chamber pressure, second force from second chamber pressure). During transient conditions from flow divider valve actuation, these counterbalancing forces maintain equilibrium, preventing unwanted valve opening or closing and ensuring continuous minimum pressure maintenance despite noise-reducing pressure transitions.
Solution Approach 2:
The patent utilizes pressure parameter changes in different chambers to control valve operation. By maintaining pressure differentials between chambers and adjusting piston head surface areas, the valve adapts to transient pressure conditions while continuing to enforce minimum pressure requirements, allowing the system to switch between equalized and unequalized modes without losing pressure control.
3Stability of the object's composition
If piston head surface areas are made equal to balance forces, then pressure control stability is improved, but valve responsiveness to actual fuel flow needs is reduced
Solution Approach 1:
The patent applies different surface area ratios to different piston head portions (first piston head vs. second piston head) based on their specific functional requirements. The first piston head has a larger surface area to counteract higher pressures from the first chamber, while the second piston head has a smaller surface area appropriate for the second chamber. This localized differentiation maintains force balance for stability while preserving necessary response speed.
Solution Approach 2:
The valve design incorporates dynamic pressure balance where the piston head surface areas are configured to create equalizing forces under normal operating conditions. During transient conditions, the system dynamically adjusts chamber pressures to maintain force equilibrium, allowing the valve to respond appropriately to fuel flow demands while maintaining overall pressure control stability.
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 MPV stabilizes fuel flow, reducing combustor acoustic noise and maintaining consistent pressure, thereby ensuring reliable engine operation during transient conditions.
Implementation Method 1
a biasing member disposed in the first segment, seated between the first piston head and the first outer wall
Implementation Method 2
the biasing member is a compression spring
Data Source
Figure 1
Figure 2
AI summary
A valve having a first segment (220) between a first outer wall (220A) and a first inner wall (220B) and has a first outer port (225A) near the first outer wall and a side port (225B) between the first inner and outer walls; a second segment (230) between a second outer wall (230A) and a second inner wall (230B) and has a second outer port (235A) near the second outer wall; a center segment (240) between the first and second inner walls, and a center port (242); and a piston (245) within the valve, having: a first piston head (250) in the first segment that slides to block and unblock the side port; a second piston head (260) in the second segment that slides between the second inner and outer walls, the second piston head having a surface area that is the same as the first piston head; and a shaft (270) connecting the first and second piston heads.