Sonic Flow Control Valve Curved Passage Pressure Recovery
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Solution Overview
Problem
Existing gas turbine fuel control valves face challenges in efficiently managing fuel flow at high velocities and pressure ratios, leading to suboptimal pressure recovery and potential pressure loss due to orthogonal flow orientations and circular cross-sectional passages.
Innovation Solution
A flow control valve design featuring a valve body with a converging inlet passage, a narrowing nozzle, and a diverging diffuser passage, combined with a moveable valve plug and actuator, which accelerates and decelerates gas flow through a sonic nozzle, maintaining supersonic velocities while minimizing pressure drop and maximizing pressure recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the inlet flow enters the valve transverse or orthogonal to the outlet flow, then the valve can control gas flow for turbine applications, but pressure loss increases and pressure recovery is suboptimal
Solution Approach 1:
The patent employs curved flow passages throughout the valve body, including a curved inlet passage that transitions flow from axial to radial direction, and a curved outlet passage that transitions flow back to axial direction. These curved passages eliminate sharp angles and orthogonal intersections, allowing smooth flow transitions that reduce turbulence and pressure loss while maintaining effective flow control capability.
2Measurement precision
If the valve provides sonic flow through the nozzle throat, then flow control precision is improved, but pressure recovery is reduced due to high velocity flow
Solution Approach 1:
The valve flow path is segmented into distinct functional zones: a converging section that accelerates flow to sonic velocities at the throat for precise control, followed by a diverging section that decelerates flow and recovers pressure. This segmentation allows the valve to achieve both sonic flow precision and pressure recovery by treating these as separate sequential processes rather than conflicting requirements.
Solution Approach 2:
The patent utilizes changes in flow parameters through carefully designed passage geometries. The converging passage transforms pressure energy to kinetic energy, achieving sonic velocities at the throat. The subsequent diverging passage transforms kinetic energy back to pressure energy, recovering pressure downstream. This parameter transformation sequence enables both precise sonic flow control and effective pressure recovery.
3Speed
If the valve uses a converging flow path with reducing cross-sectional area, then flow velocity increases for sonic flow control, but pressure drop increases
Solution Approach 1:
The converging passage is designed with a curved, gradually narrowing cross-section rather than a straight abrupt reduction. This curved geometry allows flow to accelerate smoothly to high velocities while minimizing flow separation and turbulence that would cause excessive pressure drop. The smooth curvature maintains attached flow throughout the convergence, reducing energy losses.
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 design achieves high pressure recovery and maintains constant gas throughput across the valve, independent of upstream pressure, with the ability to control flow rates near Mach 1, reducing pressure loss and optimizing fuel delivery in gas turbines.
Implementation Method 1
The inlet passage comprises a narrowing nozzle passage upstream of the valve throat having an uninterrupted surface generally converging toward the valve throat
Implementation Method 2
The valve is described as providing sonic flow through the nozzle throat per pressure ratios (P1/P2) at or above approximately 1.04
Implementation Method 3
The outlet passage comprises a widening diffusor passage downstream of the valve throat having a surface generally diverging away from the valve throat
Data Source
AI summary
A flow control valve comprising a valve body having a valve throat, a narrowing nozzle passage upstream of the valve throat, a valve member having an outer narrowing surface and movable relative to the valve body to meter flow through the valve throat, a widening diffusor passage, a widening passage downstream of an inlet port and upstream of the narrowing nozzle passage, and the widening portion widening from a first section having a first cross-sectional area that is equal to or greater than the cross-sectional area of the inlet port to a second section downstream a distance from the first section and having a second cross-sectional area that is greater than the cross-sectional area of the first section of the widening portion.