Globe Valve Flow Channel Geometry for Low-Swirl Flow Control
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Solution Overview
Problem
Conventional globe valves experience increased flow resistance and swirl formation due to curved inlet designs, leading to undefined flow resistances and pressure discrepancies, which can result in suboptimal fluid flow and measurement inaccuracies.
Innovation Solution
A globe valve with a flow channel featuring a circular inlet opening and an oval-shaped cross-section that gradually decreases in size, reducing deflection and friction, and maintaining a consistent cross-sectional area downstream, thereby minimizing swirl formation and flow resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the inlet cross section is enlarged continuously up to the throttle element to counteract flow resistance, then the flow through factor (Kv-value) is improved, but the construction space and device complexity increase
Solution Approach 1:
The flow channel is divided into distinct sections with different cross-sectional characteristics: a first section with gradually decreasing surface size and a second section with substantially constant surface size. This segmentation allows optimization of flow characteristics in each section without requiring continuous enlargement throughout the entire channel, thus improving flow through factor while controlling construction space.
Solution Approach 2:
Different sections of the flow channel are given different geometric properties tailored to their specific functional requirements. The first section has a decreasing surface size to manage flow separation, while the second section maintains constant surface size to minimize friction losses. This local optimization achieves high productivity without excessive construction space.
2Ease of operation
If a curved inlet design is used to guide flow to the passage opening, then the flow direction is improved, but flow resistance and swirl formation increase
Solution Approach 1:
The flow channel utilizes controlled curvature in the first section to guide flow direction toward the passage opening, while the second section provides a straighter path to minimize swirl formation. This strategic use of curvature achieves effective flow direction control while reducing energy losses compared to continuously curved designs.
3Object-generated harmful factors
If the flow channel surface size decreases gradually from inlet to passage, then swirl flows are reduced, but the flow cross section and productivity may be limited
Solution Approach 1:
The flow channel is segmented into two distinct sections: the first section with decreasing surface size to suppress swirl formation, and the second section with constant surface size to maintain high flow capacity. This segmentation resolves the contradiction by allowing swirl reduction in the first section while preserving productivity in the second section.
Solution Approach 2:
The flow channel design ensures continuous beneficial flow characteristics from inlet to passage opening. The first section continuously decreases surface size to eliminate swirls, and the second section maintains constant surface size to sustain high flow throughput, ensuring continuous useful action throughout the entire flow path.
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 ensures reliable flow control with reduced reverse flows and swirls, maintaining the valve's Kv value without increasing construction space, and allows for precise flow measurements by minimizing the influence of the valve member and rod on the flow behavior.
Implementation Method 1
The process fluid flow separates after about 2⁄3 of the way to the passage opening. The separation can take place earlier or later depending on the flow velocity and the pressure difference.
Implementation Method 2
In order to counteract an increase of the flow resistance caused by the curved area in the inlet and by the friction losses at the tube wall
Implementation Method 3
The separation can take place earlier or later depending on the flow velocity and the pressure difference.
Data Source
AI summary
A globe valve (e.g. Flow-To-Open valve) can include an inlet opening with a circular shaped opening cross section defining a valve axis, a globe valve member movable in a vertical direction transversely to the valve axis and connectable, via a valve rod, to an actuator for actuating the globe valve member, and a passage opening with a circular-shaped passage opening cross section. The globe valve member closes the passage opening at a lowest actuating position, in the vertical direction, and a flow channel extending from the inlet opening to the passage opening defines a flow cross section. The surface size of the flow cross section decreases in a first section from the inlet opening, in a flow direction, to a transition point. The flow cross section, in the first section, is continuously oval shaped and the first section of the flow channel is continuously inclined downwards in the vertical direction.