Reduced Bore Vortex Flowmeter Stepped Intake Design
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Solution Overview
Problem
Vortex flowmeters in reduced bore sizes experience decreased linearity and performance due to low fluid velocity, which is exacerbated by the need for oversized conduits to accommodate future demand, leading to inaccuracies in fluid flow measurements.
Innovation Solution
A reduced bore vortex flowmeter with a tubular fluid inlet featuring a stepped inner wall, where the first wall portion is at a first angle and the second wall portion is at a greater angle, forming a concave axial cross-section, coupled with a shedder within the central bore, which enhances flow disruption and measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a smaller sized flowmeter is installed into a large size conduit, then the fluid velocity increases, but the linearity of measurement decreases
Solution Approach 1:
The inlet structure is designed with different wall portions having different angles (first wall portion at a first angle, second wall portion at a second angle greater than the first angle) to create a stepped inner wall configuration. This local differentiation of geometric properties optimizes flow characteristics at specific locations within the inlet, allowing the flowmeter to maintain measurement linearity while operating in reduced bore applications.
Solution Approach 2:
The stepped inner wall configuration with concave axial cross-section creates a specific flow pattern that reduces velocity profile errors. The curved or angled surfaces guide the fluid flow in a controlled manner, transforming the velocity distribution to improve measurement accuracy in reduced bore conditions.
2Speed
If the bore size is reduced to increase fluid velocity, then the operating range is reduced
Solution Approach 1:
The differentiated inlet structure with multiple wall portions at different angles creates optimized flow conditions that extend the usable operating range. By locally modifying the flow characteristics at the inlet, the flowmeter can maintain performance across a broader range of operating conditions despite the reduced bore size.
3Measurement precision
If a stepped inner wall configuration is implemented, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The inlet structure is divided into distinct wall portions (first wall portion and second wall portion) with different angular configurations. This segmentation allows each portion to perform a specific function in optimizing flow characteristics, achieving improved measurement accuracy through modular geometric design rather than a complex monolithic structure.
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 stepped inlet design provides high accuracy and linearity across a wide range of size reductions, maintaining measurement precision even at low Reynolds numbers, reducing velocity profile errors and pressure variations, and improving the K factor consistency.
Implementation Method 1
a first wall portion disposed upstream of a second wall portion, the second wall portion having a flow disrupter configured to disrupt flow of the process fluid relative to the flow of the fluid upstream thereof
Implementation Method 2
A shedder is disposed within the central bore... the frequency of vortices shed by the shedder is measured
Data Source
AI summary
A reduced bore vortex flowmeter and flowmeter body includes a fluid inlet couplable in series to an upstream portion of a fluid flow conduit. The inlet fairs into a central bore having a transverse cross-sectional dimension less than that of the conduit, and which houses a shedder. The central bore is communicably coupled to a fluid outlet couplable to a downstream portion of the conduit. The inlet has a stepped or structured inner wall, including a first wall portion disposed at first angle to the downstream direction, and a second wall portion disposed at a second angle to the downstream direction. The second angle is greater than the first angle, so that the first and second wall portions form a substantially concave axial cross-section. The stepped intake improves linearity of flow measurements by reducing velocity profile errors and/or extending contracted flow to the shedder over a relatively wide flow range.