Flanged Reducer Vortex Flowmeter Stability
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Solution Overview
Problem
Reducer vortex flowmeters with larger measurement bore diameters experience reduced accuracy and unstable signals due to a shorter length from the bluff body to the first expansion, leading to vortex shedding instability, especially when the diameter ratio of the flow passage to the vortex wavelength is less than 1.
Innovation Solution
The flowmeter design includes a longer constant diameter section from the bluff body to the first expansion, ensuring the length exceeds the vortex wavelength, thereby stabilizing vortex shedding and improving signal accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the measurement bore diameter is increased to reduce power loss, then the Reynolds number is reduced, but the length from bluff body to first expansion becomes too short, causing vortex shedding instability
Solution Approach 1:
The patent changes the geometric parameters of the flow passage, specifically increasing the length from the bluff body to the first expansion point and optimizing the diameter ratio, to ensure stable vortex shedding while maintaining larger bore diameter for reduced power loss
2Quantity of substance
If the measurement bore diameter is increased to accommodate larger pipe sizes, then the flow velocity range is reduced, but the vortex wavelength becomes comparable to or larger than the passage length, causing measurement inaccuracies
Solution Approach 1:
The patent optimizes the diameter ratio between the measurement section and the expansion section, and increases the length parameter L to exceed the vortex wavelength, ensuring accurate flow measurements across a wider range of pipe sizes and flow rates
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 design enhances the stability and accuracy of flow measurements by maintaining a ratio of length to vortex wavelength greater than or equal to 1, reducing noise and missed pulses, and maintaining signal stability across a wider range of flow rates.
Implementation Method 1
the operating principle of a vortex flowmeter is based on a vortex shedding phenomenon known as the von Karman effect. As fluid passes a bluff body, it separates and generates vortices that are shed alternately along and behind each side of the bluff body
Implementation Method 2
The operating principle of a vortex flowmeter is based on a vortex shedding phenomenon known as the von Karman effect. While the frequency of vortex generation is essentially proportional to fluid velocity
Data Source
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AI summary
A flanged vortex flowmeter 10A is connected to a flanged piping system 12, 14 that has a diameter DP larger than the diameter DM of the measurement section 22 of the vortex flowmeter. The vortex flowmeter 10A has an inlet flange 20 that reduces diameter from the inlet to the measurement section. A bluff body 26 positioned in the measurement section 22 produces vortices that alternate at a frequency proportional to the flow rate of fluid through the flowmeter 10A. A length LM from inception of vortex shedding at the bluff body 26 to a first expansion of the flow passage downstream of the bluff body 26 is greater than a vortex wavelength λ of the vortices produced by the bluff body 26.