Multi-Phase Flow Measurement Using Break-Away Edge Pressure Taps
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Solution Overview
Problem
Existing methods for determining the mass fraction of the gas phase in multi-phase media in measuring tubes suffer from reduced measurement accuracy and require large, complex designs, particularly when using differential pressure measurements.
Innovation Solution
A method utilizing a measuring tube with a break-away edge and at least three pressure tap points, where the positions of these tap points are strategically arranged to maximize sensitivity, allowing for the determination of mass fraction and mass flow rate based on specific pressure drop ratios, with the first pressure tap point upstream and the second and third downstream, positioned near pressure minima and maxima respectively, to calculate the mass fraction and mass flow rate as a function of these pressure drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If differential pressure measurements are used to determine gas phase mass fraction in multi-phase media, then measurement capability is achieved, but measurement accuracy is reduced and device size increases
Solution Approach 1:
The patent applies local quality by strategically positioning pressure tap points at specific locations with distinct flow characteristics - one upstream of the break-away edge and two downstream at different positions. Each tap point measures pressure in a localized region with different flow properties, and the combination of these localized measurements enables accurate gas phase mass fraction determination while maintaining a compact device design.
2Measurement precision
If pressure tap points are positioned to maximize sensitivity for mass fraction determination, then measurement precision improves, but device design becomes more complex
Solution Approach 1:
The patent employs parameter changes by utilizing the natural variation in pressure parameters at different locations along the measuring tube. By positioning tap points to capture pressure values at specific locations (upstream and downstream of the break-away edge), the system exploits the changing pressure parameters caused by the break-away edge's influence on flow to maximize sensitivity for gas phase mass fraction determination.
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 approach enhances measurement accuracy and reduces the size of the measuring assembly by using strategically placed pressure tap points to determine the mass fraction and mass flow rate of the gas phase, independent of flow rate, thereby improving sensitivity and precision.
Implementation Method 1
determining a first pressure drop between a first and second of the at least three pressure tap points which are each impinged by the flowing medium; determining a second pressure drop between two pressure tap points
Data Source
AI summary
A method for determining a gas phase mass fraction or mass flow rate of a multi-phase medium flowing in a measuring tube, which includes a break-away edge exposed to the flow and three pressure taps, each influenced differently by the break-away edge, the method including: determining a first pressure drop between the first and second pressure taps; determining a second pressure drop between the third pressure tap and one of the first or second pressure taps; and determining the mass fraction or mass flow rate of the gas phase from the first and second pressure drops, the first pressure tap arranged upstream of the break-away edge and both the second and third pressure taps downstream thereof, one normal vector substantially axis-parallel to the second pressure tap and one normal vector perpendicular to the third pressure tap, the second pressure tap point positioned at or close to a pressure minimum.