Multiphase Flow Tomography with Pipe-Wall Capacitance Removal
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Solution Overview
Problem
Existing multiphase flow measurement technologies face challenges in accurately determining phase distribution and velocity profiles due to varying flow regimes, with electrical tomography methods often producing qualitative and indirect results due to pipe-wall capacitance effects.
Innovation Solution
A tomography system using a processor to compute quantitative values of permittivity, conductivity, and magnetic permeability from capacitance, conductance, and admittance measurements, allowing for robust determination of multiphase fluid properties and phase holdups, with sensors distributed around the duct to measure these properties and a method for normalizing measurements to remove pipe-wall capacitance effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrical tomography methods are used to measure multiphase flow, then phase distribution and velocity profiles can be obtained, but the results are qualitative and indirect due to pipe-wall capacitance effects
Solution Approach 1:
The patent extracts and removes the pipe-wall capacitance effect from the measurement system by using a normalization model that separates the wall capacitance component from the total measured capacitance, allowing the fluid capacitance to be determined independently and accurately
Solution Approach 2:
The patent transforms the measurement parameters from raw capacitance values to normalized capacitance values that are corrected for wall capacitance effects, and further to fluid permittivity values, changing the parameter representation to eliminate the harmful wall capacitance influence
2Ease of operation
If traditional capacitance measurement normalization models are used, then processing can be simplified, but pipe-wall capacitance effects cannot be removed and only indirect qualitative results are obtained
Solution Approach 1:
The patent introduces a normalization model as an intermediary processing step that acts as a bridge between raw capacitance measurements and fluid property determination, systematically removing wall capacitance effects while maintaining processing efficiency
Solution Approach 2:
The patent performs preliminary normalization of the capacitance measurements to remove wall capacitance effects before proceeding to fluid property calculation, preparing the data in advance to ensure accurate quantitative results
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
Enables accurate, quantitative reconstruction of multiphase flow properties and phase fractions, overcoming the limitations of indirect and qualitative results from previous methods, providing precise measurements of permittivity, conductivity, and holdups in multiphase flows.
Implementation Method 1
measuring properties representative of capacitance, conductance, inductance or admittance
Implementation Method 2
measuring properties representative of capacitance, conductance, inductance or admittance
Implementation Method 3
compute quantitative values of permittivity, conductivity, magnetic permeability and/or complex-permittivity/-conductivity
Data Source
AI summary
A tomography system for determining properties of flowing multiphase fluid, comprising a duct having a duct wall and interior space within the duct wall for carrying a flow of the multiphase fluid and a plurality of sensors, which are electrodes or coils, at positions distributed around the duct wall on a planar cross section through the duct, wherein the sensors (electrodes or coils) are used for making a plurality of measurements of electrical or magnetic properties through the duct wall and the multiphase fluid; and a processor is used to receive measurement data from the sensors and to compute from the measured properties to derive quantitative values of at least one property selected from permittivity, conductivity, magnetic permeability and complex-conductivity of the multiphase fluid independent of effects external to the fluid flow, such as effects of the duct walls and the geometry of the positioning of the sensors (electrodes or coils).