Coaxial Resonator Mode Separation for Salinity Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multiphase fluid flow measurement systems face challenges in accurately determining salinity and water content due to interference from degenerate resonance modes, which affect the measurement of conductivity and Q-factor in oil and gas production processes.
Innovation Solution
A coaxial resonator system utilizing a conical insert with extended support legs and strategically positioned antennas to separate the TE11 and TEM resonance modes, preventing interference and ensuring accurate salinity measurement by locking the orientation of the TE11 mode and damping the orthogonal mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a coaxial resonator is used to measure conductivity and salinity in multiphase fluid flow, then measurement capability is provided, but degenerate resonance modes (TE11 and TEM) cause interference and reduce measurement precision
Solution Approach 1:
The patent introduces asymmetry by extending one or more support legs of the coaxial insert into the annular volume between the insert and pipe wall. This asymmetric configuration creates different boundary conditions for TE11 and TEM modes, causing their resonance frequencies to separate rather than degenerate. The extended leg acts as an artificial magnetic conductor that selectively affects mode propagation, eliminating the interference that plagues symmetric coaxial resonator designs.
2Measurement precision
If support legs are extended into the annular volume to separate resonance modes, then mode separation and measurement accuracy are improved, but the structural complexity and potential flow interference increase
Solution Approach 1:
The patent segments the support legs of the coaxial insert, extending one or more legs into the annular measurement volume while keeping others shorter or positioned differently. This segmentation approach allows selective interaction with electromagnetic modes without requiring complete redesign of the entire insert structure. The segmented leg configuration provides mode separation functionality with minimal added complexity compared to a fully symmetric design.
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 solution effectively reduces interference from degenerate modes, providing a clear and accurate resonance peak for salinity measurement, enhancing the precision of conductivity and water content analysis in multiphase fluid flows.
Implementation Method 1
the resonant frequency of the first waveguide mode, which in this case is the TE11 mode, will be shifted due to the different boundary conditions in the annular volume
Implementation Method 2
electromagnetic energy can propagate in hollow waveguides (e.g. rectangular or circular waveguides) as wave modes
Implementation Method 3
An artificial magnetic conductor is a surface that behaves like a magnetic wall for magnetic fields, i.e. the tangential component of the magnetic field is zero at the surface
Implementation Method 4
Dissolved salts in the water gives the water conductivity. This may be measured as the salinity will affect the conditions for electromagnetic signals in or close to the microwave range
Data Source
Figure 1
Figure 2a~2b
Figure 2c~2d
AI summary
The present invention relates to a system for measuring electrical characteristics of a fluid flowing through a section of a pipe, the system comprising a coaxial resonator, formed by an essentially coaxial insert in said pipe defining an annular volume between a chosen part of said insert and the pipe wall, said insert and pipe wall being made from an electrically conductive material, the system further comprising at least one antenna adapted to emit electromagnetic signals into and receive electromagnetic signals from said coaxial resonator, and means to measure the frequency response of said coaxial resonator within a frequency range including the waveguide mode TE 11 of said coaxial resonator, The coaxial insert is mounted to the pipe wall through at least one support leg being positioned outside said annular volume, and one electrically conductive fin is positioned at least partially in the annular volume, said fin being positioned in a radial plane, said plane being different from the plane of said at least one antenna and the axis of said annular volume.