Non-Invasive Open-Channel Flow Meter Using Microwave Velocity Profiling
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Solution Overview
Problem
Existing non-invasive flow measurement technologies for open channels suffer from inaccuracies due to the use of wetted sensors that are prone to debris accumulation, complexity in installation, and assumptions of symmetrical velocity distributions, leading to errors in flow calculations.
Innovation Solution
A non-invasive method using a microwave beam directed towards the fluid surface, with phase shift analysis of reflected signals to calculate the azimuth angles and elevation angles, allowing for precise determination of the fluid flow surface velocity profile without direct contact with the fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wetted sensors are placed at or near the bottom of the pipe or channel to measure velocity, then velocity measurement is achieved, but the sensors are exposed to debris and hang-ups causing inaccuracies or malfunctions
Solution Approach 1:
The patent introduces an intermediary medium (electromagnetic or acoustic waves) to transfer velocity measurement information from the fluid to the sensor without direct physical contact. The sensor measures velocity by detecting Doppler shifts or other wave-fluid interactions through the fluid medium, keeping the sensor isolated from debris while maintaining measurement capability.
Solution Approach 2:
The patent replaces mechanical wetted sensors with non-contact electromagnetic or acoustic measurement systems. Instead of physical sensors touching the fluid, the system uses wave-based measurement techniques (such as Doppler radar or acoustic Doppler) to measure fluid velocity remotely, eliminating mechanical wear and debris accumulation issues.
2Ease of operation
If non-invasive flowmeters use surface velocity measurement with mathematical models to calculate average velocity, then installation complexity is reduced, but large inaccuracies occur due to deviations from average velocity
Solution Approach 1:
The patent divides the measurement approach into multiple discrete velocity measurements taken at different locations or angles across the flow profile. By segmenting the measurement space and combining multiple measurements, the system captures the true velocity distribution without requiring complex mathematical modeling assumptions, thereby improving accuracy while maintaining ease of installation.
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
Provides accurate and reliable flow measurements by determining the complete fluid flow surface velocity profile and distance from the microwave system using a single antenna, reducing errors associated with previous methods.
Implementation Method 1
A non-invasive method using a microwave beam directed towards the fluid surface, with phase shift analysis of reflected signals to calculate the azimuth angles and elevation angles, allowing for precise determination of the fluid flow surface velocity profile
Implementation Method 2
phase shift analysis of reflected signals to calculate the azimuth angles and elevation angles, allowing for precise determination of the fluid flow surface velocity profile
Data Source
AI summary
A method measures surface velocity of a fluid having a free surface flowing through a pipe or a channel. A microwave beam is sent by patch antenna including an emitting patch area and receiving patch areas parallel to the emitting patch area. Microwave signals reflected by the moving fluid free surface are received on the receiving patch areas separated by a predetermined distance. The patch antennae are either in horizontal or vertical planes parallel to the average fluid velocity. For each microwave signal received, a phase shift between microwave signals received by different patch areas is determined to calculate azimuth angles and azimuth position of reflectors on the fluid surface or to calculate the elevation angle corresponding to each signal received. Based on Doppler frequency shifts between the sent and received microwaves and corresponding phase shifts, lateral and/or longitudinal distribution of the surface velocity of the fluid is calculated.