Ultrasonic Flow Meter Using Lamb-Wave Multipath Measurement
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Solution Overview
Problem
Conventional ultrasonic transit-time flow measurement techniques face challenges in accuracy due to uncertainties related to temperature, pressure, and fluid composition, especially in complex multiphase mixtures, requiring additional complex and costly measurements for sound velocity determination.
Innovation Solution
A flow measuring apparatus utilizing Lamb-wave ultrasonic radiation that couples directly through conduit walls to measure flow velocity and sound velocity, decoupling the transducer distance from the angle of radiation, allowing for accurate measurements independent of flow velocity and reducing uncertainties in propagation paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ultrasonic transit-time flow measurement is used with fixed acoustic propagation path, then flow velocity can be measured, but measurement accuracy deteriorates due to uncertainties in temperature, pressure, and fluid composition
Solution Approach 1:
The patent changes the measurement parameters by using multiple ultrasonic paths with different orientations (at least two different angles relative to the conduit axis). This allows the system to measure both flow velocity and sound velocity simultaneously, compensating for temperature, pressure, and composition variations through mathematical processing of the multiple path measurements.
Solution Approach 2:
The ultrasonic measurement system is designed to perform multiple functions: measuring flow velocity, sound velocity, temperature, and pressure simultaneously using the same transducer array and processing system. This multi-functionality eliminates the need for separate measurement devices and provides comprehensive fluid characterization.
2Measurement precision
If additional measurements are added to determine sound velocity in complex multiphase mixtures, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The same ultrasonic transducer array and signal processing system used for flow velocity measurement are also used to determine sound velocity, temperature, and pressure. By analyzing the transit times across multiple paths with different orientations, the system extracts multiple fluid properties simultaneously without adding separate measurement devices.
Solution Approach 2:
The system uses changes in ultrasonic transit time across multiple paths to derive sound velocity and other fluid properties. By processing the differential transit times from paths at different angles, the system can calculate sound velocity in the fluid even in complex multiphase mixtures where traditional methods fail.
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 apparatus provides robust and accurate measurements of flow velocity and sound velocity without the need for critical transducer spacing, reducing measurement uncertainties and complexity, and enabling reliable fluid characterization in multiphase flows.
Implementation Method 1
a first path solely via the one or more walls for Lamb-wave ultrasonic radiation coupling directly from at least one transducer emitting ultrasonic radiation to at least one transducer receiving ultrasonic radiation
Implementation Method 2
Lamb-wave ultrasonic radiation coupling directly from at least one transducer emitting ultrasonic radiation to at least one transducer receiving ultrasonic radiation
Data Source
AI summary
A flow measuring apparatus measures a fluid flow within a conduit including a wall. The apparatus includes a transducer arrangement including at least two transducers for alternately emitting and receiving ultrasonic radiation through the conduit wall and the flow. The apparatus also includes a signal processing arrangement for generating signals to excite the transducer arrangement and for processing received signals provided by the transducer arrangement for generating output signals from the signal processing arrangement indicative of properties of the flow. The transducer arrangement in cooperation with the conduit provides a first path for Lamb-wave ultrasonic radiation coupling directly from a first of the at least two transducers, to a second of said at least two transducers to generate a first received signal. The transducer arrangement in cooperation with the conduit provides at least one second path for ultrasonic propagation along the wall via Lamb waves coupling to at least a portion of the flow from a first of the at least two transducers to a second of the at least two transducers to generate a second received signal. The signal processing arrangement determines from said first and second received signals ultrasonic radiation propagation time periods through the first path and through the at least one second path, and to perform computational operations on the propagation time periods to determine properties of the flow including, but not limited to, at least one of: fluid flow velocity (v) in the conduit, a sound velocity (c) through the fluid.