A novel mathematical model for transit-time ultrasonic flow measurement

Lei Kang, Andrew Feeney, Will Somerset, Riliang Su, David Lines, Sivaram Nishal Ramadas, Steve Dixon

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    The calculation of the averaged flow velocity along an ultrasonic path is the core step in ultrasonic transit-time flow measurement. The conventional model for calculating the path-averaged velocity does not consider the influence of the flow velocity on the propagation direction of the ultrasonic wave and can introduce error when the sound speed is not much greater than the flow velocity. To solve this problem, a new mathematical model covering the influence of the flow velocity is proposed. It has been found that the same mathematical expressions of the path-averaged flow velocity, as a function of the absolute time-of-flight (ToFs) of ultrasonic waves travelling upstream and downstream, can be derived based on either of the models. However, the expressions as a function of the time difference (the relative ToF) between the ultrasonic waves travelling upstream and downstream derived by the two models are completely different. Flow tests are conducted in a calibrated flow rig utilising air as flowing medium. Experimental results demonstrate that the path-averaged flow velocities, calculated using either the relative or the absolute ToFs based on the new model, are much more consistent and stable, whereas those calculated based on the conventional model have shown evident and increasing discrepancy when the flow velocity exceeds 15 m/s. When the flow velocity is around 39.45 m/s, the discrepancy is as high as 0.38 m/s. As the relative ToF can be more accurately, reliably and conveniently measured in real applications, the proposed mathematical model has a great potential for the increase of the accuracy of the ultrasonic transit-time flowmeters, especially for the applications such as the measurement of fluids with high flow velocities.

    Original languageEnglish
    Title of host publication2019 IEEE International Ultrasonics Symposium, IUS 2019
    PublisherIEEE Computer Society
    Pages1590-1593
    Number of pages4
    ISBN (Electronic)9781728145969
    ISBN (Print)9781728145976
    DOIs
    Publication statusPublished - 8 Dec 2019
    Event2019 IEEE International Ultrasonics Symposium, IUS 2019 - Glasgow, United Kingdom
    Duration: 6 Oct 20199 Oct 2019

    Publication series

    NameIEEE International Ultrasonics Symposium, IUS
    ISSN (Print)1948-5719
    ISSN (Electronic)1948-5727

    Conference

    Conference2019 IEEE International Ultrasonics Symposium, IUS 2019
    Country/TerritoryUnited Kingdom
    CityGlasgow
    Period6/10/199/10/19

    Keywords

    • mathematical model
    • time-of-flight
    • ultrasonic flowmeter
    • ultrasonic transducer
    • ultrasonic transit-time flow measurement

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