Flow acoustics modelling and implications for ultrasonic flow measurement based on the transit-time method.
A comparison between three mathematical models frequently used in flow acoustics is presented and discussed with respect to ultrasonic flow-meter performance based on the transit-time method. The flow-meter spoolpiece geometry is assumed to be a cylindrical pipe. Semi-analytical calculations employing the Frobenius power series expansion method are shown for the cases of a constant-, linear-, parabolic-, and cubic-flow profiles although the Frobenius method presented can be applied to any smooth flow profile. It is shown that the so-called deviation of measurement, often used as a measure of the flow-meter accuracy, is strongly dependent on the acoustic mode excited and the flow profile. Furthermore, differences with respect to deviation of measurement results exist among the three mathematical models analyzed.
Willatzen
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Mads Clausen Institute for Product Innovation, University of Southern Denmark, Grundtvigs Alle 150, DK-6400 Sønderborg, Denmark. willatzen@mci.sdu.dk