A.N. Grekov, N.A. Grekov, S.S. Peliushenko
Institute of Natural and Technical Systems, RF, Sevastopol, Lenin St., 28
Acoustic flow velocity and direction meters from the IST series are considered. The accuracy of these tools is estimated, which is limited by the effect on the measurement result by the time delays of signals in the transmitting and receiving paths, including delays in acoustic transducers, which significantly depend on temperature and pressure and change with time. An analysis of the flow velocity profile in an acoustic measuring channel, which is inhomogeneous in both laminar and turbulent flow, is presented. The simulation of the flow profile in the measuring tube was carried out and the errors from the oblique jet of the flow were determined in the range of angles from 0° to 30°, which is commensurate with the errors of mechanical vanes. When modeling, the COSMOSFloWorks application of the SolidWorks package was used. As a result of the simulation, the profiles of the flow velocity in the measuring tube were constructed depending on the free flow velocity with a resolution of 1 m/s and a maximum velocity of 5 m/s. The process of measuring the speed of sound and a method for improving the accuracy of the passage of acoustic signals in the measuring channel of the device are considered, taking into account delays. The influence of the flow velocity on the measurement error of the speed of sound is estimated, provided that all time delays of signals in the transmitting and receiving paths, including delays in acoustic transducers, and the change in the length of the measuring base are taken into account. A measurement method has been developed that uses the transit time of repeated acoustic signals reflected from the transducers, which makes it possible to take into account time hardware delays and changes in the length of the measuring base, which affect the determination of the speed of sound and flow.
Keywords: sound speed, flow velocity profile, error, modeling, measurement, acoustic device.
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