METHOD FOR ACOUSTIC MEASUREMENT OF SOUND VELOCITY AND FLOW OF LIQUID OR GAS WHEN AMBIENT TEMPERATURE CHANGES Russian patent published in 2023 - IPC G01F1/66 G01P5/24 

FIELD: measurement technology.

SUBSTANCE: with the claimed method, elastic waves are excited in the form of an impulse along the flow and against the flow at different angles to the flow axis. The time taken by the pulses to pass the base distance from the transmitter to the receiver is measured in two directions: along and against the flow. The values of the flow velocity are calculated using the difference in the times of these pulses travel through the base distance. The time of passage of repeated acoustic signals reflected from the transducers is pre-measured in distilled water, in addition to the above parameters. Based on the totality of the measured data, the calculation excludes the time delays of the signals that appear in the electro-acoustic path of the receiving-emitting piezoelectric transducers and electronic circuits. The length of the measuring base for a specific temperature is determined. Using the obtained value of the length of the measuring base on temperature, the speed of sound in liquid media with different densities and temperatures is determined by the formula:

where V is the flow rate of the liquid medium; C(T) is the speed of sound in a liquid medium at a specific temperature T; L(T)-C_∂ (T)Δτ_∂, L(T) is the length of the measuring base at a specific temperature T, determined in distilled water, at V=0, Δτ is the difference between the sum of the times of passage of pulses of repeated acoustic signals reflected from the transducers and the sum of the times of passage of the base distance in two directions along and against the flow in a liquid medium, Δτ_∂ is the same for distilled water.

EFFECT: increase in the accuracy of measuring the speed of sound in a liquid medium flow with simultaneous temperature measurement.

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