SU1511667A1 - Method of acoustic inspection of parameters of media - Google Patents

Abstract

The invention relates to the field of acoustic measurements and can be used to control the physical parameters of media by measuring the propagation velocity and the attenuation coefficient of acoustic oscillations. The purpose of the invention is to improve the accuracy of control and reduce the measurement time. Acoustic oscillations emit into the medium under study and receive them after passing through the medium. The changes in the phase differences of the emitted and received oscillations in standing and traveling waves and the propagation time of the oscillations in the medium are measured, and the increment of the propagation velocity and the absorption coefficient of the acoustic oscillations in the medium are determined according to the calculated formulas. environment. 1 hp ff.

Description

The invention relates to acoustic measurements and can be used to monitor the physical parameters of media by measuring the velocity of propagation and the attenuation coefficient of acoustic oscillations.

The purpose of the invention is to improve the accuracy of control and reduce the measurement time.

The method of acoustic control of media parameters is as follows.

Harmonic acoustic oscillations of the cyclic frequency co emit by the radiator into the medium under study. Acoustic oscillations that pass through the medium are received in the standing-wave mode by the receiver.

The phase difference sr of emitted and received oscillations is described by the expression

SP

Od 9)

/ h sinKL + (KL + & a) + Rsin (KL + i $ g) r2Rsin (KL - S,) -) r cosdCL) Rcos (KL + 5 | + 1 g) - r2Rcos (KL + iJ,)

 where Cfo is a certain constant, independent of the acoustic parameters of the medium;

Rsin (KL + i $ r) r2Rsin (KL - S,)

Rcos (KL + 5 | + 1g) - r2Rcos (KL + iJ,)

K 0/0,

R g G2 top (,) i

3151

C n oi is the propagation velocity and absorption coefficient of acoustic waves in the medium, respectively ;,

L is the distance between the emitter and the oscillation receiver; g epx (i S-f) and

 z

acoustic reflection

waves, respectively, from the radiator and receiver. The change in uqi of the phase difference of the emitted and received oscillations in the standing wave mode is measured. In the case of a small change in the acoustic parameters of the medium, the change in the phase difference is described by the formula

r epxCiS ji) - complex coefficients

(3 (.

i; r

where DC and b oi are the increment of the velocity and the absorption coefficient of acoustic oscillations in the medium, respectively. With a frequency of CO corresponding to

minimum slope frequency-phase

system characteristics emitter receiver,

1 + R

1 - R

a) L with

and in the case of a liquid medium, for which LK 00 (K is a contact) 5

wed 9ci

with

The change in ij of the propagation time of acoustic oscillations in the medium is determined. From the measured values of L 7 and (. P, the increment C and about is determined:

Sig

with ..AG G

1 - R with 1 + R WL

ds).

To determine the increments. From the velocity of propagation of acoustic oscillations, it is possible to additionally receive oscillations passed through the medium in the traveling wave mode and measure the change in them for them. times6674

the phases of the emitted and received oscillations. In this case, the increment of acoustic parameters is determined by the formulas: h

HP OL

H

about ;

. . with

Aoi,

, Bc 1 - rc. ,

(-y COL

Claims (2)

1. The method of acoustic control of medium parameters, which consists in emitting acoustic oscillations into the test medium by means of the radiator, receiving acoustic oscillations transmitted through the medium using a receiver, in a standing-wave mode, the time of propagation of acoustic oscillations is measured in the medium, determine the increment of the propagation velocity and the coefficient of absorption of acoustic oscillations in the medium under study, taking into account the parameters of the medium under investigation, characterized in that, in order to increase the control accuracy and shorten the measurement time, the time increment of distribution d is measured acoustic oscillations in the studied medium and a change in A (-f the phase difference of the emitted and received oscillations, determine the increment li c / absorption coefficient of acoustic oscillations by the formula 40 W 2ciC (AG 2 L1 - R C 1 + R CoL -Atf) where C is the speed of propagation of acoustic oscillations; CO is the cyclic frequency of the emitted oscillations, L is the acoustic base of measurements; R r. (- 2ciL); r, r are the modules of the coefficients of the reflection of acoustic oscillations, respectively, from the radiator and the receiver and on the parameters of the medium under study, judging by the increments D oi of the absorption coefficient and A C of the pacrtpo velocity, the location of the acoustic oscillations. 2. The method according to p. 1, с and с. that additionally 515116676 accept acoustic oscillations, stray acoustic oscillations in  through the medium under study, the medium under study is determined by the forward mode of the traveling wave, the dislocation of the Aifo phases emitted and measured is measured. tic oscillations in the traveling iol – lg mode are usable, and the increment С С is the velocity of propagation