SU1472815A1 - Ultrasonic device for determining properties of liquid medium - Google Patents

Abstract

The invention relates to the field of measurements of mechanical quantities and can be used to determine the characteristics of local inhomogeneities, for example, in a stream of liquids. The purpose of the invention is to increase the information content by making it possible to determine the speed of ultrasound in a moving local inhomogeneity of the medium and the speed of its movement. With the help of two pairs of electroacoustic transducers, the acoustic flow of the fluid flow in opposite directions is carried out with acoustic pulses following at intervals much shorter than the ultrasound time of the acoustic base. Using the time interval meter, the times corresponding to the arrival of probe pulses in each of the channels are measured. The required parameters are obtained at the output of the computing unit operating according to the specified algorithm. 2 Il.

Description

1 fc

The invention relates to the measurement of mechanical quantities and can be used to determine the characteristics of local inhomogeneities, for example, in flows of liquids and gases.

The purpose of the invention is to improve the ing formability by making it possible to determine the speed of ultrasound in a moving local inhomogeneity of the medium and its speed of movement.

FIG. 1 shows a block diagram of a device for determining the properties of a moving medium; in fig. 2 is a diagram illustrating the operation of this device.

An ultrasonic device for determining the properties of a moving medium contains four electroacoustic

converter 1-4, generator 5 probe pulses, the output of which is connected to the first 1 and fourth 4 electroacoustic converters, connected to the outputs of the second 2 and third 3, respectively, electroacoustic converters first 6 and in the second 7 amplifiers, meter 8 time intervals, the first input of which connected to the output of the generator 5 probe pulses, and the second and third inputs are connected respectively to the outputs of the first 6 and second 7 amplifiers, block 9 calculating return values, the first 10 and second 11 adders Block 12 for calculating the required parameters, the third 13 and fourth adders 14, the first 15 and second comparing circuit 16, an AND gate

Ј

BE

00

ate

314

And 17, a counter 18 and a memory unit 19, wherein the output of the meter 8 time slots is connected to the inputs of the block 9 for calculating return values, the first 10 and second 11 adders and the first input of block 12 for calculating the desired parameters, the output of block 9 for calculating the return values is connected to the inputs of the third 13 and fourth 14 summers, the outputs of which are connected respectively to the third and fourth inputs of the unit 12 for calculating the desired parameters, the outputs of the first 10 and second 11 summers are connected respectively to the first inputs of the first 15 and second 16 blocks comparison, the second inputs of which are connected respectively to the first and second outputs of the memory block 19, the third output of which is connected to the second input of the block 12 for calculating the desired parameters, the fifth input of the latter is connected to the output of the counter 18, the control input is connected to the output of the logic element I 17, and the control output to the first input of the counter 18 and the control input of the generator 5 probe pulses, and the second input of the counter 18 is connected to the second output of the generator 5 probe pulses.

The device works as follows.

In the studied medium, the speed of which is v6 and the speed of ultrasound in which is c0, at time points

{t (} to ti - t; - t «l (1)

electro-acoustic transducers 1 and 4 emit probe pulses in two opposite directions. The filling wavelength of the ultrasonic pulse is set much shorter than the base distance 1, and the period of sounding is determined by the condition

Ј (t) 4l -t), (2)

where mmi is the minimum delay time of the probe pulses in the medium as they pass the base distance. Electroacoustic transducers of 1.3 and 2%, 4 are installed at distances from one another, many shorter distances 1.

The past distance 1 in the medium probing pulses are taken by electroacoustic transducers 2 and 3 into a priori unknown

154

time cops {tl | l and | v; (figure 2),

G (+ h where t; I - the time of admission

probe signals emitted in the direction of the velocity vector V;

IVm 1

t; J - the same, in the opposite direction. According to the moments of time ftL of radiation and the time of reception of the GM1 DG-) 1

tj J, | t; J SENSING PULSES

The time interval meter 8 determines their digital values Gt ;,

. KP First adder 10 determines the value of the time interval according to the expression

h ", (+ l

 I 1st

(3)

and the second adder 11 - the value of the time interval according to the expression

(four)

I

(- tn t; + i T

Schemes 15 and 16 of the comparison compare the value of H (t with the value of R 4, and the value of Ј 1G with the value according to the expressions

 ; (5) lf.,. (6)

where Ј is the value of g,

The values of M4 and Rf are recorded in memory block 19. The kx values are set in accordance with the statement of the measurement problem, for example, by the expressions:

IA

i

C0 + v0 c0 + v0 + (& c + bv + Sc + Sv)

(7)

R4 -i- + ij

 cc-iv0- (uc + Јv + 8c + fiv)

(eight)

where & c is the detection threshold for local inhomogeneity of the ultrasound velocity in the medium; uv is the threshold for detecting the rate of movement of local inhomogeneity in the medium;

a s is the permissible error of measuring the velocity of ultrasound in the medium;

S v -. The error of measuring the velocity of the medium is permissible.

BUT

Values with + vc

ft 4

 о С0 vo values of v0 are set a priori or with the involvement of measuring information about the parameters of the medium under study. The sign of the detection thresholds is established depending on the physical nature of the local heterogeneity and the medium (gas, liquid, etc.).

In case of fulfillment of conditions (5) and (6) the decision on the presence of local heterogeneity is not taken, at the output of the logical element AND 17 there is a logical zero. The adders 14 and 13 and the block 9 for calculating the inverse values determine the ultrasound velocity estimates in

H

-0;) TG +1;

(14)

(c0; -v0;) t (rij :(. Llli

+ i

2cc (15).

, (+ l

HA

: kiri iJTli ±. (ioiAvoiJJrlpiA dJZL

2co | (+

+ () t G;

(sixteen)

/ .Л «Ј, т. {+

: iЈaLzY2JlliI ± iЈfl ± YoLiiIJdL +

-(with.

2c

H; .,

. "4 g

(17)

x

1 Ј: x | 0 1 | Y ± X ° a1tЈ14

and the velocity of the medium V0;

This;

according to the expressions:

l

And x

s °; (

L

. (-

01 2, and,

+1);

iV

i- tt

(9)

-t

-).

(YU)

TV1 -T; TV-T; In the case when conditions (5) and (6)

for i-x j j and are not executed, the blocks 15-17 make a decision about the presence of local heterogeneity and the AND 17 gate outputs a logical unit to the control input of the block 12 for calculating the desired parameters. At this command, in block 12, from the outputs of adders 14 and 13 are entered

A l

C0 estimates; and v0; , from the output of memory block 19, the value of the value, from the output of the counter 18, the value of i, from the output of the meter 8 time intervals, the digital values Gt. T,;

hCG

Block 12 for calculating the desired parameters determines the coordinates of points B, D, D, E (Fig. 2) using an algorithm that implements the expressions:

, (., J

t elЈuLIX5i.lli-j ± ЈAL ± Y5Llii. (N) in l

2c0;

 BUT . And .W. useful for: i: ° L-J J: i; i iiЈsi ty iJJ-S physical objects and 2cc; properties, for example, pr;

A a

 (with „; -vo;

 TD 1; (12)

t, Јо) (Ј..ГГаат1 1 +1.

2C; (13)

"(C,

2t

45 fio compared with the standing pulse pulse.

Use of images is useful for detecting

during the formation of bubbles, initial fluid supply in

55 installations, etc ..

Claims (1)

Formula isob Ultrasonic device motion properties 2s Kc + v) (- voi / x (18) Using the obtained coordinate values (11) - (18), block 12 calculates the ultrasound velocity estimates from Heterogeneity and velocity of the linac in its local engine, + fl2te); (19) i Cd-tetr-CE L V. 1 / -5 & I 1 2х15Ј- iVj. “, 24A-t tr-te (20) . useful for: physical objects and properties, for example, pr; Thus, an increase in the information content is achieved by making it possible to determine the speed of movement of a local inhomogeneity. 5 and the ultrasound velocity in it, when the local inhomogeneity is characterized by the differing ultrasound velocity from the ultrasound velocity in the medium and the differing speed of movement from Q velocity of the medium, as well as linear dimensions, smaller in comparison with the base distance, and residence time in the core of the measuring transducer, smaller 5 fio compared with the transit time of the baseline probe pulse. The use of the invention is most useful for detecting local determining them in the study of the formation of cavitation bubbles, the initial phases of the boiling coolants in the energy 5 installations etc .. Invention Formula An ultrasonic device for determining the properties of a moving medium, containing four electroacoustic transducers, a probe pulse generator, the output of which is connected to the first and fourth electroacoustic converters, connected to the outputs of the second and third electroacoustic transducers, first and second amplifiers, time meter, the first input of which is connected to the output of the probe pulse generator, and the second and third inputs are connected respectively to the output The first and second amplifiers, the inverse value calculation unit, the first and second adders and the required parameters calculation unit, are characterized in that, in order to increase the information content by determining the ultrasound velocity in the moving local inhomogeneity of the medium and the velocity of its movement -T; No, it is equipped with the third and fourth adders, the first and second comparison circuits, the AND logic unit, the counter and the memory unit, the output of the time interval meter is connected to the inputs of the reciprocal calculation unit, the first and second adders and the first input of the required parameters calculation unit, output the block for calculating the return values is connected to the inputs of the third and fourth adders, the outputs of which are connected respectively to the third and 0 to the fourth inputs of the unit for calculating the desired parameters, the outputs of the first and second adders are connected respectively to the Perz inputs of the first and second comparison blocks, the second inputs 5 of which are connected respectively to the first and second outputs of the memory block, the third output of which is connected to the second input of the block for calculating the desired parameters, the fifth input of the last Q is connected to the output of the counter, the control input is connected to the output of the logic element I, and the control output - to the first input of the counter and to the control input of the zone generator 5 of the Driving pulses, and the second input of the counter connected to the second output of the generator of the probing pulses. Fig i ti ti  J.W  + ( .f ti FIG. 2 tf} t (ll tt. Zt- + 1 / J.W + ( ti + {+) j. t