Density patterns of the inhomogeneous liquids in the industrial pipe-lines measured by means of radiometric scanning

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LA HOUILLE BLANCHE / N° 1 - 1973

Density patterns of the inhomogeneous liquids in the industrial pipe-Hnes

measured by means of radiometric scanning :;:

by Miss A. Michalik

Institute of Nuelear Techniques

Academy of Mining and Metallurgy, Krakow, Poil and

Introduction

Radiometrie methods were found to be most useful in measurements of the flow parameters of the unhomoge- neous hydromixtures [1]. The radiometric method for determining a spatial distribution of concentration was developed a few years ago. This method is based on the recording of the changes in radiation intensity of the gamma-ray beam continuously penetrating a pipe-line cross- section [2]. The scanning device applied for this purpose is a special type of density meter which enables the determination of the density of the flowing medium at any point of its cross-section. The scanning head is applicable to the industrial pipe-lines of D_p = (200-220) mm.

This paper deals with a preliminary analysis of the results of measurements carried out at the" Sosnowiec" coal-mine stowing installation.

Experimental procedure

The hydrotransport installation at the" Sosnowiec" coal- mine is used to convey the stowing mixture, which consists of sand and water and is used to fill up worked-out cavities.

A simplified diagram of this installation is shown in Figure 1. From the in-flow filling funnel the stowing mixture flows alonga vertical pipe-line (122 m length) and a horizontal pipe-line (1,620 m length) to the worked-out cavity. A radioistotope density meter placed just under the pipe-line inlet, enables a continuous measurement of the mean density of the flowing mixture [3]. The scanning

(*) The work was do ne within the framework of LA.E.A. Research contract n" 1175/RB.

53

device was placed on the horizontal pipe-line section at the distance of 700 m from the shaft. The flow of the measured mixture is enforced by the gravitation, which causes a regulation of the mean flow velocity impossible. The mean flow velocity was measured independently [4]. Its values varied in a range between 3.85 mis and 4.25 rn/s, depending on the actual mean density of the mixture. It was thus assumed on the basis of these measurements that

v

^{= 4.00}^± ^{10% rn/s.} ^The ^mixture ^under investigation consists of sand (y=2.65 g/cm3 ) and water (y=1.00 g/cm3 ).

The granulome tric composition of sand is shown in Figure 2. In the measurements the only changing parameter was the mean density of mixture continuously controlled

1/

Simplificd scheme of industriaI installation.

1: inlet of pipe-line; 3: measuring hcad of radioisotope gauge;

4 and 5: eleetronic assembly of the radioisotope densimeter;

6: head of radiometrie scanning device; 7: clectronic assembly of racliometric scanning device.

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%

0.1 0.2 03 0.4 0.5 0.6 Cv

o.i 02 03 0.4 05 06 ^Cv

1.0 09 OB 0.2 0.1 10 -

09 OB 07 0.6 05 0.4

yID

1]=y/D, c

=

~m-p",

"

p"-p,,,

where:

b/.Cv~ 0.24, v ~4.00±10%

3/

Distributions and promes of volumetrie concentration in researched cross·section of pipe:

a) for mean concentration ëv

=

^0,15;

b) for mean concentration ëv

=

^0,24.

Pm is the mean, "in·line" density of mixture; p", p", are the densities of sand and water respectively, y is the vertical distance from the bottom, D is the internal pipe diameter.

The obtained results are also interpreted by means of the relation c,,(ê

v ⁼

^f^(1]), ^where

Cv

is the mean volumetrie concentration in the investigated cross-section. This form of presentation of the results is more precise than that:

c,,/

c"o

=

f(1]), usually applied by many authors [6 and 7], where c" is related to the chosen value of concentration c"o, e.g. _{CO.0 5 •} The above relation is presented in Figure 7

in form

cvlc

v versus 1].

The accuracy of the measurements performed has been estimated at a level of the rela~ive error equal ta 5%.

Independently, measurement resuJts have been checked as far as their reliability is concerned by comparing concen-

d/mm/

5.0 2.0 3.0

0.5 1.0 0.2 0.3

2/

Grain composition of applied sand.

I----+--+--j[.\\-f--H-+-l--l----+---+--+-f--f--l--++-I50

l---t---+--+-tⁱ\t--+++++----t---+---+-+-+++-H40

I----+--+-+-+-++-I-+-I---+--+--+--+-++-I-I-I 60 The direct results of the measurement are obtained as the records of gamma radiation intensity from the scanning of the mixture stream cross-section. About 100 records were obtained altogether for various mean sand concentrations. They enable the calculations of density diagrams on the basis of the theoretical approach presented in the paper [5]. The final results of the computer calculations have the form of maps of local density distributions in the mixture stream cross-section (an example: density diagram nO 1).

In Figures 3, 4, 5 and Figure 6 eight local concentration distributions of sand for some chosen mean densities were exemplified. They are the transformations of local density distributions obtained from computer calculations. Also a volumetrie concentration profile along the vertical diameter of the cross-section was shown for each case. Such a profile can be described as follows:

c"

=

f(l))

time in which the fiow conditions are sufficiently constant.

In practice, it was possible to keep constant fiow conditions for the period of several scanning runs. e.g. the spatial distribution of concentration was measured 30 times for density

p

= 1.3g/cm:\ 15 times for

p

= 1.5 g/cm:^J and 4 times for

p

⁼ ^{1.9 g/cm:}^{J •}

Results of measurements

t---+---+-+--+-+t l

\-i-H-+----+--+-+--+-++-I-+-J¹⁰

i....

t----t---f-+--Ift-IH+++---+--+--+-I-I-l--J--.--i-i³⁰

l---+---+--+--l--\+--I \

++-I---+---I--+--+-H-++-I20

I--~"'~-t-+-+-+++-++----I--t-+-+-++H~

⁹⁰

. \ !

1----+--4\-+-+--1-¹-+-1-++---l----l---1-I-If--l---l--1-I 80

1\

¹

l---+-~++--I-I\-+--~_+_I__+_J_!_____l__.I.70

0.1

54

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al. Cv =0.27, v=4.00±10°,(,

09 OB 07 06

05 04 0.3 02 01

01 0203 04 05 06 Cy

A. MICHALIK

al. Cv 0.42, v = 4.00 ± 100;0 y/a 10 09 0.8 07 06

0.5 04 03 02 01

0.1 02 03 04 05 0.6 07Cy

b/. Cv = 0.31, v= 4.00±10°10

0.9 OB Cl7 06 05 04 03 02 01

b/. Cy = 0.45, v= 4.00± 10°,(, yID

0.9 0.8 07 06 05 0.4

03 0.2 0.1

0.1 02 0.3 0.4 05 06 07 cy 0.1 02 030.4 0.5 C_y

4/

Distributions and profiles of volumetrie concentration in the researched cross-section of pipe:

a) for mean concentration Cv

=

^0,27;

b) for mean concentration Cv

=

^0,31.

tration profiles obtained in the identical f10w conditions.

Figure 8 shows three concentration profiles obtained from six measurements of concentration distribution for mean density p

=

1.30g/ cma. The analysis proves that the error of the results of several distribution measurements does not exceecl 5%.

Discussion

On the ground of the obtained concentration distributions an analysis was carried out. It was made to check well-known theories dealing with a concentration distribution [6]. First of ail, Makkaveev diffusion theory [6] and Veli- kanov gravitational theory [7] were taken into considera- tion. These theories mainly apply to very low concentrations of solid phase, although there were some suggestions applying them to the concentration distributions for higher concentrations[8]. According to both theories the concen-

5/

Distributions and profiles of volumetrie concentration in the researched cross-section of pipe:

a) for mean concentration

c" =

0,42;

b) for mean concentrationCv

=

^0,45.

tration profile should have an exponential character. On the ground of the carried-out investigations a high discre- pancy between the theoretical and experimental curves have been observed. Even for the mean volumetric concentration ^Cv

=

0.06 the concentration profile is not exponential one (Fig. 7).

Pechenkin's theory [8] seems to be much doser to the obtained results but in a small range of the mean concentrations from ^Cv

=

0.06 to Cv

=

0.17. While comparing the theories with the experimental data a certain apprcxi- mation was adopted since in many cases it was impossible to find any data corresponding to the conditions of the measured f1ow. The concentration profiles presented in Figure 7 deal with the range of highly concentrated mixtures.

For "CI)

=

0.15 and "Cv

=

0.19 the profiles have a similar shape and are included in a local concentration interval from c_v

=

0 to Cv

=

0040. Similar results in this concentration region were obtained by Ayukava [9]. However the present results are not in agreement with the results of

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6/

Distributions and profiles of volumetric researched cross-section of pipe:

(1) for mean concentration'Cv

=

^0,48;

b) for mcan conccntration 'Cv

=

^0,54.

Acknowledgements

The author is greatly indepted to Mr. K. Korbel and Mr. K. Przewlocki for their valuable remarks and discus- sions during preparing this paper for publication. The participation of the scientific and technical staff of the Laboratory of Nuclear Instruments at the Institute of Nuc1ear Techniques in Cracow, and especially of Mr. L.

Kalemba in perfoming the radiometric in-field measurements is also gratefully acknowledged.

bution with a graduaI shift of the concentration maximum towards the top.

In the case of concentration

Cv

= 0.25 the concentration maximum is at the relative distance YI = 0.15 from the bottom. At greater mean concentrations a further shift of the maximum is observed: for the concentration

Cv =

0.48 from the distance 11

=

0.20 to 11

=

0.30. For

Cv

= 0.54 the greatest concentration occurs at the relative height 11

=

^{0.30 to 11}

=

^0.45.

In this range of mean concentrations a distinct flattening of the distribution of solid phase concentrations is observed.

The presented measurements are only a preliminary part of much wider research programme, since they were carried·

out in a very small velocity range.

The developed programme includes measurements at several mean velocities -in the superterminal velocity range for mixtures of various mean densities. Since it is impossible to regulate the fIow in industrial installations, the research will be continued at the hydraulic laboratory.

concentration in the Of 0.2 0.3 04 05 06 D.7Cv

0.1 02 0.3 04 0.5 06 0.7 Cv

0.2 0.1 y/0

la

09 - OB 0.7 0.6 0.5

0.4 D3 10 Dg OB

0.7 0.6

05 DA

0.3 0.2 01

7/ The family of curves cvlëv

=

f(YID):

1: forëv

=

0,18; 2: for'Cv

=

0,24; 3: forë"

=

0,30;

4: for'Cv

=

·0,42; 5 : for'Cv

=

0,48; 6 : forëv

=

^0,54.

0.4 0·5 v= 4 00±10%

. 1,2,3 - Cv:=0.20

0.2 0.1

0.1

8/

Three profiles of volumetric concentrationëv

=

0,20 (obtained in six measurement runs).

0.2 0.5.

o.

0.6 0.7

OA y/a

v:::4.001 10%

1 - Cv "" 0.18 2-Cv ""0.24 3-c_v""ü3ü 4_~Cv ""042 5-ê_v""OA8 6 - Cv=0.54 5 6

0.5 C 7

0.8.

0.6

0.4

0.3.

0.2 0.1 y/a 1.0·

56

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A. MICHALIK

1.22 1.26 1.30 1.33 1.36 1,'0 1.41 1.43 1044 1.45 1.45 1.45 1.44 1.43 1.42 1.40 1.38 1.15 1,32

?oc.i·= 17/13 - 69 r.

1.0

.9 .8

.2

1.09 1.09 1.08 1.06 1.05 1.13 1.14 1.1 J 1.14 1.13 1.12 1.11 1.10 1.10 1.14 1.15 1.17 1;18 1.17 1.18 1,18 1.17 1.17 1.16 1.;1 5 1.14 1.14 1.15 1.18 1.18 1.20 1.21 1.2J 1.23 1.24 1.24 1.23 1.2< ·1.22 1.21 1.20 1.17 1.19 1.22 1.24 1.26 1.26 1.28 1.27 1,30 1.30 1.30 1.29 1.26 1.27 1.26 1,24 1.20 1.23 1.27 1.23 l,J1 1.33 1.34 1.35 1.36 1.37 1,35 1.35 1.33 1.32 1,30 1.23 1.27 1.22 1.25 1,29 1,32 1.34 1.36 1.37 1,39 1.39 1.39 1.39 1,3E 1,37 1.36 1.34 1,32 1,30

.1

.0 -.1 -.2

-.5 -.6

-.7 -.8 -.9 -.10

1.26 1.30 1.35 1.38 1.41 1.44 1.46 1.49 1,50 1,51 1,51 1,51 1.50 1.49 1.47 1.45 1.43 1.39 1.36

1.34 1.33 1.43 1.46 1,50 1.53 1.57 1.59 1,59 \61 1,61 1.50 1.59 1,57 1,56 1,55 1.51 1.47 1.43 1.37 1.';2 1.02 l,tE 1.50 1,54 1,57 \é" 1.5: 1.6:. 1.65 1.66 1.5é 1.6J 1,51 1,59 1,55 1.51 1,46

-1.8 -.~ -.c - . , -.S - .0 .1 . ) • .'.i. .5 . 0 1.0

References

[1] PRZEWLOCKI (K). - Investigations of the fluidized solids by radiometrie methods in colliery stowing pipe-line. Scientifie Bulletins nO 119,Academy of Mining and Metallurgy, Craeow (1965).

[2] MICHALIK (A), PRZEWLOCKI (K), PRAXMAYER (T.). - A Radio- metrie method of determination of the spatial distribution of density in closed media. Nukleonika l, Warsaw (1968).

[3] KORBEL (K). - The Applicability of the radiogauges for measuring the density of the flow solids-liquids mixtures. Isoto- penpraxis, 6 Jahrgang, Heft 7 (1970).

[4] KORBEL (K.), KRASOWSKI (R.), MICHALIK (A), NIZEGORODCEW (P.), PRZEWLOCKI (K). - Determination of sorne kinematie charaeteristics of flow of stowing slurry by means of radiometric measuring methods. Nukleonika, XV, nO 3 (1970), 291.

[5] KORBEL (K.), MICHALIK (A), NIZEGORODCEW (P.), PRZEWLOCKI (K). - Final report for International Atomic Energy Ageney, aecording to the Research Agreement 465/CF, Cracow (1970).

[6] MICHAJLOVA (N.A). - Pierenos tviordych castie turbulentnymi potokami vody. Gidrotiechn. Izdat, Leningrad (1966).

[7] VELIKANOV (M.A). - Dinamika ruslovych potokov. Gosu- darsty. Izdat. Tiechn. Tieoret. Litieratury, Moseow (1954).

[8] PECHENKIN (M. V.). - Experimental studies of flow with high solid particle concentrations. Proc. of the XIII Congr.

I.A.H.R., 2 (1969), Japan, 157-164.

[9] AYUKAVA (K). - Veloeity distribution and pressure drop of heterogeneousty suspended flow in hydraulic transport through a horizontal pipe. I Int. Conf. Hydr. Transp. in Pipes (1970), F3.

[10] SILIN (N.A), PICHTCHENKO (1.A), OCHERETKO (V. F.). - Eksperimentalnoje issliedovanije raspriedie!enije osriedniennych skorostiej, konsistiencij i krupnosti castie po sjeceniju trubo- provoda pri dvizeni dvuehkomponentnyeh potokov.Izdatielstvo, An. S.S.S.R., Kiev, 1964.