ML20064N358
| ML20064N358 | |
| Person / Time | |
|---|---|
| Site: | Neely Research Reactor, 05000276 |
| Issue date: | 03/31/1994 |
| From: | Weatherhead R ARGONNE NATIONAL LABORATORY |
| To: | |
| Shared Package | |
| ML20064N355 | List: |
| References | |
| ANL-6675, NUDOCS 9403290276 | |
| Download: ML20064N358 (6) | |
Text
.
-\
ANL-6675 Engineering and Equipment (TID-4500,19th Ed.) .i AEC Research and Development Report i ARGONNE NATIONAL LABORATORY 9700 South Cass Avenue Argonne, Illinois NUCLEATE BOILING CHARACTERISTICS AND THE CRITICAL s HEAT FLUX OCCURRENCE IN SUBCOOLED '
AXIAL-FLOW WATER SYSTEMS by R. J. Weatherhead Reactor Engineering Division h
a l'.
1 March 1963 I
- f L_ Ope rated by The University of Chicago 3 under J. Cont ract W-31 -109-eng-38 l; with the U. S. Atomic Energy Commission u
9403290276 940321 g PDR ADOCK 05000160 b p PDR p
7 JW 18 ' -
SfI w 4 basis of a stratified bubble flow, the separative action of the flow-stream-velocity profile tending to segregate the bubbics in a sub-boundary laye r adjacent to the zone of interfacial turbulence. With the degree of segrega-tion inc reasing directly with mass velocity, the sub-boundary bubble layer inc reasingly absorbs the mixing action of the nucleation turbulence, with resulting decreases in the heat transfer, critical het t flux, and flow friction.
Gunthe r,(ll) whose low pressure, critical heat flux data show a steep dependency on linear subcooling similar to that m Fig.10, reports visual observation of bubble segregation on or near the tra.nsfer surface at high local subcoolings, the bubbles traveling at approximately 80% of the flow stream velocity. Figure 16 shows a correlation of these data in a form similar to that of Eq. (7), the differing flow regimes requiring changes ,
in the coefficient, mass velocity, and subcooling te rms; 6 H[ - H \
Q"/10 =
1.75 D-u 2 (Hfg /10 )(1 + G/10 6)v 2 3 '
(g)
N With the equivalent diameter evaluated on the basis of the boiling surface if only, the validity of the latent heat and equivalent-diameter terms is illus- Q, trated by the comparison with the ANL and BMI data from small tubes at 200 and 2000 psia. The mass -velocity term was empirically determined, and its proportional difference from Gunther's original velocity term is g@
?
generally small; the linear approximation of the subcooling is retained 7.:
from the original. {f;(
@A 30 "
i i i i I i i_
i 6 i,Ig e !
-- pq VERTICAL CHA4'l(L (REF. li)
MEATto D = 1,5 in.
h
$#4 (4-164 osia , p. fl G G n 108 is/ist) (st23 9 - yp p o G :: 2. 5 = ;C8 ^
,,r
- T a G = 0. 4 < Ic4 e {
g
?['
p t.75 (Hr H)/iOO ,
- .e
- a (4 -
lf ,
i 5 V vtRflCAL $5T-304 TUBE
'* i -
C.045 in 10 i 4.5 in. L E J 200 ssia < '
7 O G = 10-i? s 104
.7
~
3
- m - aGP, ,v -
. , t
+ i ;4 yt.
a}l w*o r
} y>^
/ vtRiiC AL h A$T(LL0f-C TUBf (Plf. >2)
_C[ C.079 in. 10 = f in. L 2000 os,e i
"/ G = i . 6 - 2 ,9 a 104 '
c,, t ! t t i i i
,0 100 1000 (H,-H), Stu/in ,
Fig.16 Comparison of Low- and High pressure :
Critical Heat Flux Data with Eq. (8)
9 --
s J~ru e + lo//is h /a , , e.
- o laudeemt/k + Wat/and Dala/c) .:-
e o 1avdermi/N,lanos Sie3e/ Da /)
~
~.
. o 7- -
tc. <
-/ famed Cor<c/cfion i
Q *
, Mod;he d co<<chliua, N -
+ f 6-- -
n N
/
o /
Ou1512 (orts la kcv3 .'
~
N g. .
q .
g e o s 8 X ! o .
k4-4 .I p e
os o
o '
t O 9 m e o ._
x Q 3 '! o8 o o
.v
$ o '
L' oo
} Oo
. Range o f Expectinenfa/ Va ria L 4 s
%2* e Poo o % <.. ale. Eye <+, e,,12 / Da h te 4.? .s o; o. o st - c.e 4 /,,.
n '~6 L O.2/25- 3.58 (A b;.W W L/Da r,
/8.6 r' 254 7 so-2/e y o., . e 7170 - iso, coo is/s -tis e'
O O I 2 .5 4 .6~
Ceku/ded Gi/ico/ Hed F/ux, Blu/Ar-G* x /d' -
FIGURE 1 EXPERIMENTAL BURNOUT DATA COMPARED TO VALUES CALCULATED FROM BASIC CRITICAL HEAT FLUX CORRELATION
~
IAEA-TECDOC-233 l
-: RESEARCH REACTOR CORE CONVERSION L FROM THE USE OF HIGHLY ENRICHED URANIUM TO THE USE OF LOW ENRICHED URANIUM FUELS GUIDEBOOK 1
I PREPARED BY A CONSULTANTS' GROUP, COORDINATED AND EDITED BY THE PHYSICS SECTION
.. INTERNATIONAL ATOMIC ENERGY AGENCY 4
8 k
i b
bkf /1 A TECHNICAL DOCUMENT ISSUED BY THE
& INTERNATIONAL ATCMIC ENERGY AGENCY, VIENNA,1980
.(!
?
Empirical Correlations Whittle and Forgan 34 measured the mass flow, exit temperature, and pressure drop corresponding to the minima in the pressure drop versus flow rate curves for subcooled water flowing (upward and downward) in narrow heated channels (width 2.54 cm, thickness 0.14 to 0.32 cm, length 40 to 61 cm) under the following conditions:
17 <Pexit < 25 psia L
83 <H- < 190 Da where La - heated length of channel Da = heated equivalent diameter of channel
=4x Channel Flow Area Channel Heated Perimeter = 2 4 WM y + g h-Based on these measurements the following correlation was proposed:
T out -Tin h
1 E R= =
(19)
Da y Tsat-Tin 1+ 0 g
\
A value of n = 25 was determined as a best fit to their data. Further discussion h of n is provided in the next subsection on bubble detachment and flow instability. f The average heat flux at onset of flow instability can be expressed in terms of .}
velocity, channel geometry, temperatures, and fluid properties:
)
Wt y 2;
_4 c " .h p Cpg U (T sat -Tin) ( 20) t.
1 The peak critical heat flux can be obtained by multiplying ic by the axial 5 11 peak-to-average factor, f' a )
1 In order to clarify the use of Eq. 19, we note the following: '
l.
The effect of channel entrance losses, which is a strong stabilizing factor 35 for the system, is not included in the correlation. Thus, the system could be more stable than the correlation predicts.
- 2. Since pressure drop characteristics are not required, the 0 accuracy of the prediction does not depend on two phase #
correlations (subcooled void f raction, pressure drop, and heat transfer coef ficient). All two phase effects are included
)k in the parameter n.
p
- 3. The phenomenon is sensitive to system pressure through the '$
saturation temperature, T sat' 4
- 4. The scatter in the Maulbetch and Griffith data 33 used by Forgan
[
and Whittle to extend their correlation to lower ratim of LH/Dg A increases to about 2 30% at LH/DH ~ 25.
[w
- = n. .a... >, a : mm-~ . ~ u+: - = San ~<--e : : ::Ma2 wa w - wa+ % wiw w wr;mn# W 'cw:w msswaw?w Wmee 4
n
- 1. 0_ -.
UNSTABLE 1's
.- ,. 5
, 9'-
E Z
-O - O Ib
'1/l]#I-+Mh T
+ +'- ~~
.E_
c, - -
STABLE Tw
+-1 f--p
[
g .6_ y
.e .L Bubble Detachment Flow Instability
{c .5_ >
T -T o Channel, k"nittle and Forgan [34] 4 out in 1 f .4 T -T 1 + n DH/LH sat in a Tube, Whittle and Forgan u
x channel, Croft [43]
.3_ n= 12 - 35 Bowring [50]
7 Tube, Maulbetsch and Griffith [33]
,, n= .,0 Costa [51]
e .2 o Channel, Waters [44]
n= 37 Levy [52]
+ Channel, Crenoble [45,46,47,48,49]
.1 -
I i 1 l I t 1 i l i 1 0 40 80 120 160 200 240 280 320 360 400 Heated Length /Equiv. Heated Diameter (L D)
H H Figure A9. Correlation for Flow Instability and Bubble Detachment O
u