A study of the nucleate boiling of liquid nitrogen, liquid ...

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1969

A study of the nucleate boiling of liquid nitrogen, liquid argon, and A study of the nucleate boiling of liquid nitrogen, liquid argon, and

liquid carbon monoxide from atmospheric to near the critical liquid carbon monoxide from atmospheric to near the critical

pressure pressure

Craig Bauer Johler

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A STUDY OF THE

NUCLEATE BOILING OF LIQUID :N'"ITP..OGEN,

LIQUID ARGON , AND L~:r~l1ID CARBON MONOXIDE

FROH AT~10SPHERIC TO NZAR Tl-IE CRITICAL PRESSURE

BY 70~ CRAIG BAUER JOHI,ER \ \

A

THE SI S

submitted to the faculty of

THE UtHVERSI.TY OF MISSOlHU ··· ROLLA

in partial fu l fi llment of t he requireme nts f or the

DeL;ree of

MASTER OF SCIENCE IN CiiENICAL ENGINEERING

Roll a. , ~Iissouri

1963

ii

ABSTRACT

The nucleate boiling curves of three corresponding states liquids

(nitrogen, argon, and carbon monoxide) were analyzed. Each liquid was

studied at pressures ranging from atmospheric pressure to near the crit

ical pressure. Saturated liquid boiling was conducted from cylindrical

heaters in the horizontal position having diameters of 0.75 inches and

lengths of three inches. Liquid nitrogen was boiled from four differ

ent gold heat transfer surfaces; argon and carbon monoxide were boiled

from the same gold surface.

The c~itical heat flux correlation of Cobb and Park (8) was fur

ther verified ~y ~greement with the experimental critical heat flux

ratios obtained in this investigation. It was demonstrated that the

critical heat flux is a function of the heat transfer surface; and

Lnat this dependence on surface conditions should be provided for in

n:iximum heat flux correlations. Nucleate boiling curyes obtained for

liquid nitrogen illustrated that 2 chc:cnge in boiling heat transfer sur

face affects both the slope and shape of nucleat~; boil i..ng .~urves. The

nucl~~te boiling of carbon monoxide was observed to sho~ partial film

boiling along with low critical heat fluxes.

Measured over a wide range of reduced pressures, the liquid argon

critical heat fluxes were approximately 24 percent higher than liquid

nitrogen critical heat fluxes for a given surface. When compared to

the critical heat fluxes of liquid carbon monoxide, the critical heat

fluxes of liquid argon and liqt1id nitrogen averaged 176 and 130 per

cent larger i~ magnitude rcEpectively.

iii

ACKJ\OHLEDGEHENTS

The author wishes to thank the following individuals and organi

zations without whose help this study could not have been made.

Dr. E. L. Park for his great interest and ever present willing

ness to help.

Dr. 0. K. Crosser for his constructive and knowledgeable comments

in the writing of this dissertation.

Mr. G. J. Capone for his dedicated and persistent efforts towards

the finishing of this investigation.

Mr. R. T. Hontgomery for his helpful suggestions during the use

of his laboratory.

The American Chemical Society, Petroleum Research Fund, and the

N2tional 8r::ience f-oundation \vhich provided financial assistance both

to the author and to tl1e purcha8ing of the necessary equipment for

this study.

iv

TABLE OF CONTENTS

Page

ABSTRACT • • • • • ii

ACl0\l'mvLEDGEHENTS • . . iii

LIST OF ILLUSTRATIONS. v

LIST OF TABLES . • • • v

Chapter

INTRODUCTION 1

II. ::(EVIEw OF LI.TER.ATURE 4

12

IV. EXPERli\~E:t-;"'TA!~ PROCEDURE 17

v. Imsm:rs. . 19

VI. DISCUSSION • 25

Critical Heat Flux and Haximum Temperature Difference Correlations . . . . . . • • . . . . • . • . . 25

Heat Transfer Surface Effects on Nucleate Boiling. 32

Nucle:1tc Boiling of Carbon Honoxidc. . 35

VII. CONCLUSIONS. 38

39

BI BLlOC!~\ PHY 40

APPENDICi·;.';

A. CAJ,CULATK!l DATA . •

B. EXPE~IME~TAL ERROrrS 64

Vl'L\ 66

v

LIST OF ILLUSTRATIONS

Figure Page

1. A Typical Boiling Heat Transfer Curve ...... . 3

2. Pressure and Condensing System - Schematic Diagram ....... 13

3. Heat Transfer Element . . . . . . . 14

4. Reproduction of a Liquid Nitrogen Nucleate Boiling Curve at 0.1 Pr on Surface Number 4 . . . . . ..... 16A

5. Nucleate Boiling Curves fo~ Liquid ~itrogen on Heat Transfer Surface Number 1. . . . . . . . . . . . . . . 21

6. Nucleate Boiling Curves for Liquid Nitrogen on Heat Transfer Surface Number 2. . . . . . . . ....... 22

7. Nucleate Boiling Curves for Liquid Argon on Heat Transfer Surface Number 2 •.••••••••••••••• 23

8. Nuc I eate Boi 1 ing Curves fo.c Liquid C2rbon Monoxide on Heat Transfer Surface Number 2 ...•...••.. 24

9. C:::>bb and Park Maximum Heat Flux Correlation . . • • • . 26

10. Maximum Ileat Flux Correlations for Liquid Nitrogen ....... 29

11. Maximum Heat Flux Correlations for Liquid Argon . . . ... 30

12. Gen2ralized Naxirnum Temperature Difference Correlation. 31

13. Nucleate Boiling Curves for Liquid Nti:rogen on Different H2at Transfers Surfaces at 0.1 Pr . . . . . . . . . . .. 33

14. Nucleate Boiling Curves for Liquid Carbon Monoxide on Heat Transfer Surface Number 2 ................. 37

Table Page

1. Heat Tra~sfer Surfaces ...........••........ 20

1

I. INTRODUCTION

When heat is supplied to a saturated liquid, vapor begins to form

at the free surface above the liquid; and convective currents start

to circulate the heated liquid. A further increase in heat flux

causes vapor bubbles to form at specific locations on the heated sur

face. These discrete bubbles are intermittently released from the

heated surface and rise to the vapor-liquid interface. The vapor

bubbles are formed on surface anomalies called nuclei, and this phe

nomenon is known as nucleate boiling.

The nucleate boiling region is of great importance to the engi

neer because in this region large quantities of heat can be removed

with relatively low temperature difference. Nucleate boiling has

been widely used in the power industry, in refrigeration, and in re

actor cooling.

To date, there is no general correlation which will predict nucle

ate boiling behavior. It is knm11n that increased bubble production

increases the heat flux greatly, \17hile the temperature difference be

tween the boiling surface and the saturated liquid remains relatively

small. At higher temperature differences the bubble population in

creases to such an extent that the bubbles coalesce and completely

cover the surrounding surface with an unstable vapor film. This

added film resistance greatly decreases the heat transfer rate. The

maximum heat flux attained before the onset of this film boiling is

known as the critical heat flux (burnout point) because the decreased

heat transfer rate characteristic of film boiling may cause the metal

surface temperature to suddenly rise \vell above the me 1 ting point.

2

It is this dangerous situation that has caused wide interest in an

accurate prediction of the critical heat flux.

Nukiya~a (31) summarized the relationship between heat flux and

temperature difference by separation of the boiling curve into four

distinct heat transfer regions: 1) convective, 2) nucleate boiling,

3) unstable film boiling, and 4) film boiling. The four regions

are graphically illustrated in Figure 1.

r ~

I • . !

<t: -0'

X ::l ...... ~

4.1 co <lJ :I: 00 0

...:I

Convection Nucleate Boiling

A

Unstable Film Boiling

Film Boiling

Log Tempe:::-ature Difference,~ T

Figure 1 A Typical Boiling Heat Transfer Curve

' ~ ~

I t ~ ~

I I I I

1,..0

4

II. REVIEW OF LITERATURE

In order to provide a background in the field of nucleate boil

ing, the principle a~eas of study in this field have been reviewed.

Emphasis has been given to the study of the critical heat flux, but

developments in the areas of nucleation sites, bubble dynamics, mech

anisms of boiling heat transfer, and surface effects have also been

examined.

It is known that bubbles originating from nucleation sites are

a distinguishing feature of boiling heat transfer. Jacob (19) pointed

out that the boiling liquid is always slightly superheated at the

liquid-vapor interface. It is this small temperature difference be

tween the tv10 phases that causes evaporation at the interface. By

using the· analogy of a capillary tube, Jacob (19) shmved that boiling

would not start unless finite curvatures (nucleation sites) were

present.

Bankoff (2) stated that in practically all cases the appearance

of bubbles is controlled by minute quantities of gas, usually en

trapped on the solid heat transfer surface. Theoretical arguments

by Bankoff (1, 2) specify the activity of nucleation sites on the basis

of cavity geometry and liquid solid-contact angle. By studying nucle

ation from a single cavity, Griffith and Wallis (16) determined the

importance of cavity geometry. The cavity mouth dimneters defined

the superheat needed to initate boiling and the cavity shape deter

mined stability once boiling had begun. Studying nucleation from

artificial cavities, Denny (11) concluded that steep-walled cavities

with a depth-to-dimneter ratio greater than one were the most active

5

nucleation centers. Kosky (22) proposed three mechanisms \Jhich could

drive a liquid plug into a vapor nucleation site, causing the site to

be de-activated.

Clark, Strange, and Westwater (6) boiled ether and pentane from

zinc and aluminum alloys. They presented photographic evidence iden

tifying nucleation sites and found these sites to be pits with dia

meters of 0.0003 to 0.003 inches. Experimental techniques involving

scale deposits by Heled and Orell (17) facilitated the identification

and location of active sites. By use of nickel salts, Gaertner and

Westwater (14) counted active nucleation sites, and a maximum of 1130

sites per square inch was counted for sub-maximum heat fluxes. Wei

and Preckshot (40) showed detailed evidence of bubble growth from

glass capillary tubes with the capillaries serving as artificial

cavities.

Extensive study has been devoted to vapor bubbles and their re

lation to the high heat transfer coefficients found in nucleate boil

ing transfer. As stated, nucleation sites give rise to the develop

ment of bubbles. Jacob (19) found that the prod•Jct of bubble detach

ment diameter and frequency of bubble departure was essentially con

stant. Boiling with carbon tetrachloride, Denny (11) discovered that

bubble departure diameter increased significantly with increasing

temperature, while frequency remained practically constant. More

recently Ivey (18) showed that no single expression could correlate

frequency and bubble departure diameter and developed correlations

for three nucleate boiling regions: hydrodymanic region, transition

region, and thermodynamic region. Using a vibrating wire as a heat

ing surface, Nangia and Chon (30) reported shorter generating periods

6

for bubbles and smaller bubble diameters at breakoff.

Johnson, de la Pena, and Mesler (21) concluded that bubblds of

spherical shape have little contact area, small size, slow rate of

growth, and little or no delay time; while hemispherical bubbles

have large contact area, large size, fast rate of growth, and long

delay time. A change in surface position, from horizontal to verti

cal, ·h•as found by \-Jilliams and Mesler (41) to affect the delay time

of bubbles from an artificial site.

Various nucleate boiling heat transfer mechanisms have been

postulated as the result of previous studies concerning nucleation

sites and bubble dynamics. These theories are outlined by Cobb (7)

and Forster and Grief (13). Both studies dismissed the theories of

microconvection in the sublayer and latent heat transport by bubbles.

Forster and Grief favored the vapor-liquid exchange mechanism, how

ever Cobb considered the mechanism of mass transfer through the bubble

as p1·esented by Hoore and Hesler (29) to be the correct mechanism.

By substituting inert gas bubbles for bubbles produced in boil

ing, Ba~d and Leonard (3) indicated that heat transfer was most in

tensive during the time the bubble detaches from the surface. In con

trast, Chang and Snyder (4) reported that the high heat flux in nucle

ate boiling was caused by agitation due to bubble growth and not

bubble detachment.

Since nucleation sites have been found to play an important role

in boiling heat transfer, great attention has been directed toward

the condition of the heat transfer surface. Corty and Foust (9) dis

covered that for a roughened surface a significantly lower tempera

ture difference was required for a given heat flux when compared to

7

highly polished surfaces. It was also shown that heat transfer coef

ficients varied with the i~rrediate past history of boiling. Corty

and Foust reported that with increase in flux, active nuclei became

centers of patches on which boiling occurred violently. The theory

that surface roughness affects both the position and shape of the

nucleate boiling curve was confirmed by Kurihara and ~-1eyers (24),

who found that surface aging in the liquid to be boiled was essential

for reproducible runs.

Boiling from a grooved copper surface, Jacob and Fritz (20)

showed that the surface contained absorbed air and gave initially

much higher coefficients v1hich decreased \vith continued boiling.

McAdams (28) concluded that difficulties in correlating boiling data

Here due to three experimental variables: the amount of gas dissolved

in the liquid and absorbed on the heat transfer surface, impurities

and contamir~ation on the surface, and difference in experimental

technique.

Enhancement of nucleation due to suspended solids was reported

hy Elrod and Clark (12). It was believed that the suspended solids

triggered additional nucleation sites, either in the superheated

boundary layer above the heat transfer surface or on the surface it

self.

The maxiw.um heat flux point of the nucleate boiling curve has

proven to be an area of great interest. Many attempts have been

made to d2-.relop a. correlating equation for predicting the maximum

heat flux, but such r::qucttions have been used Hith only limited success.

By defining a universal bubble departure velocity near the criti

cal h2at flux, Rohsenow and Griffith (35) developed equation 1.

8

0.6 = 143 (1)

h%ere: L is the latent heat of vaporization

Pv is the vapor density

PL is the liquid density

Kutatladze (25) derived a similar equation independently by use

of dimensional analysis. It was pointed out by Zuber, Tribus, and

westwater (45) that both of the previously mentioned equations have

the same form as the equation for flooding in a bubble-cap column.

This correspondence is to be expected because of the similarity be-

tween burnout in heat transfer and flooding in mass transfer.

Zuber (43) presented equation 2, based on Helmholtz's instabil-

ity for two phase flmv involving liquid and vapor.

(Q/A)MAX 1t r PL - Pv Y4 r PL l~ = 10 g gc (2) Pv L 24 I_ Pv _I I PL+pv

~.fuere: a is the surface tension

g is the acceleration of gravity

Using experimental data from many organic liquids, Cichelli and

Bonilla (5) empirically developed equation 3.

(Q/A)MAX = Pr

Where: Pr is the reduced pressure

a is equal to 1 for clean surfaces

r:x is equal to 1.15 for "dirty" surfaces

Applying thermodynamic similarity and the Clausius Clapeyron

(3)

equation, Lienhard and Schrock (26) obtained an equation similar to

equation 3, involving the definition of a parachor.

9

Zuber (43) predicted a random scatter of ±14 percent f0r criti-

cal heat fluxes based on the hydrodynamic instability theory of un-

stable liquid wave lengths. It is interesting to note that Leinhard

and Schrock (26) reported a ±14 percent uncertainty in burnout heat

flux data, which they attributed to the inherent uncertainty in such

data as shown by Zuber (43). Gambill (15) likewise found a character-

istic randomness in critical heat fluxes which approximated that pre-

dieted by the hydrodynamic instability theory.

Contrary to these findings, Kosky (23), boiling with cryogenic

liquids, discovered peak nucleate boiling fluxes to be reproducible

+ to -1 percent about the mean critical flux. It was reported that a

dependence of the critical flux on the heat transfer surface shifted

fluxes 15 percent. The report suggested that inherent uncertainty in

pcedicting critical fluxes was in reality due only to surface varia-

bility. Sterman and Vilenma (37) also reproduced critical heat fluxes

to ±2.5 percent using diphenyl.

By use of surface deposits, Costello and Frea (10) noted that in-

creasing the wettability of the heat transfer surface reduced the base

radius of the departing surface bubbles, the deposits enabled more

li~uid to reach the heater and in turn increased the critical heat flux.

As discussed by Park (33) and Cobb (7), Frederking used a thermo-

dynamic appro&ch to predict the temperature difference at burnout. He

defined the degree of metastability as,

E = Temperature Difference at Burnout in Actual System

= (4) Theoretical Temperature Difference at Burnout

where the theoretical temperature difference at burnout might be ap-

preached in an ultraclean system.

10

Since the burnout temperature difference changes radically with

change in the microrouglmess of the surface, Park (33) extended

Frederking's work and established a reference value for each surface.

Eqcation 5 was obtained by limiting his work to corresponding states

liquids.

6 Tbo = 2.3 (l-Tr)0.64 (5)

6 Tbo reference Pr = 0.1

\Vhere: Tr is the reduced temperature.

As the critical heat flux has likewise been found to vary with

the microroughness of the surface, Cobb and Park (8) established the

reference value at a reduced pressure of one tenth and included it

in the correlation for the maximum heat flux. They made use of the

Clausis- Clapeyron equation and the assumption that the critical heat

flux is a function of the heat of vaporization which led to the devel-

opment of equation 6.

1.70 - 3.90 Tr - 0.048 :::

(Q/A)MAX

(Q/ A)~1AX p r 5 6 O.l + 5.20 Tr - 12.88 Tr

Tr 2 + 2.81 Tr3 + 2.48 Tr4

(6)

This correlation is a least squares fit of experimental nucleate

boiling results from various heat transfer surfaces and geometries

using several corresponding states fluids. The average deviation of

the correlation was reported to be 12.6 percent.

The results of studies in the areas of nucleation sites, bubble

dynamics, mechanisms of boiling heat transfer, and the critical heat

flux all point to the importance of the heat transfer surface associ-

ated with nucleate boiling. Attempts to develop a general nucleate

hailing heat transfer correlation have failed due to neglect of the

11

role of the heat transfer surface or to improper characteri~ation of

this surface. Cobb and Park (8) have eliminated the effect of the

heat transfer surface in their correlation of maximum heat flux ratios.

The purpose of this investigation is to further verify and extend

the Cobb and Park correlation by studying the nucleate boiling behavior

of the following corresponding states fluids: liquid nitrogen, liquid

argon, and liquid carbon monoxide. Specific attention will be given

to the role of the heat transfer surface on the critical heat fluxes

of these liquids. Several heat transfer surfaces 'vill be employed in

the investigation to emphasize the importance of the heat transfer

surface on the nucleate boiling curves of the previously mentioned

cryogenic liquids.

\,

12

III. ~XPERIHEi\11'AL EQUIPHENT

The experimental equipment was composed of four components: 1)

pressure and condensing system (Figure 2), 2) heating element (Figure

3), 3) electrical system, and 4) the temperature measuring system.

The pressure and condensing system used was similar to those de

scribed by Sciance (36) and Cobb (7). A one gallon autoclave, manu

factured by Autoclave Engineers, Inc., contained the heating element

and liquid pool. The vessel had a depth of twelve inches and an in

side diameter of five inches.

Pressure in the closed vessel was controlled by the amount of

vapor condensed outside the internal condenser as shown in Figure 2.

The condenser coolant, liquid nitrogen, was supplied at 235 pounds

per square inch gage from Linde LS-llOB and LS-156 dewars. A Heise

Bourdon tube ·gauge with a 16 inch dial graduated from 0 to 1000 pounds

per square inch measured the pressure of the system. The system was

protected from dangerously high pressures by a Black, Sivalls, and

Bryson rupture disc, rated at 960 pounds per square inch gauge at 72°F.

All connections shown in Figure 2 were made of 316 stainless steel.

The tubing was 0.25 inch outside diameter with a 0.065 inch wall thick

ness, and the valves were Hhitey No. 1 Series 0.25 inch valves number

IRS4-316.

Figure 3 shows the assembled heating element. Tungsten wire (0.020

inches in diameter) \vound on a 0.40 inch lava core \vith 18 threads per

inch provided the heat source. This core was insulated from the copper

cylinder by Sauereisen Electrical Resistor Cement No. 7 paste. The

copper cylinder measured 0.750 inches in outside diameter, 0.55 inches

inside diameter, and 3.00 inches in length. Tempe-rature distribution·

I I I I

Nitrogen Inlet

Nitrogen Inlet

Cooling Line

Fill Line

Cooling Coil

Autoclave

Rupture Disc

Figure 2. Pressure and Condensing System - Schematic Diagram

Preaaure Gauge

,...... w

Power Terminal

A

Copper Cylinder

ilesistor Cement 224~ungsten Resistance Winding

/. _ Lav<i Core

~hermocouple Well

Section A-A

Figure 3. Heat Tnmsfer Element

1

....... ~

15

in the heati::1g element was measured \vith three copper constanr:an thermo-

couples. These thermocouples were silver soldered into 1/16 inch holes

drilled axially into the heater wall. Positioning of the thermocouples

is clearly shown in Figure 3. A coating of metallic gold was electro-

plated onto the outer copper surface of the heater, and this gold coat-

ing served as the heat transfer surface.

Direct current power was provided by a Sorensen D.C. Power Source,

Model DCR 60-40A. The power source had an output voltage range of 0-60

volts with a current range of 0-40 amperes.

+ Voltage drop across the heating element was measured to - 0.2 per-

cent of the full scale reading of a Digitec Voltmeter, Model 201, mul-

tiple range (000.0 - 100.0 v.). Current input to the heating element

+ was measured to - 0.25 percent of the full scale reading of a Weston

Model 1 (class 50), 50 .?.mpere meter in series with the heating element.

Three thermocouples measured the temperature distribution within

the heating element as shm.,;rn in :!:i'igure 3. A fourth thermocouple mea-

sured the pool saturation temperature and was located several inches

from the heater in the liquid pool. The thermocouples \vere made of

constantan wire and copper wire (Honeywell - Type T - Model No. 9BIC -

30 A.W.G. -with fiber glass coating).

The three thermocouples leading from the heating element were each

attached to the female end of a thermocouple plug made by Marlin Hfg.

Corp. This plug arrangement allowed for easy removal of the heater

from the aut0clave. Each wire from the male end of the three thermo-

couple plugs and the pool thermocouple wire were passed out of the

vessel through a Conax Hlll-1-062-Al6-T gland with teflon sealant to a

16

liquid nitrogen reference jt1nction c1n the outside of the autoclave.

From the reference junction, the thernocouple wires were connected

to a Leeds and Northrup rotary thermocouple switch which was used in

conjunction with a Digitec Voltmeter, Hodel 451, single range (00.00-

10.00 M.V.). + The Digitec Voltmeter measured to - 0.1 percent of the

full scale reading.

The combined product errors of current and voltage for measuring

heat fluxes are ± 0.125 percent, which is approximately equal to t 50

2 Btu/hr. ft. for the large heat fluxes obtained in this investigation.

+ Temperature could be read to - 0.001 millivolts; equivalent to a tem-

perature accuracy of± 0.1°F. However, Figure 4 shows a typical re-

production of a previous liquid nitrogen nucleate boiling curve on

the same heat transfer surface. Temperature differences deviate by

an average of less than 1°F. for cor~csponding heat fluxes. Errors

of measurement in this \\fork are thoroughly discussed in appendix B.

0 .

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17

IV. EXPER_IHENTAL PROCEDURE

Before filling the autoclave, liquid nitrogen was allowed to

circulate through the internal condenser to aid in cooling the vessel

(see Figure 2). If the autoclave ~vere to be filled with nitrogen,

liquid nitrogen was charged through the fill line and into the vessel

and was vented to the atmosphere. Carbon monoxide and argon were

available in the gaseous state and were condensed inside the auto

clave by regulating the gas flow through the fill line and into the

vessel. Continued circulation of liquid nitrogen through the inter

nal condenser caused the gas to condense, until the required liquid

level was reached within the autoclave.

When the liquid level was approximately seven inches, the vessel

was closed to the atmosphere; and the system pressure controlled by

monitoring the nitrogen flow through the internal condenser. When

the desired pressure was reached, power was supplied to the heating

element. To achieve proper aging of the heat transfer surface, power

was increased until the heater passed into the film boiling region.

The pmver ~.,ras then turned off, and the heater allowed to cool to sat

uration temperature. This procedure of entering the film boiling

region was repeated each time the heater was Pxposed to the atmosphere.

With the liquid pool at the desired saturation temperature, power

was once again supplied to the heating element. Tempcra.ture, amperage

and voltage were recorded after steady state was a.chieved by adjusting

the nitrogen flow rate in the internal condenser, the power level was

raised and the next nucleate boiling point was recorded. Intermittently

18

bet·h'een points, the t11cr,nccouplc r<::cLn·ding the pool tCDJ>c>r~:lcn·c \·,'C:S

checked to observe any change in the saturation temperature. This

procedure was continued until the burnout point was attained. Once

a pressure run had been completed, the power was turned off and the

pressure was adjusted to a new value. The previous steps were re

peated at each pressure, until all of the desired ~ucleate boiling

curves for the specific liquid were recorded.

To check for reproducible results, the boiling curve at a reduced

pressure of one tenth was always the first and last boiling curve to

be studied for a given liquid. The reduced pressure of one tenth \-.'as

chosen because of the desire to carefully examine the correlation de-

veloped by Cobb and Park (8).

The critical heat flux was defined by a rapid increase in 6T.

This rapidly rising ,\T Has observed, for most ~cuns, to occur as soon

as the power was increased from the previous setting. Only in a few

instances Has the 6T found to rise suddenly after the pmver setting

had remained constant for several minutes. In the latter case the

last power setting was recorded as the critical heat flux; for the

former case the critical heat flux was recorded as an average of the

last two power settings.

19

V. RESULTS

During the course of taking experimental boiling heat transfer

data, four different heat transfer surfaces were used. Table I is

a summary of the various gold heat transfer surfaces employed. T\vo

heaters were necessary because of the failure of the heating clement

within heater number 1. An entirely new heater and heating surface

were introduted after this failure; however, both heaters were of the

same design.

A total of thirty-eight nucleate boiling runs \-Jere made while

boiling \vith liquid nitrogen, liquid argon, <1nd liquid carbon mon

oxide over a wide range of reduced pressures. Four heating surfaces

were used in taking the twenty-two liquid nitrogen boiling runs, but

only one surface (surface number 2) Has employed for the sixteen liquid

argon and liquid carbon monoxide boiling runs. Thirteen of the thirty

eight nucleate boiling runs '\vere duplications of previous runs at vari

ous reduced pressures.

Figures 5 through 8 present a number of the nucleate boiling curves

at several reduced pressures for individual boiling surfaces. The boil

ing curves for liquid nitrogen and liquid argon followed the same gener

al pattern. The slopes of the boiling curves became larger with in

creasing pressure, and the critical heat fluxes had their greatest

values at reduced pressures ranging from three to five tenths. In

constrast, the nucleate boiling curves obtained with liquid carbon

monoxide (Figure 8) were characterized by abbreviated nucleate boiling

regions and lmv critical heat fluxes. Surface number 2 yielded S-shaped

boiling curves when boiling with liquid nitrogen, liquid argon and liquid

carbon monoxide.

TABLE I

HEAT TRANSFER SURFACES

Surface number Heater number

1 1

2 2

3 2

4 2

Characteristics of the surface

20

electropleated with gold - unaltered

electroplated with gold - unaltered

Surface number 2 - boiled in tap water for 24 hours

Surface number 3 - polished with a soft cloth wheel

--· ...... _

__

...__

0 0

0 .,...;

"' 1.1'\

• •

. 0

0 0

II li

II

P-.J..c J..c

J..c p

, P-.

0 <:j

8

~ ~

.. J 0 .

0 0

c 0

0 0

c 0

0 .

. .

. .

. .

. .,...;

"" a:;

('.. "'

lf' ..::t

C"''

N

( 0"') :/+..'!

tr-(,

".tH;'O

,LS: 'xn1:...r

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• 0 II J..c p..

D>

'Cl

co • 0 II J..c 11..

0

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fj g11:re 5.

K•1cle::~ to

Bo

iling

C

urv

es fo

:r L

iqu

id

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gcn

·on

H

c::tt 'I'N

r>sfer S

urf.acc

l~mnber 1

21

0 • ~

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.... ~

0 • 0 .,...;

~

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s:: co

CJ

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t,.., •rl A

ol)

J..c 0

~

• .;..>

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(lj

1-· (i) p.. s Q

.) E--4

0 . -~ ......

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0

0

r--------------------........--~-1.]-----~-----~----·

0 0

0 0

\Q

.-l

"' l/'1

co

co .

. .

. .

0 0

0 0

0

II II

II II

II ~.

$; r-.

P-.r-. r-.

i--. r...,

0-, fl.

0 <J

0 t>

0

£:

~----·~·----~----~----~----~----~----~----~~--~~--~

0 0

0 0

0 .

. .

. .

l/'1

_j-

"' N

..--i

(Ol.:)

tz-' z '+c'l

".rt-i/lU8

I X<YL>I +

-e<-•H

fjg,_;:·8 6

. I>~r~Late

2-Y1ling

Cu

rves

fo:c U

q1

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o

n

f~c-'lt 'I'r·'H

1Sfcr

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0

22

0

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,~

0 . 0 .-l

~,.

Q . G

; c

(.) .

s.:: co

Q

r ... C.' (,...; ;, •ri ~:~

Q

0 ~

• _;::;

'L)

<'.1 r-. C

l) p

. G

0

(---1

0 . _:;[

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0

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0 0

~-<

c~"'\ U

\ 0.~

• .

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0 0

0 0

II II

II II

M

P-.H ~

f)...H 0..

0 ~

[J

c (.,"'•. . 0 II J.< 11...

D>

'.J-\ ._, . 0 !I J.. ,, .....

0

0 . ..:t ......

0 . C'J ......

0 • 0 .-

i

-----~---~----~--·--~--·-~-----~----~-----~----~--~0

0 • \1"'1

Fig

ure

7.

0 0

. ..:!"

0 • (\J

0 • .--l

1'~u~lea tc

Boi lir.g

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urv

es fo

r L

iqu

id A

rGon

on

· H

r:at T

ran

ffer Surf~ce

2

c

23 rx. 0

0 0

0 0

...-l ('()

IJ\

OJ

. 0

0 .

0 0

0 0

P-i;.; P-i;.;

P-i;.; P-l ....

~ _

G-·

_.,_.J:wew-....... "'r.~ ......

,...-~.::l;o;&""U:·•r~..._......_ ••

0 0

0 0

0 0

0 .

0 0

0

L'\

...:t (Y

") C\J

.-!

( 01

) ·'L

it • .rn; m

rr 'x

n1

if 1 B

8H

it-

G

Fit;u

re 8.

tjucle

ate

B

oilin

G C

urv

es fo

r L

iqu

id C

arbo

n M

on

ox

ide

on

Beat

Tran

sfer Su

rface N

wnber

2

24

0 . ...:t .-I

0 0

C\J r-l

0 . 0 .-I

f:r.! 0

"' (!)

0 C

) .

s:: O

J (!) ;.; (!)

Cr-.; '+-! ·r-1 A

(!)

0 ~

. +

' \..0

cl3 f...t (!) p

. s (l)

E-i

0 0

...:t

0 . C\J

0

25

VI. DISCUSSION

This study was made with the purpose of extending the knowledge

of boiling heat transfer in three areas. The first area involves the

prediction of the critical heat flux and maxiw1m temperature differ

ence for both liquid nitrogen and liquid argon. The effects of the

heat transfer surface on nucleate boiling are covered in the second area.

The third phase of study deals with nucleate boiling of liquid carbon

monoxide.

CRITICAL HEAT FLUX AND MAXIMD}1 TEMPERATURE DIFFERENCE CORRELATIONS

All critical flux data for nitrogen and argon was correlated by

using the Cobb and Park (8) maximum heat flux correlation. By using

the reduced pressure of one tenth as a reference value, the correla

tion eliminates the effect of heat transfer surface on the critical

heat flux throughout a series of pressure runs. It must be emphasized

that the heat transfer surface should remain constant during a series

of pressure runs for the correlation to be utilized.

An average error of 6.18 percent Hith a standard deviation of

18.2 percent was obtained '"hen sixteen liquid nitrogen and liquid argon

critical heat fluxes '"ere compared to the Cobb and Park equation in

Figure 9.

The series of nitrogen runs with heating surface number 1 deviates

noticeably from the Cobb and Park equation at reduced pressure of three

tenths Gnd five tenths. This deviation can probably be attributed to

a change in the heat transfer surface during boiling. Although care

was taken to properly age the heating surface before a series of runs,

26

0 1.h

1.2

1.0

..-I . 0

II

rf: o.P 0

~' " c:! t:'; ..........

·~ --.... C1 '-.•' (). 6

~ --....

>< l~ s ,.-.....

~~ -... ..._ 0' '-"

o.4

0 1'~2 .Snrf::tce 1

9 ~,i

·'2 Sl.J~fn.cc 2

0.2 8. lli

·'2 Su:rfar~e 3

8 Ar S,:rfd_ce 2

Cobb and. "Prc:.rk Co•Telation, Equation 6

0 -'-~~- __ ._ __ ,,-.!..-. ...!. • -1·-~--~--~-l..---.1--J...--~ 0 • .5 0.6 0.7 o.s 0.9 1.0

27

a chat~ge in surface conditions could have occlJrred after or during the

first nitrogen pressure run which was made at a reduced pressure af

one tenth. A premature burnout at this particular pressure would

cause the high deviation from the Cobb and Park equation. An att~mpt

to prove this argument, by reproducing the one tenth reduced pressure

run at a later date, was unsuccessful because of the failure of heater

number 1.

Figure 10 shows the accuracy of Zuber's (43) critical heat flux

correlation for liquid nitrogen, having an average experimental error

of -10 percent:; hm.;rever, the Kutatladze (25) curve is shifted upward

from the data. The correlations of Cichelli and Bonilla (5), Lienhard

and Schrock (26), and Rol,senow and Griffith (35) yield results which

sre in error by several hundred percent.

The complete failure of the five previously mentioned correlations

to predict maxim~m heat fluxes corresponding to the experimental re

sults obtaiced using liquid argon is presented in Figure 11. The Zuber

c.nd Kutatladze correlations fail to fit the CJrgon data while they pro

vide & close approximation to the nitrogen data because the surface

tension of argon is approximately ten times larger than the surface

tension of nitrogen, (see equation 2). The experimental heat flux data

yields a mean error of 11.9 percent with a standard deviation of 26.0

percent Hhen compared to the Cobb and Park equation.

For a given surface (surface number 2), the liquid argon critical

heat fluxes were approximately 24 percent higher than the liquid nit

rog0n crilisal heat fluxes. This percentage is based on nucleate

boiling runs made at reduced pressures ranging from one tenth to eight

28

tenths. Cobb (7) found the maximum heat flux to be 10 to 30 percent

higher with liquid argon than liquid nitrogen.

The data of this investigation confirms Park's (33) ma...ximtJm tern-

' perature difference correlation, equation 5. The scattering of the

data (Figure 12) can be attributed to the following sources: 1) De-

termination of the exact temperature difference at the burnout point

is difficult because of heater instability and 2) The magnitude of

the temperature difference is much smaller than that of the heat flux.

C\1 . .::

H --.. . ;S --..

C\J

375

350

325

300

275

225

200

175

150

l"'lt:; --.. c../

.-.- .. --....... . . ./ ..

I

// . ,

// (

: / 1/ ~/

-- ---

·-- + -- w- • .-- ............. 100 ·;£

75

50

0

0

EJ 0

O.l

0

N2 Surface l

N" Surface 2 c:

" Cun·e Reference

Cichelli and Bonilla Lienhard and Schrock Rohsenu11 and Griffith Ku t a tl.s.dze Zuber

\\ \

\ \ \ \

\ \ ' ..

\\ \ \ \\

29

(5) (26) (35) (25) (43)

\ - \

\\

P/P c

Figure 10. ~·hximlull Heat Flux CorrPlations for Liq_uid Nitrogen

CJ . >:::

H

-----.

350

325

300 I

--- , .............

/

I . '/ -/1 ~

I: /

I I /

I 275 I ,:

I jl _,.....- '--. I . • -...........

250 , I ·~ "

' / " I·; 225 -, /f

1/ : 2JJ :1. l (5

~ I ' .

15.0 j

100

75

50

25

0

8 Ar Surface 2

0,1 0.2 0.3

30

Cunre :RE:ference

Cichelli ~1d Bonilla (5) T~ien;1&.rd ancl Sch.cock (26) Rohseum·i and ~;riffith (35) Kutatladze (25) Zuber (43)

\

'\. \

• . \

\

\

.6.

0.5 0.6 0 '7 • I

0 Q .u o. 9 l. 0

F'F I c

:Figure ll. MaximuJn Heat Flux Correlations for LiQuid Argon

31

C\l . 0 .--1

~

<:] ....... • 0

0 co

II .

H

0 il.

r--i n 0 •rl ~

•rl ,._,

(_;

-.() . [--4

0 <

] k

0 .........

0 ..-;

G

''iS 0

•rl +

-) ·rl H

..:t

u (>

..--i N

(""\

C\? •

0 [-<

<

l) <!)

0 <!)

<] (.)

(.) 0

(.) m

r!

C"j ('J

frl c.-~

C.-; ~

H

r. H

H

;:j

;:j ;::1

;'j U

) u

) U

) U

)

•. S"l N

C

\l ,_~

"''"' z

z <

N

. 0

0 Q

<J

l>

~ ~

0

0 0

'-co

C'-

'-[) 1.1\

. .

. •

. .

..--1 0

0 0

0 0

.r.L ';?>

.J ll't 'P..J;:JdW

;),L

p;)o

np

da

Fic

rrr: 1

2.

Gen8r.".1i7.ed.

F::x:ir-•ll'Tl T

cnp

e1"!.h

're Djffcrc~;cc

Co

rrnJa

tion

32

HEAT TRANSFER SURFACE EfFECTS ON I\TUCLEATE BOILING

Four different heat transfer surfaces were utilized during the

experimental nucleate boiling runs, as indicated in Table I. Figure

13 illustrates the effect of the condition of the heat transfer sur

face on the shape and slope of liquid nitrogen nucleate boiling curves.

Relatively smooth nucleate boiling curves are associated \vith surfaces

1 and 4, but the slope of the surface 1 boiling curve is approximately

twice the slope of the boiling curve exhibited 1y surface 4. The boil

ing cu£ve obtained from surface 3 is also of greater slope than the

surface 4 curve; as stated in Table I, surface 4 is highly polished

and smoother than surface 3. Surface 2 and 3 boiling curves initially

have si~ilar slopes, but their shapes and slopes differ greatly as the

crittcal heat flux is approached.

The boiling curves derived from these surfaces confirm the con

cLJsicns reached by Carty and Foust (9); that ~~T in nucleate boiling

decreases with increased roughness and that the positions and slopes

of the boiling curves vary with roughness.

The S-shaped curve associated with surface 2 is particularly un

usual. S-shaped curves have been reported by several authors: Tang

and Rotem (38), Rallis and JaHurck (34), Van Stralen (39), and Zuber

(44); however, the observation of such curves is relatively infrequent.

Orell (32) gives further insight into the S-shaped curve by relating

its appearance to a sudden ir,crease in the nucleation site density.

Many authors- Gambill (15), Costello and Frea (10), Stermen and

Vilemas (37), Kosky (23), and Young and Hummel (42) - have indicated

the importance of the state of the heat transfer surface on the criti

cal heat flux. As mentioned, different pressurP. runs were reproduced

'"=>:j f-'•

(l4 >::! li (lJ

t-' w .

tJ ·~ .. __, f-'•:::: 1-+,)() 1-+.Jt--' (j) (j) ..::t· li ll' I

([) c+ ,.. ..... ::s (lJ 0 c+ ...-1

~· w '--"' ).l.-4 0 rD f-'• (\J

ll' t-' .

c+ f-'· .j..)

..... i1-. ,...>

t-3 CfC. li ll' 0 >-;

::s :::: <:_ en t-1 H.J<: ~ (lJ (j)

'""i en (:Q

en 1-+.J

~

U)O ~ >::! li li rl 1-+.Jt-i i1-. ll' f-'· o..a +' (lJ ~ ro en f-'· (!)

p, ~ ll' c-r ~

f-'• or-. f-.j

1-'0 Gtl

1-Q(J) li ::s

0 ::s

5.0i"

0 Svrface 1 - electrcrplated with gold

I 8. Surface 2 - electroplated with gold

4.0 .... 0 Surface 3 - Surface 2 boiled in tap water for 24 hours

@ Surface 4 - Surface 3 polished with a soft cloth wheel

3. o·-

2.0

l.O

0 ~

0 2.0 4.0 6.0 8.0

Temperature Difference, °F

10.0 12 .o

I , l

I I

I I

/j I i

l ~

14.<) ....,.: w

34

to be sure t~2t the henting surface had n0t changed during boiling.

Eight boiling curves were duplicated at various pressures on unaltered

heat transfer surfaces. Reproduction of the critical heat flux never

deviated by more than 7 percent; and the average deviation for the

eight critical fluxes reproduced was 3 percent. An inherent error

of 3 percent was calculated for this heater arrangement.

In contrast, the five nitrogen reduced pressure runs duplicated

on surfaces 1 and 2 produced an average deviation of 17.6 percent among

co~responding maxim~um heat fluxes. Similarily, a deviation of 24.0

percent was found between atmospheric critical heat fluxes on surfaces

1 and 3; ,.;rhile the ma..ximum heat flux was decreased by 16.4 percent by

polishing surface number 3.

Of the eight boiling curves duplicated on unaltered surfaces, five

wer2 not exposed to the atmosphere between checks for reproducibility

and three were exposed. This exposure did not affect duplication of

the maximum heat flux but did affect the reproducibility of the maxi

Iaum temperature difference. The reproducibility of the maximum 6.T

on the five unexposed surfaces never deviated by more than 7.2 percent,

\vith an average deviation of 4. 6 percent. The maximum !:.T on the three

exposed surfaces varied \vith an average deviation of 19.9 percent.

Frederking (27) explains this deviation by noting that in different

experiments the te;nperature difference may vary by a factor of two,

due to the amount of vapor or foreign gas trapped in surface cavities.

35

1\TtTCLEATE BOILING OF CARBON HONOXIDE

Nucleate boiling of liquid carbon monoxide gave unusual results

when comp&red to the experimental data of nitrogen and argon.

Three boiling curves were duplicated at a reduced pressure of

one tenth, and the average critical heat flux deviation was 11.3 per

cent for the same boiling surface. This high deviation might be ac

counted for by change in the heat transfer surface caused by carbon

monoxide or by the unique behavior of the carbon monoxide critical

heat flux as discussed below.

The critical heat fluxes of liquid argon and liquid nitrogen were

defined by a sudden rise in surface temperature signaling the begin

ning of film boiling. In contrast, the pressure runs of liquid car

bon monoxide, above the reduced pressure of one tenth, entered partial

film boiling at relatively lmv heat fluxes. This partial film boiling

-.;v-as characterized by a slm..:r increase in temperature difference with

tiQe at a const2nt heat flux. After several minutes had elapsed, the

last 6T \vas recorded before a rapid increase in surface temperature

marked the initiation of fully developed film boiling. The last UT

recorded varied randomly in the range of 20 to 50°F with different

pressure runs.

Boiling from a platinum surface -.;..:rith liquid oxygen, Lyon, Kosky,

and Harman (27) experienced this same phenomena of partial film boil

ing at higher pressures. They attributed this behavior to a small

section of the test element entering film boiling. It is apparent

that the variation of pressure causes a change in the normal mechan

isms of nucleate boiling for liquid oxygen and liquid carbon monoxide;

adsorption of the oxygen molecule on the bcdlin::.; surf.1cc :1t l1i;~lwr

pressures may be an explanation.

The carboa monoxide nucleate boiling runs were all obtained while

boiling from heat transfer surface number 2. This is the s:une surface

that exhibited the S-shaped boiling curves for liquid nitrogen and

liquid argon. It may be possible that surface effects other than

oxygen adsorption caused the premature film boiling obs~rved with

liquid carbon monoxide, and that these same unkn0Hn surface effects

are the source of the unique S-shaped boiling curvc>s. l\\Jclc:1te boil

ing of carbon monoxide from different heat transfer surfaces should

provide a definite answer to this question.

The carbon monoxide nucleate boiling curve associated Hith the

reduced pressure of three tenths has a very definite S-shaped appear

ance. This curve may represent the effects of an unstable transition

between the larger slope of the one tenth reduced pressure boiling

curves and the smaller sloped boiling curves at reduced pressures of

five tenths and higher.

The heat flux that initiated partial film boiling Has defined

as the critical h~at flux for carbon monoxide. Figure 14 is an en

largement of Figure 8, and both figures shaH the loH critical heat

fluxes of carbon monoxide coupled with the gradual disappearance of

the nucleate boiling region \vith increasir1g pressure.

A family of nucleate boiling pressure runs \vas made on surface

number 2 for liquid nitrogen, liquid argon, .:mel liquid carbon monoxide.

Comparison of the critical heat fluxes for these liquids shows that the

argon and nitrogen critical heat fluxes averJge 176 and 130 percent

larger in magnitude respectively, \vhen compared to the critical heat

fluxes of liquid carbon monoxide.

0 0

0 0

rl

(Y")

Ll\

CD

.

. .

. 0

0 0

0

rl rl

p...,rl rl

p..., p...,

p...,

L\ 0

0 [>

c IS

\ 0

\ 0

\ .

. 0

0

rl rl

p..., il;

0 ~

0

0 . 0 . 0 rl 37 rr..

0

" (!)

0 0

. ~

CD

(!)

(

~------J ......... _

__

,._

.!. .......... ~

-.ry~---.. J

----~~~""'•'..o-"'~~.J'il!'-~~

Ll\

C\J

0 C\J

Ll\

0 L

l\ 0

. .

. rl

rl

0

Fic:u

re 1

4.

Nu

cle

ate

B

oilin

s C

urv

es fo

r L

ic1u

id

Carb

on

M

on

ox

ide

on

Heat

Trc;,ns fe

r S

urfc>,cc

l'Tum

ber 2

0 . 0 . 0 . (\j

0

::-; (!)

'+-1 Ct-! ·~

A (!)

::-; ;_j

-P

m

::-; (!)

Pi

s (!) E--1

38

VII. CONCLUSIONS

1. Of the critical heat flux correlations tested, the Cobb and Park

(8) equation is the most accurate for the prediction of the criti

cal heat fluxes of liquid nitrogen and liquid argon.

2. Measured over a wide range of reduced pressures, the liquid argon

critical heat fluxes are approximately 24 percent higher than

liquid nitrogen critical heat fluxes for a given surface.

3. Each boiling heat transfer surface has its own characteristic boil

ing curve with respect to both shape and slope.

4. For a given surface, the critical heat flux can be reproduced to

within 3 percent at various reduced pressures; however, it may

vary as much as 25 percent among different heat transfer surfaces.

5. Exposure of the heat transfer surface to the atmosphere does not

affect the critical heat flux, but does alter the maximum temper

ature difference by an average of 20 percent.

6. In contrast to liquid nitrogen and liquid argon, the critical

heat fluxes of liquid carbon monoxide are defined by the appear

ance of partial film boiling at reduced pressures ranging from

three tenths to near the critical pressure.

7. ~1en compared to the critical heat fluxes of liquid carbon monox

ide over a wide range of reduced pressures and for a given surface,

the critical heat fluxes of liquid argon and liquid nitrogen aver

age 176 and 130 percent larger in magnitude respectively.

A 2 Are3, ft.

l'\0}1ENCLATURE

g Acceleration due to grQvity, ft./sec.2

39

gc = Conversion factor in NeHton's law of motion, lb.m ft./lb.f sec. 2

L Latent heat of vaporization, B.T.U./lb.

p = Pressure, P.S.I.

Q = Rate cf heat transfer, B.T.U./hr.

T = Temperature, 0 R or oF

!:.T = Temperature difference, (Tsurface - Tliquid)

Greek Symbols

E = Degree of metastability, defined by Equation 8

o Surface tension, lb.f/ft.

p = Density, lb./ft. 3

Subscripts

L = Refers to the liquid

r = Refers to reduced property

v = Refers to the vapor

.uax = Refers to the point 'vhere the maximum heat flux occurs

40

BIBLIOGRAPHY

l. Bankoff, S G., "Entrapment of Gns in the Spread~ng of n Liquid Over a Rough Surface," A.I.Ch.E. J., Vol. 4, 1958, p. 24.

2. Bankoff, S. G., "Prediction of Surface Temperature at Incipient Boi 1 ing," l1eat Trans fer, Chemical Engineering Progress, Symp::lsium Series, Vol. 55, A.I.Ch.E., Ne\.;r York, 1959, p. 87.

3. Bard, Y., and Leonard, E. F., "Heat Transfer in Simulated Boiling," Int. J. Heat Mass Transfer, Vol. 12, 1967, p. 1727.

4. Chang, Y., and Snyder, N. W., "Heat Transfer in Saturated Boiling," Heat Transfer, Chemical Engineering Progress, Symposium Series, Vol. 56, A.I.Ch.E., New York, 1960, p.25.

5. Cichelli, M. T., and Bonilla, c. F., "Heat Transfer to Liquids Boiling under Pressure," Trans. A.I.Ch.E., Vol. 41, 1945, p. 755.

6. Clark, H. B., Strenge, P. S., and \.Jestwater, J. W., "Active Sites for Nucleate Boiling," Heat Transfer, Chemical Engineering Progress, Symposium Series, Vol. 55, A.I.Ch.E., New York, 1959, p.l03.

7. Cobb, C. B., "A Study of Surface and Geometric Effects on the l';ucleate Boiling of Liquid Nitrogen and Liquid Argon," Ph.D. Thesis, University of Missouri at Rolla, 1967.

8. Cobb, C. E., and Park, E. L., "Nucleate Boi 1 ing - A Haximum Heat Flux Correlation for Corresponding States Liquids," A.I.Ch.E. Preprint 22, Tenth National Heat Transfer Conference, Philadelphia, Pennsylvania, August, 1968.

9. Corty, c., and Foust, A. S., "Surface Variables in Nucleate Boiling," Heat Transfer, Chemical Engineerin_g Progress, Symposium Series, Vol. 51, A.I.Ch.E., New York, 1955, p. l.

10. Costello, C. P., and Surface Burn0ut Heat

and Frea, W. J., "The Role of Capillary Wicking Deposits in the Attainment of H: gh Pool Boiling Fluxes," A.I.Ch.E. J., Vol. 10, 1964, p. 393.

11. Denny, V. E., "Some Effects of Surface ~licro-Geometry on Natural Convection and Pool Boiling Heat Transfer to Saturated Car-bon Tetrachloride," Ph.D. Thesis, University of Hinnesota, 1961.

12. Elrod, W. C., Clark, J. A., Lady, E. R., and Merte, H., "Boiling Heat Transfer Data at Lm'' Heat Flux," J. Heat Transfer, Vol. 89, 1967, p. 235.

41

13. Forster, K. E., and Grief, R., "Heat Transfer to a Boiling Liquid, Hechanisms and Correlations," J. Heat Transfer, Vol. 81, Feb. 1959, p. 43. .

14. Gaertner, R. F., and Westwater, J, W., "Population of Active Sites in Nucleate Boiling Heat Transfer," Heat Transfer, Chemical Engineerin~Progress, Symposium Series, Vol. 56, A.I.Ch.E., New York, 1960, p.39.

15. Gambill, W., "Experimental Investigation of the Inherent Uncertainty in Pool Boiling Critical Heat Fluxes to Saturated Water," A.I.Ch.E. J., Vol. 10, 1964, p. 502.

16. Griffith, P. J., and Wallis, J.D., "The Role of Surface Conditions in Nucleate Boiling," Heat Transfer, Chemical Engi~~ ing Progress, S)~posium Series, Vol. 56, A.I.Ch.E., New York, 1960, p. 49.

17. Heled, YA, and Orell, A., "Characteristics of Active Nucleation Sites in Pool Boiling," Int. J. Heat Hass Transfer, Vol. 10, 1967' p. 553.

18. Ivey, H. J., "Relationships Bet\,,een Bubble Frequency, Departure Diameter, and Rise Velocity in Nucleate Boiling," Int. J. Heat Mass Transfer, Vol. 10, 1967, p. 1023.

19. Jakob, M., Heat Transfer, Vol. 1, John Wiley & Sons, Inc., New York, 1949.

20. Jacob, M., and Fritz, W., Forsch. Gebrite Ingenieurw., 2, 1931, p. 434-447. (As reported in reference 19.)

21. Johnson, H. A. Jr., DeLaPena, J., and Hesler, R. B., "Bubble Shapes in Nucleate Boiling," A.I.Ch.E. J., Vol. 12, 1966, p. 344.

22. Kosky, P. G., 11 Nucleaticn Site Instability in Nucleate Boiling," Int. J. Heat Mass Transfer, Vol. 11, 1968, p. 928.

23. Kosky, P. G., Ph.D. Thesis, University of Calif., 3erkeley, 1965.

24. Kurihara, H. M., and Hyers, J. E., "The Effects of Superheat and Surface Roughness on Boi.ling Coefficient," A.I.Ch.E. J., Vol. 6 ' 19 60 ' p. 83 .

25. Kutateladze, S. S., Izv. Akad., Nauk., U.S.S.R., O.T.D. Tekh. Nauk, No. 4, 1951, p. 342 (A translation.)

26. Lienhard, J. II., and Schrock, V. E., "The Effect of Pressure, Geometry, and the Equation of State upon the Peak and Minimum Boiling Heat Flux," J. Heat Transfer, Vol. 85, 1963, p. 261.

42

27. Lyon, D. N., Kosky, P. G., and Harmnn, B. N., "Xucleate Boiling Heat Transfer Coefficients and Peak Nucleate Boiling Fluxes for Pure LiqtJid N2 and 02 on Horizontal Platinum Surfaces From Belmv 0.5 Atmosphere to the Critical Pressures," AdYances in Cryogenic Engineering, Vol. 9, Plenum Press Inc., New York, 1963, p. 77.

28. McAdams, W. H., Heat Transmission, Third Ed., HcGraw-Hi 11 Rook Company, Inc., New York, 1954.

29. Hoare, F. K., and Mesler, R. B., "The }feasurement of Rapid SurFace Temperature Fluctuations During Nucleate Boiling of Water," A.I.Ch.E. J., Vol. 7, Dec. 1961, p. 620.

30. Nangi.a, K. K., and Chon, W. Y., "Some Observations on the Effect of Interfacial Vibration on Saturated Boiling Heat Transfer," A.I.Ch.E. J., Vol. 13, 1967, p. 872.

31. Nukiyama, S. J., Soc. Mech. Engr's. (Japan), Vol. 37, 1931, p. 367. (From reference 33)

32. Orell, A., "On S-Shaped Boiling Curves," Int. J. Hasb Heat Transfer, Vol. 10, 1967, p. 967.

33. Park, E. L. Jr., "Nucleate and Film Boiling Heat Transfer to Methane and Nitrogen from Atmospheric to the Critical Pressure," Ph.D. Thesis, University of Oklahoma, 1965.

34. Rallis, C. J., and Ja~vurek, H. H., nLatent Heat Transport in Saturated Nucleate Boiling,'' Int. J. Heat Mass Transfer, Vol. 7, 1964, p. 1051.

35. Rohsenow, H. M., and Griffith, P., "A Correlation of Haximum Heat :Flux Data for Boiling of Satur.Jted Liquids," Hee1t Transfer, Chemice_l__Engineering Pr0gress, Symposivm Series, Vol. 52, A.I.Ch.E., Ne'v York, 1956, p. 47.

36. Sciance, C. T., Ph.D. Thesis, University of Oklahoma, 1966.

37. Sterman, L. S., and Vilemas, Y. U., 1''Ihe Influence of the State of the He<J.ting Surface on Heat Transfer at Boiling," Int. J, Heat Mass Transfer, Vol. 11, 1968, p. 347.

38. !ang, S. I., and Rotem, z., "A Secondary Boiling Instability," Can. J. Ch_~· En~, Vol. 43, 1965, p. 355.

39. Van Stralen, S. J., "Heat Transfer to Boiling Binary Liquid Mixtures, Part III," Br. Chern. Engng., Vol. 6, 1961, p. 834.

40. Wei, c., and Preckshot, G. W., "Photographic Evidence of Bubble Departure from Capillaries During Boiling, •: Chemical Engineering Science, Vol. 19, p. 838.

43

41. Hilliams, D. D., and i-Iesler, R. B., "The Effect of Surf<1cc Orientation on Delay Time of Bubbles from Artificial Sites During Nucleate Boiling," A.I.Ch.E. J., Vol. 13, 1967, p. 1020.

42. Young, R. K., and Hummel, R. L., "The Burnout of Surfaces Having Precise Arrays of Active Sites," A.I.Ch.E. Preprint 23, Tenth National Heat Transfer Conference, Philadelphia, Pennsylvania, August, 1968.

43. Zuber, N., Trans. A.S.M.E., Vol. 80, 1958, p. 711.

44. Zuber, N., "Recent Trends in Boiling Heat Transfer Research Part 1: Nucleate Pool Boiling," Applied Mechanics RevieHs, Vol. 17, 1964, p. 664.

45. Zuber, N., Tribus, M., and WestHater, J. W., "The Hydr·odynamic Crisis in Pool Boiling of Saturc:ted and Subcooled Liquids," U.S. At. Energ~ Comm., AECU-4439, p. 196, 1959.

TABLE A-I l\'l.TCLEATE

TABLE A-II NUCLEATE

TABLE A-III NUCLEATE

TABLE A-IV NUCLEATE

TABLE A-V NUCLEATE

TABLE A-VI NUCLEATE

APPENDIX A

CALCULATED DATA

BOILING NITROGEN DATA




SURFACE NUMBER 1

SURFACE NLJNBER 2

SURFACE 1\'UMBER 3

SURF ACE :t'-.'lTHBER 4

BOILING ARGON DATA SURFACE NUMBER 2

44

BOILING CARBON MONOXIDE DATA SURFACE NUMBER 2

th1C:LEA'l'E BOILING l\"TITROGEN DATA ON SURFACE ~l.JNBER 1

Date - 6-27-67 Saturation Temperature 138.7°R

Saturation Pressure 14.2 P.S.I.A.

Q/A (10)-4 1?.:.!...::1. /~.E.!...Jt. 2

t:,.T Op

6.4 10.5 13.4 15.4 16.4 16.6

0.243 0.773 1.336 1.942 2.600 3.160 3.500 B-..::rnout Point

Date - 4-18-68 SatDration Temperature 160.7°R

S3turation Pressure 49 P.S.I.A.

Q/A (10)-4 6T B. t ._~jhr. ft 2 oF

0.241 3.6 0.670 5.4 1.200 6.0 1.690 7 .1+

2.130 8.2 2.670 9.0 3.020 9.7 3.520 10.4 3.360 10.8 4.060 11.2 4.260 Bu!'nO\Jt Point

TABLE A-I .::ontinued


Satur2tion Pressure 148 P.S.I.A.

Q/A (10)-4 6T B.t.u./hr. ft.2 oF

0.249 2.9 0.663 3.6 1.150 4.1 1.694 5.0 2.220 5.8 2.720 6.1 3.270 6.3 3.830 6.7 4. 200 6.8 4.450 7.4 4.850 7.6 4.9~0 7.7 5.080 7.6 5.650 8.1 6.320 8.6 6.470 :Bt.:rnout

Date - 6-6-68

Saturation Temperature 187.2°R Satu~ation Pressure 1~8 P.S.I.A.

Q/A (10)-4 2

.6.T ] . .:.t . u .:J_hr. ft. oF

0.252 2.0 0.769 4. 7 1. 313 5.6 1.940 6.8 2.520 5.9 3.220 5.6 3.860 5.3 4.410 5.6 5.070 5.6 5.690 6.0 5.970 6.1 5.160 6.1 6.230 6.2 6.280 6.2 6.500 Burnout

46

Point

Point

TABLE A-I continued


Saturation Pressure 148 P.S.I.A.

Q/A (10)-4 B.t.u./hr. ft.2

0.146 0.588 1.120 1.593 2.090 2.550 3.030 3.700 4.400 5.160 5.960 6.170 6.250 6. 320

1.2 1.8 2.6 3.1 3.5 3.6 3.6 4.0 4.6 5.0 5.6 5.7 5.8 Burnout Point

Date - 5-7-68 Saturation T~mperature 202.9°R

Sat0ration Pressure 246 P.S.I.A.

Q/ A (10) -4 " B.t."cJ./hr. ft.L ---~--

0.258 0.657 1.200 1.735 2.220 2.630 3.120 3.650 4.110 4.560 5.000 5.590 5.980

1.2 2.7 4.5 5.6 6.0 5.8 5.6 5.0 5.2 5.6 6.0 6.8 Burnout Point

47

L~8

TABLE A-I continued

Date - 6-6-68 Saturation Temperature 202. 9°R


Q/A (10)-4 2

6T B. t. u. /hr. ft. OF

0.135 1.5 0. 613 2.1 1.105 2.8 1. 622 3.2 2.090 3.3 2.520 3.7 2.970 3.9 3.620 4.3 4.290 4.8 4. 780 4.8 5.180 5.0 5.590 5.3 5.800 5.5 5.950 5.6 6.050 5.7 6.150 Burnout Point

Date - 5-7-68 Saturation Tegperature 218.9°R


Q/A (10)-4 2

6T I3. t. u . /hr. ft. OF

0.085 1.2 0.333 1.4 0.525 1.7 0.750 2.0 0.966 2.2 1.085 2.5 1.400 2.6 1.601 2.9 1. 810 2.9 2.050 3.0 2.260 3.3 2. 41+0 3.4 2.500 Rurno·ut Point

TABLE A-I continued



Q/A (10)-4 B.t.u./hr. ft. 2

0.046 0.208 0.432 0.629 0.742 0.909 1.180 1.382 1.562 1.680 1.850

0.3 0.4 0.7 0.8 0.9 1.1 1.4 1.6 1.7 1.6 BurP.out Point

Date - 5-8-68 SaturAtion Temperature 225.1°R

S:turation Pressure 467 P.S.I.A.

0.022 0.168 0.319 0.451 0.574 0.662 0.730

0.4 0.4 0.4 0.4 0.5 0.9 0.9 Bur~out Point

49

TABLE A-II

l\'1JCLEATE BOILING NITROGEN DATA ON SURFACE NUMBER 2

Date - 8-8-68 S~turation Temperature 160.7°R


Q/A (10)-4 2 B.t.u./hr. ft.

.6.T oF

1.7 3.8 6.3 8.3 9.8

10.8 11.9 12.2 11.8 11.6 11.4 11.5

0.117 0.608 1.080 1.613 2.130 2.600 2.990 3.320 3.660 3.l80 3.850 3.950 4.050 Burnout Point

Date - 8-8-68 Satu1ntion Temperature 160.7°R


Q/A (10)-4 2 6T

B. t .u ~lhr. ft. oF

0.124 3.8 0.619 6.8 1.085 8.0 1.605 9.8 2.110 11.0 2.630 12.0 3.020 11.9 3.380 11.5 3.540 11.2 3.660 11.2 3. 8!+0 Burnout ?oint

50

TABLE A-II continued

Date - 8-8-68 Saturaticn Temperature 187.2°R


Q/A (10)-4 2 .£:..!.:. u. /hr. ft.

0.203 0.603 1.002 1.483 2.020 2.600 3.120 3.820 3.970 4.070 4.150 4.240 4.360

1.5 3.0 5.1 6.4 8.3 9.5

10.5 10.6 10.4 10.1 9.8 9.5

Burnout Point

Date - 8-8-68 Satur~tion Temperature 202.9°R


Q/A (10)-4 2 A.:_l_._u. /1-~~f~-·

0.146 0.545 0.963 1.480 1. 980 2.500 3.000 3.420 3.690 3.930 4.030

1.3 3.1 4.2 5.8 7.4 8.2 9.1 9.5 9.6 9.6

Bur11out Point

51

TABLE A-II continued

Date - 8-8-68

Saturation Temperature 218.9°R Saturation Pressure 394 P.S.I.A.

Q/A (10)-4 2 B.t.u./hr. ft.

0.078 0.288 0.683 1.165 1.510 1. 910 2.200 2.290

0.7 1.6 2.0 2.2 2.4 2.5 2.5

· Burnout Point

Date - 8-8-68 Saturation Tcnpcrature 221.4°R


Q/A (10)-4 2

_!)~~Jh~~

0.162 0.281 0.495 0.690 0.932 1.148 1.455 1.650 1.860 1. 915

!':IT Op

1.8 2.3 2.6 2.8 2.7 2.9 3.0 3.0 3.1 Burnout Point

52

TABLE A-III

1\LJCLEATE BOILING NITROGEN DATA 0~ SURF,\CE l\'VHBER 3



Q/A (10)-4

.£:~'!./hr. ft. 2

5.1 8.2 9.4

10.1 11.0 12.1 12.8 13.0

0.127 0.508 0.919 1.320 1. 740 2.160 2.460 2.570 2.640 Burnout Point



Q/A (10)-4 /:,T B.t.u./hr. ft. 2 Op

0.279 6.5 0.763 8.3 1. 210 10.0 1. 760 12.2 2.260 13.2 2.340 13.3 2.420 13.4 2.490 Burnout Point

53

TABLE A-III continued



Q/A (10)-4 2 B. t .u. /hr. ft.

3.8 5.5 8.0 9.8

10.8 ll.5 12.3 13.4 14.3

0.149 0.485 1.150 1. 995 2.590 3.120 3.520 3.760 3.700 3.790 Eurn<'l.Jt Point



Q/A (10)-4 6T B.t.u./hr. ft. 2 OF

0.188 4.8 0.630 6.8 1.050 8.0 1.850 10.4 2.500 11.5 2.980 12.5 3.430 13.7 3.440 14.3 3.520 14.4 3.630 14.9 3.700 Burnout Point

TABLE A-IV

~~CLEATE BOILING NITROGEN DATA ON SURFACE NUMBER 4



Q/A (10)-4 2 6T B.t.u./hr. ft. Op

0.219 5.0 0.733 7.8 1.200 9.8 1.970 12.2 2.520 14.2 2.780 16.4 2. 770 16.2 2.870 16.6 2.940 16.8 3.030 17.7 3.140 Burnout

Date - 9-5-68 Saturation Te~perature 160.7°R


Q/A (10)-4 2 _l).t.u./h_!'. ft.

5.1 7.9

11.6 13.1 15.3 16.5 16.8 17.4 !8.2

Point

0 .1+10 0.878 1.620 2.100 2.540 2.780 2.940 3.030 3.090 3.100 Burnout Point

55

TABLE A-V

NUCLEATE BOILING ARGON DATA ON SURFACE ~~1BER 2

Date - 7-6-68 Saturation TemperatuLe 192. 0 R


Q/A (10}-4 2 B.t.u./hr. ft.

6T Op

5.8 8.6

11.4 12.7 16.9 18.4 15.4

0.339 1.059 1.900 2.660 3.440 4.210 4.670 5.350 Burnout Point

Date - 8-1-68 Saturation Temperature 192. 0 R


Q/A (10)-4 6T B.t.u./hr. ft. 2 Op

0.348 3.6 1.045 8.8 1. 788 10.9 2.460 13.3 3.010 13.7 3.420 14.0 3.680 13.9 4.100 13.3 4.350 13.4 4.560 12.9 4. 780 Burnout Point

56

TABLE A-V continued



Q/A (10)-4 2 B.t.u./hr. ft.

0.343 1.226 2.390 2.950 3.390 3.970 4.230 4.540 4.650 4.800

5.2 9.8

13.5 14.6 14.6 14.6 14.0 13.5 13.9 Burnout Point



Q/A (10)-4 2 B. t ·-~-=.Lhr. ft.

0.301 1.030 1.895 2. 770 3.560 4.230 4. 780 5.120 5.850

3.4 4.6 5.6 6.2 6.9 7.3 6.4 6.0 Burnout Point

57

TABLE A-V continued


Saturation Press~re 352 P.S.I.A.

-4 Q/A (10) 2

B. t. u. /hr_. ft.

0.293 0.974 1.800 2.660 3.460 3.840 4.150 4.410 4.410 4.650

3.6 5.9 7.3 8.0 8.5 8.6 8.5 8.5 8.4 Burnout Point

Date - 8-1-68 Saturation 7emperat~re 262. 0 R


Q/A (10)-~~ 2 B.t.u./hr. tL. ---·

0.029 0.112 0.231 0.365 0. 525 0.701 0.859 1.200 1.440 1.700 2.030 2.220 2.430 2.630 2.850 3.000

1.8 2.3 2.8 3.1 3.3 3.4 3.5 3.8 3.8 3.9 4.0 4.0 4.0 4.1 4.1 Burnout Point

58

TABLE A-V continued

Date - 8-1-68 Saturated Temp~rature 268. 0 R

Saturated Pressure 634 P.S.I.A.

Q/A (10)-4 2 B.t.u./hr. ft.

0.214 0.354 0.615 0.915 1.123 1.309 1. 372 1.681 1. 810 1.900

1.8 1.8 1.8 2.0 2.1 2.1 2.1 2.2 2.2 Burnout Point

Date - 8-1-68 Saturated Temperature 270. 0 R

Saturated Pressure 670 P.S.I.A.

Q/A (10)-4 B.t.u./hr. ft. 2

0.267 0 .41~4 0.615 0. 710 0.840 0.925

1.7 1.6 1.7 1.5 1.7 Burnout Point

59

TABLE A-VI

i:\LJCLEATE BOILING OF CARBON HONOXIDE DATA SURF ACE NUHBER 2



Q/A (10)-4 2 B. t.u. /hr. ft.

0.342 1.170 1.948 2.930 3.700 4.500 5.080

5.0 8.3

1.0.1 10.9 12.2 12.4 11.9 Bt1rnout Point

D<=~te - 8-8-68 Saturation Temper3ture 175.5°R


Q/A (10)-4 B. t. u: /hr. ft. 2

0.117 0.608 1.080 1.613 2.130 2.600 2.990 3.320 3.660 3.780 3.850 3.950 4.050

1.7 3.8 6.3 8.3 9.8

10.8 11.9 12.2 ll.8 11.6 11.4 ll.S Burnout Point

60

TABLE A-VI continued



Q/A (10)-4 .0T B. t.u. /hr. ft. 2 OF

0.124 3.8 0.619 6.6 1.085 8.0 1.605 9.8 2.110 11.0 2.630 12.0 3.020 11.9 3.380 11.5 3.540 11.2 3.660 11.2 3.840 Burnout



Q/A (10)-4 2 B.t.u./hr. ft.

2.3 3.3 4.1 4.7 5.0 3.8 4.4 4.9

Poi;tt

0.078 0.170 0.330 0.733 0.990 1. 328 1.590 1.858 2.100 6.0 Partial Film

61




Q/A (10)-4 B.t.u./hr. ft. 2

0.072 0.249 0.438 0.695 0.928 1.261 1.511

1.5 2.0 2.8 3.7 4.8 7 .o 9.1 Partial Film



Q/A (10)-4 ~~1}__./h~ft. 2

0.065 0.124 0.204 0.348 0.459 0.646 0.746

1.0 1.7 2.4 3.5 4.8 7.0 7.9 Partial Film

62




Q/A (10)-4 2 B. t. u. /hr. ft.

0.053 0.141 0.270 0.373 0.488

0.9 1.3 1.4 1.8 2.6 Partial Film

Date - 8··2-68 Saturation Ter..pcratore 240. 8°R


Q/A (10)-4 2 B.t.u./hr. ft.

0.009 0.039 0.077 0.1.+6 0. 21+6 0.376 0.491 0.585 0.685 0.765

0.4 0.6 0.6 0.6 0.6 0.9 1.3 1.6 2.4 3urnout Point

6.3

APPENDIX B

EXPERI.HENTAL ERRORS

64

•

65

As noted, the equipment and apparatus discussed in this study

are v2ry similar to that used by Park (33) and Cobb (7). The error

analysis developed in these references should be referred to for

detailed study of errors.

Current and voltage could be read to within± 0.125 amperes and

± 0.01 volts respectively. The combined product errors are ± 0.125

percent. Temperature could be read to± 0.001 millivolts which is

+ equivalent to a temperature accuracy of - 0.1°F.

Both pool thermocouple and heater thermocouples were checked for

calibration, when no heat flux was applied, by using vapor pressure

data. Due to the resistance of the thermocouple plug and wires, an

inherent positive error of approximately 1°F was noticed. This error

\vas subtracted from thermocouple readings at each heat flux; and the

6T \vas then unaffected by this error, since the error was due to re-

sistance outside of the heating system and was eliminated by sub-

traction. During boiling, the three thermocouples within the heater

differed from 1 to 2°F depending on the intensity of the heat flux.

+ Pressures were measured accurately to - 1 pound per square inch.

66

VITA

Craig Bauer Johler, the son of Mr. and Hrs. Walter W. Johler,

was born August 12, 1945, in Alton, Illinois.

He attended both elementary and secondary schools in the Roxana,

Illinois, school system. After graduation from Roxana Community High

School in June of 1963, he entered the University of Missouri School

of Mines and Metallurgy in the fall of 1963. He received his Bachelor

of Science in chemical engineering in June, 196 7; and enrolled in the

graduate school of the University of Hissouri - Rolla in the fall of

1967.

A study of the nucleate boiling of liquid nitrogen, liquid ...

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