The Determination of Thermal Conductivities of Liquids by a Modified Hot Wire Method

55 Pages·2.409 MB·English

by  McNall, Preston Essex, Jr

PURDUE UNIVERSITY
THIS IS TO CERTIFY THAT THE THESIS PREPARED UNDER MY SUPERVISION
Preston Essex McNall, Jr.
BY
The Determination of Thermal Conductivities
ENTITLED
of Liquids by a Modified Hot Wire Method
COMPLIES WITH THE UNIVERSITY REGULATIONS ON GRADUATION THESES
AND IS APPROVED BY ME AS FULFILLING THIS PART OF THE REQUIREMENTS
FOR THE DEGREE OF
Doctor of Philosophy
Professor in Charge of Thesis
Head of School or Department
y fl p*. / nÆL
TO THE LIBRARIAN:
THIS THESIS IS NOT TO BE REGARDED AS CONFIDENTIAL.

THE DETERMINATION OF THERMAL CONDUCTIVITIES
OF
LIQUIDS BY A MODIFIED HOT WIRE METHOD
A Thesis
Submitted to the Faculty
of
Purdue University
by
Preston Essex McNall, Jr.
In Partial Fulfillment of the
Requirements for the Degree of
Doctor of Philosophy
June, 1951
ProQuest Number: 27714271
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VITA
Preston Essex McNall, Jr. was born on June 8, 192) at Madison,
Wisconsin, He attended the Nakoma Grade School and the West Side High
School, both public schools of Madison. He entered the University of
Wisconsin in September, 1941. In June, 1944 his education was inter-
up ted by a call to military service. He served as an officer in the
Civil Engineers Corps of the Navy from January, 194) until his release
to inactive duty in July, 1946. One year of hie service career was
spent overseas in the Pacific area.
He was appointed Instructor of Mechanical Engineering at the
University of Wisconsin in September, 1946 and served one academic year
in that capacity. He earned his Bachelor of Science degree in Mechanical
Engineering in June, 1947.
In September, 194? he received an appointment of part time
Graduate Assistant in Mechanical Engineering at Purdue University, and
he entered the Graduate School of Purdue at that time. He held that
position until June, 1949» when he received the degree of Master of
Science in Mechanical Engineering.
In September, 1949 he was awarded a Purdue XR Fellowship for
work on his doctorate. He holds that position at present.
ACKNOWLEDGEMENTS
The author wishes to express his appreciation for the help and
encouragement offered by Dr. W. L. Sibbitt, who directed this project,
and by Drs. G. R. St. Clair, D. 0. Hamilton and J. E. Brock who cheer­
fully spent countless hours of their time in consultation. J. R. Woolf's
cooperation in calibration of the apparatus was indispensable.
table of contents
Page
NOMENCLATURE
ABSTRACT
INTRODUCTION...... 1
LITERATURE SURVEY..................... 2
THEORETICAL CONSIDERATIONS..........................................6
DESCRIPTION OF APPARATUS.......................................... 9
EXPERIMENTAL PROCEDURE............... *4
ERRORS AND ACCURACY............................................... 16
Measurement of the Apparatus Dimensions....... 16
Electrical Measurements. .................. 16
Temperature Measurements...... «.............. 17
The Calibrated Apparatus Constant............................... 18
The Measured Thermal Conductivity......... 18
Convection................................. *19
RESULTS................................... 20
DISCUSSION OF RESULTS..................... 22
RECOMMENDATIONS............... 26
APPENDIX A. Calibration of the Tungsten Filament as a
Resistance Thermometer......... 27
APPENDIX B. Calibration of the Apparatus for Use as a
Secondary Method...................................29
APPENDIX C* Kelvin Bridge Corrections. ............ )1
APPENDIX D. Sample Calculations. ...................... .))
APPENDIX E. Calculation of the Theoretical Apparatus Constant C^.«..)9
APPENDIX F. Calculation of the Product of Grashof1 s Number and
Prandtl1 e Number ..... 4o
BIBLIOGRAPHY................................................ 4)
LISTS OF TABLES AND FIGURES
List of Tables
Table Page
1. The Thermal Conductivities of Some of the More
Recent Organic Liquids.................. *........ *........ 21
2. Data on Thermal Conductivity from the Literature
for Comparison............................................ 22
5. Values of the Calibrated Apparatus Constant C at the
Three Test Temperatures..................... 29
4. Values of Thermal Conductivity of Olive Oil and Glycerine
Used to Obtain the Calibrated Apparatus Constant C. ......50
5. Observed Data for a Test Run on Aroclor #12)2 at
Zero Degrees Centigrade................................ ))
6. Data for Plot of Heat Flow vs. Resistance for a Test Run
on Aroclor #12)2 at Zero Degrees Centigrade...... ...... . )7
7- Some Properties of the Test Liquids at the Highest
Test Temperatures................... 41
8. The Product of Grashof'a Number and Prandtl ' s Number for
the Test Liquids at the Highest Test Temperatures.......... 42
List of Figures
Figure Page
1. Test Apparatus Detail ........ 10
2. Power Supply and Measuring Circuit............. 1)
). Kelvin Bridge Circuit........................................ )2
4. Data for Test Run on Aroclor #12)2 at 0° C.................... )6
NOMENCLATURE
A Area, ft2 or on?
a A constant
b A constant
0 = The calibrated apparatus constant, cm
Ct The theoretical apparatus constant, cm
Cp Specific heat at constant pressure, B per lb per F
D = Diameter, ft or cm
E s Electrical potential, volts
f z Designation of a function
g = Acceleration of gravity, ft per eec^
h Film coefficient of heat transfer, B per hr per ft/* per F or
cal per see per czn£ per 0
i Electrical current, amperes
k Thermal conductivity, B per hr per ft per F or cal per see per cm
per 0
1 - Length, ft or cm
M A constant
2 3
%r
' ^#2 /
%u Nuseelt's number, )
Npr Prandtl1 s number,
q = Heat transfer rate by conduction, B per hr or milliwatts
q© Heat transfer rate by convection, B per hr or milliwatts
qt Total heat transfer rate, B per hr or milliwatts
R z Electrical resistance, ohms
Ro Electrical resistance at zero G, ohms
r Radius, ft or cm
NOMENCLATURE CONTINUED
t = Température, F or C
A t r Temperature difference, F or C
v r Designation of a function
x z Distance, ft or cm
oC = Resistivity coefficient, ohms per ohm per 0
Coefficient of thermal expansion, ft) per ft) per F or
& =
resistivity coefficient, ohms per ohm per 0*
Density, lb per ft)
f> =
Viscosity, lb per ft per hr
-