Enhancement of boiling heat transfer in di-electric fluids.

104 Pages·1991·5.5 MB·en_US

by  Egger, Robert A.;Kelleher, Matthew D.

NAVAL POSTGRADUATE SCHOOL
Monterey California
,
THESIS
ENHANCEMENT OF BOILING HEAT TRANSFER
IN DI-ELECTRIC FLUIDS
by
Robert A. Egger
September 1991
Thesis Advisor M.D. Kelleher
Approved for public release; distribution is unlimited
T259716

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ival Postgraduate School (ifapplicable) 34 Naval Postgraduate School
Address (city, state, andZIP code) 7b Address (city, state, andZIP code)
onterey, CA 93943-5000 Monterey, CA 93943-5000
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Program Element No Project No Task No Work Unit Accession No
Title (includesecurity classification) ENHANCEMENT OF BOILING HEAT TRANSFER IN DI-ELECTRIC FLUIDS
Personal Author(s) Robert A. Egger
lType of Report 13b Time Covered 14 Date of Report (year, month, day) 15 Page Count
aster's Thesis From To September 1991 94
Supplementary Notation The views expressed in this thesis are those of the author and do not reflect the official policy or po-
Ion ofthe Department of Defense or the U.S. Government.
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Abstract (continueon reverse ifnecessary andidentify by block number)
Direct application oftwo-phase heat transfer in the liquid cooling ofelectronic components in flouorinated hydrocarbons
C-72), is severely inhibited by the excessive amount of superheat required to initiate nucleate boiling. To conduct an ex-
rimental study ofnucleate pool boiling ofFC-72, an experimental test chamber was constructed. This chamber utilized five
mm
rizontal platinum wires of0.05 diameter spaced 2.0 cm vertically from each other. The lowest wire was progressively
ated from the natural convection region through nucleate boiling, and a study was made on the effects ofthe boiling wake
ime on the heat transfer rate ofthe upper wires.
Distribution/Availability ofAbstract 21 Abstract Security Classification
D
unclassified/unlimited same as report DTIC users Unclassified
iName of Responsible Individual 22b Telephone (includeArea code) 22c Office Symbol
•D. KeUeher [phone] ME/Kk
' FORM 1473,84 MAR 83 APR edition may be used until exhausted security classification ofthis page
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Enhancement ofBoiling Heat Transfer
in Di-Electric Fluids
by
Robert A. Egger
Lieutenant Unitea States Navy
,
B.E. Mechanical Engineering, Cleveland State University, 1985
Submitted in partial fulfillment ofthe
requirements for the degrees of
MASTER OF SCIENCE IN MECHANICAL ENGINEERING
and
MECHANICAL ENGINEER
from the
NAVAL POSTGRADUATE SCHOOL
September 1991
ABSTRACT
Direct application of two-phase heat transfer in the liquid cooling of electronic
components in flouorinated hydrocarbons (FC-72), is severely inhibited by the excessive
amount of superheat required to initiate nucleate boiling. To conduct an experimental
study of nucleate pool boiling of FC-72, an experimental test chamber was constructed.
mm
This chamber utilized five horizontal platinum wires of 0.05 diameter spaced 2.0
cm vertically from each other. The lowest wire was progressively heated from the na-
tural convection region through nucleate boiling, and a study was made on the effects
of the boiling wake plume on the heat transfer rate ofthe upper wires.
in
CI
TABLE OF CONTENTS
INTRODUCTION
I. 1
A. HISTORICAL
1
BACKGROUND
B. 1
PREVIOUS WORK
C. 2
D. OBJECTIVES 4
EXPERIMENTAL APPARATUS
II. 5
A. DESCRIPTION OF COMPONENTS 5
1. Test Chamber 5
2. Aluminum Cover Plate 6
3. Heaters 6
4. Thermocouples 6
5. Insert Board 6
INSTRUMENTATION
B. 7
1. Platinum Wire 7
2. Power Supplies 8
3. Acquisition Unit 8
EXPERIMENTAL PROCEDURE
III. 17
PREPARATIONS
A. 17
1. Normal Warm-Up Procedure 17
2. Post Warm-up Procedure 17
DATA ACQUISITION PROCEDURE
B. 18
DATA REDUCTION
C. 18
1. Numerical Data 18
2. Fluid Property Data 20
IV. RESULTS AND DISCUSSION 22
A. INDIVIDUALLY POWERED WIRES 22
1. Natural Convection 22
2. Nucleate Boiling 23
IV