Liquid cooling with phase change has been demonstrated to be a very efficient technique for thermal management of electronics because it has the potential to achieve high heat transfer coefficients compared to single phase liquid cooling. Previous studies on liquid immersion cooling with fluorocarbons have shown the effectiveness of boiling enhancement structures in lowering boiling incipience, raising the critical heat flux and reducing evaporator size. Two-phase thermosyphons are an alternative to liquid immersion cooling, where phase change liquid cooling can be implemented within a closed loop device. The present study involves a two-phase thermosyphon with boiling enhancement structure in the evaporator, which is subjected to sub-atmospheric pressures for lowering the saturation temperature of the working fluid. The objective of the present research is to provide a detailed understanding of the effect of liquid fill level on boiling of water with enhancement structures at sub-atmospheric pressures. The study will take into account the influence of system pressure and enhancement structure geometry on the boiling heat transfer. Experiments were performed at three different pressures, 9.7 kPa, 15 kPa and 21 kPa using a stacked enhancement structure with three different geometries (1, 4 and 6 layers), corresponding to three different liquid fill levels. The results are compared with a baseline study on sub-atmospheric pressure boiling from a plain surface at similar liquid-fill levels.

1.
Tengblad
N.
and
Palm
B.
,
1996
,
External two phase thermosiphons for cooling of electronic components
,
International Journal of Microcircuits and Electronic Packaging
,
19
(
1)
,
22
29
.
2.
Palm
B.
and
Tengblad
N.
,
1996
,
Cooling of electronics by heat pipes and thermosyphons - A review of methods and possibilities
,
National Heat Transfer Conference
, HTD-Vol 329, Volume
7
,
97
108
.
3.
Ramaswamy
C.
,
Joshi
Y.
,
Nakayama
W.
and
Johnson
W. B.
,
1998
,
Performance of a compact two-phase thermosyphon: Effect of evaporator inclination, liquid fill volume and contact resistance
,
Proceedings of the 11th International Heat Transfer Conference
, Vol.
2
, Kyongju, Korea,
127
132
.
4.
Ramaswamy
C.
,
Joshi
Y.
,
Nakayama
W.
and
Johnson
W. B.
,
1999
,
Compact thermosyphons employing microfabricated components
,
Microscale Thermophysical Engineering
,
3
,
273
282
.
5.
Ramaswamy
C.
,
Joshi
Y.
,
Nakayama
W.
and
Johnson
W. B.
,
1999
,
Thermal Performance of a Compact Two-Phase Thermosyphon: Response to Evaporator Confinement and Transient Loads
,
Journal of Enhanced Heat Transfer
,
6
,
279
288
.
6.
Ramaswamy, C., Joshi, Y., Nakayama, W. and Johnson, W. B., 2000, Combined effects of sub-cooling and operating pressure on the performance of a two-chamber thermosyphon, IEEE Transactions on Components and Packaging Technologies, 61–69, March 2000.
7.
Yuan, L., Joshi, Y. K. and Nakayama, W., 2000, Effect of condenser location and imposed circulation on the performance of a compact two-phase thermosyphon, Proceedings of the International Conference on Heat Transfer and Transport Phenomena in Microscale, Banff, Canada, 2000, 304–311.
8.
Webb, R. L. and Yamauchi, S., 2001, Thermosyphon concept to cool desktop computers and servers, Proceedings of the International Electronic Packaging Technical Conference and Exhibition, 2001, Kauai, Hawaii.
9.
Garner, S. D. and Patel, C. D., 2001, Loop thermosyphons and their applications to high density electronics cooling, Proceedings of the International Electronic Packaging Technical Conference and Exhibition, 2001, Kauai, Hawaii.
10.
Yuan, L., Joshi, Y. and Nakayama, W., 2001, Effect of condenser location and tubing length on the performance of a compact two-phase thermosyphon, Proceedings of 2001 International Mechanical Engineering Congress and Exposition, ASME, November 11-16, New York, NY.
11.
Haider
S. I.
,
Joshi
Y. K.
and
Nakayama
W.
,
2002
,
A natural circulation model of the closed loop, two-phase thermosyphon for electronics cooling
,
Journal of Heat Transfer
,
124
,
881
890
.
12.
Pal
A.
,
Joshi
Y.
,
Beitelmal
M. H.
,
Patel
C. D.
and
Wenger
T.
,
2002
,
Design and performance evaluation of a compact thermosyphon
,
IEEE Transactions on Components and Packaging Technologies
,
25
(
4)
,
601
607
.
13.
Nakayama
W.
,
Daikoku
T.
,
Kuwahara
H.
and
Nakajima
T.
,
1980
,
Dynamic model of enhanced boiling heat transfer on porous surfaces, Part I: Experimental Investigation
,
Journal of Heat Transfer
,
102
,
445
450
.
14.
Oktay
S.
,
1982
,
Departure from natural convection (DNC) in low-temperature boiling heat transfer encountered in cooling micro-electronic LSI devices
,
Heat Transfer
- 1982, vol.
4
,
113
118
.
15.
Bergles
A. E.
and
Chyu
M. C.
,
1982
,
Characteristics of nucleate pool boiling from porous metallic coatings
,
Journal of Heat Transfer
,
104
,
279
285
.
16.
Marto
P. J.
and
Lepere
V. J.
,
1982
,
Pool boiling heat transfer from enhanced surfaces to dielectric fluids
,
Journal of Heat Transfer
,
104
,
292
299
.
17.
Nakayama, W., Nakajima, T. and Hirasawa, S., 1984, Heat sink studs having enhanced boiling surfaces for cooling of microelectronic components, ASME Paper No. 84-WA/HT-89.
18.
Anderson
T. M.
and
Mudawar
I.
,
1989
,
Microelectronic cooling by enhanced pool boiling of a dielectric fluorocarbon liquid
,
Journal of Heat Transfer
,
111
,
752
759
.
19.
Gebhart
B.
and
Wright
N.
,
1988
,
Boiling enhancement of microconfigured surfaces
,
International Communications of Heat and Mass Transfer
,
15
,
141
149
.
20.
Wright
N.
and
Gebhart
B
,
1989
,
Enhanced boiling on microconfigured surfaces
,
Journal of Electronic Packaging
,
111
,
112
120
.
21.
Miller
W. J.
,
Gebhart
B.
and
Wright
N. T.
,
1990
,
Effects of boiling history on a microconfigured surface in a dielectric liquid
,
International Communications in Heat and Mass Transfer
,
17
,
389
398
.
22.
Nowell
R. M.
,
Bhavnani
S. H.
and
Jaeger
R. C.
,
1995
,
Effect of channel width on pool boiling from a microconfigured heat sink
,
IEEE Transactions on Components, Packaging and Manufacturing Technology-Part A
, Vol.
18
, No.
3
,
534
539
.
23.
Rainey
K. N.
,
You
S. M.
and
Lee
S.
,
2003
,
Effect of pressure, subcooling and dissolved gas on pool boiling heat transfer from microporous surfaces in FC-72
,
Journal of Heat Transfer
,
125
,
75
83
.
24.
Ramaswamy
C.
,
Joshi
Y.
,
Nakayama
W.
and
Johnson
W. B.
,
2003
,
Effects of varying geometrical parameters on boiling from microfabricated enhanced structures
,
Journal of Heat Transfer
,
125
,
103
109
.
25.
Van Stralen
S. J. D.
,
1956
,
Heat transfer to boiling binary liquid mixtures at atmospheric and subatmospheric pressures
,
Chemical Engineering Science
,
5
,
290
296
.
26.
Ponter
A. B.
and
Haigh
C. P.
,
1969
,
The boiling crisis in saturated and subcooled pool boiling at reduced pressures
,
International Journal of Heat and Mass Transfer
,
12
,
429
437
.
27.
Miyauchi
T.
and
Yokura
M.
,
1972
,
The mechanism of nucleate boiling heat transfer
,
Heat Transfer - Japanese Research
, vol.
1
, No.
2
,
109
118
.
28.
Van Stralen
S. J. D.
,
Cole
R.
,
Sluyter
W. M.
and
Sohal
M. S.
,
1975
,
Bubble growth rates in nucleate boiling of water at subatmospheric pressures
,
International Journal of Heat and Mass Transfer
,
18
,
655
669
.
29.
Joudi
K. A.
and
James
D. D.
,
1977
,
Incipient boiling characteristics at atmospheric and subatmospheric pressures
,
Journal of Heat Transfer
,
99
,
398
403
.
30.
Fath
H. S.
and
Judd
R. L.
,
1978
,
Influence of system pressure on microlayer evaporation heat transfer
,
Journal of Heat Transfer
,
100
,
49
55
31.
Tewari
P. K.
,
Verma
R. K.
,
Ramani
M. P. S.
,
Chatterjee
A.
and
Mahajan
S. P.
,
1989
,
Nucleate boiling in a thin film on a horizontal tube at atmospheric and subatmospheric pressures
,
International Journal of Heat and Mass Transfer
,
32
(
4)
,
723
728
.
32.
McGillis, W. R., Carey, V. P., Fitch, J. S. and Hamburgen, W. R., 1991, Pool boiling enhancement techniques for water at low pressure, Proceedings of the Seventh IEEE SEMITHERM Symposium, 64–72.
33.
Launay, S., Federov, A., Joshi, Y., Cao, A. and Ajayan, P. M., 2004, Hybrid micro-nano structured thermal interfaces for pool boiling heat transfer enhancement, Proceedings of THERMINIC 2004, Sophia Antipolis, Cote d’Azur, France, Sep 29-Oct 1, 2004, 299–304.
34.
Latsch, K., Morell, F. and Rampf, H., 1978, Subcooled forced convection boiling heat transfer at subatmospheric pressure, Proceedings of the Sixth International Heat Transfer Conference, 287–292.
35.
Gorodov
A. K.
,
Kaban’kov
O. N.
,
Komov
A. T.
and
Yagov
V. V.
,
1979
,
Critical boiling heat fluxes to liquids at subatmospheric pressures
,
Heat Transfer - Soviet Research
,
11
(
3)
, May-June,
53
61
.
36.
You, S. M., Simon, T. W. and Bar-Cohen, A., 1990, Experiments on boiling incipience with a highly-wetting dielectric fluid: Effects of pressure, sub-cooling and dissolved gas content, Proceedings of the International Heat Transfer Conference, Hemisphere, New York, 337–342.
37.
Pal, A. and Joshi, Y., 2006, Boiling at sub-atmospheric conditions with enhanced structures, Proceedings of Itherm 2006, San Diego, USA, May 30-June 2, 2006.
38.
Ramaswamy, C., 1999, A compact two-phase thermosyphon employing microfabricated boiling enhancement structures, Ph.D. Dissertation, University of Maryland, College Park, USA.
This content is only available via PDF.
You do not currently have access to this content.