In this paper, the flow patterns during water flow boiling instability in pin-fin microchannels were experimentally studied. Three types of pin-fin arrays (in-line/circular pin-fins, staggered/circular pin-fins, and staggered/square pin-fins) were used in the study. The flow instability started to occur as the outlet water reached the saturation temperature. Before the unstable boiling, a wider range of stable boiling existed in the pin-fin microchannels compared to that in the plain microchannels. Two flow instability modes for the temperature and pressure oscillations, which were long-period/large-amplitude mode and short-period/small-amplitude mode, were identified. The temperature variation during the oscillation period of the long-period/large-amplitude mode can be divided into two stages: increasing stage and decreasing stage. In the increasing stage, bubbly flow, vapor-slug flow, stratified flow, and wispy flow occurred sequentially with time for the in-line pin-fin microchannels; liquid single-phase flow, aforementioned four kinds of two-phase flow patterns, and vapor single-phase flow occurred sequentially with time for the staggered pin-fin microchannel. The flow pattern transitions in the decreasing stage were the inverse of those in the increasing stage for both in-line and staggered pin-fin microchannels. For the short-period/small-amplitude oscillation mode, only the wispy flow occurred. With the increase of heat flux, the wispy flow and the vapor single-phase flow occupied more and more time ratio during an oscillation period in the in-line and staggered pin-fin microchannels.

References

References
1.
Garimella
,
S. V.
, and
Sobhan
,
C. B.
,
2003
, “
Transport in Microchannels—A Critical Review
,”
Annu. Rev. Heat Transfer
,
13
, pp.
1
50
.
2.
Cheng
,
P.
, and
Wu
,
H. Y.
,
2006
, “
Mesoscale and Microscale Phase-Change Heat Transfer
,”
Adv. Heat Transfer
,
39
, pp.
461
563
.
3.
Kandlikar
,
S. G.
, and
Grande
,
W. J.
,
2004
, “
Evaluation of Single Phase Flow in Microchannels for High Heat Flux Chip Cooling—Thermo Hydraulic Performance Enhancement and Fabrication Technology
,”
Heat Transfer Eng.
,
25
(8), pp.
5
16
.
4.
Kandlikar
,
S. G.
,
Colin
,
S.
,
Peles
,
Y.
,
Garimella
,
S.
,
Pease
,
R. F.
,
Brandner
,
J. J.
, and
Tuckerman
,
D. B.
,
2013
, “
Heat Transfer in Microchannels—2012 Status and Research Needs
,”
ASME J. Heat Transfer
,
135
(9), p.
091001
.
5.
Peles
,
Y.
,
Koşar
,
A.
,
Mishra
,
C.
,
Kuo
,
C.
, and
Schneider
,
B.
,
2005
, “
Forced Convective Heat Transfer Across a Pin Fin Micro Heat Sink
,”
Int. J. Heat Mass Transfer
,
48
(17), pp.
3615
3627
.
6.
Prasher
,
R. S.
,
Dirner
,
J.
,
Chang
,
J.
,
Myers
,
A.
,
Chau
,
D.
,
He
,
D. M.
, and
Prstic
,
S.
,
2007
, “
Nusselt Number and Friction Factor of Staggered Arrays of Low Aspect Ratio Micro Pin-Fins Under Cross Flow for Water as Fluid
,”
ASME J. Heat Transfer
,
129
(2), pp.
141
153
.
7.
Qu
,
W.
, and
Siu-Ho
,
A.
,
2008
, “
Liquid Single-Phase Flow in an Array of Micro-Pin-Fins—Part I: Heat Transfer Characteristics
,”
ASME J. Heat Transfer
,
130
(12), p.
122402
.
8.
Roth
,
R.
,
Lenk
,
G.
,
Cobry
,
K.
, and
Woias
,
P.
,
2013
, “
Heat Transfer in Freestanding Microchannels With In-Line and Staggered Pin Fin Structures With Clearance
,”
Int. J. Heat Mass Transfer
,
67
, pp.
1
15
.
9.
Renfer
,
A.
,
Tiwari
,
M. K.
,
Tiwari
,
R.
,
Alfieri
,
F.
,
Brunschwiler
,
T.
,
Michel
,
B.
, and
Poulikakos
,
D.
,
2013
, “
Microvortex-Enhanced Heat Transfer in 3D-Integrated Liquid Cooling of Electronic Chip Stacks
,”
Int. J. Heat Mass Transfer
,
65
, pp.
33
43
.
10.
Mei
,
D.
,
Lou
,
X.
,
Qian
,
M.
,
Yao
,
Z.
,
Liang
,
L.
, and
Chen
,
Z.
,
2014
, “
Effect of Tip Clearance on the Heat Transfer and Pressure Drop Performance in the Micro-Reactor With Micro-Pin-Fin Arrays at Low Reynolds Number
,”
Int. J. Heat Mass Transfer
,
70
, pp.
709
718
.
11.
Koşar
,
A.
, and
Peles
,
Y.
,
2006
, “
Convective Flow of Refrigerant (R-123) Across a Bank of Micro Pin Fins
,”
Int. J. Heat Mass Transfer
,
49
(17–18), pp.
3142
3155
.
12.
Lie
,
Y. M.
,
Ke
,
J. H.
,
Chang
,
W. R.
,
Cheng
,
T. C.
, and
Lin
,
T. F.
,
2007
, “
Saturated Flow Boiling Heat Transfer and Associated Bubble Characteristics of FC-72 on a Heated Micro-Pin-Finned Silicon Chip
,”
Int. J. Heat Mass Transfer
,
50
(19–20), pp.
3862
3876
.
13.
Qu
,
W.
, and
Siu-Ho
,
A.
,
2009
, “
Experimental Study of Saturated Flow Boiling Heat Transfer in an Array of Staggered Micro-Pin-Fins
,”
Int. J. Heat Mass Transfer
,
52
(7–8), pp.
1853
1863
.
14.
Chang
,
W. R.
,
Chen
,
C. A.
,
Ke
,
J. H.
, and
Lin
,
T. F.
,
2010
, “
Subcooled Flow Boiling Heat Transfer and Associated Bubble Characteristics of FC-72 on a Heated Micro-Pin-Finned Silicon Chip
,”
Int. J. Heat Mass Transfer
,
53
(23–24), pp.
5605
5621
.
15.
Mcneil
,
D. A.
,
Raeisi
,
A. H.
,
Kew
,
P. A.
, and
Hamed
,
R. S.
,
2014
, “
An Investigation Into Flow Boiling Heat Transfer and Pressure Drop in a Pin-Finned Heat Sink
,”
Int. J. Multiphase Flow
,
67
(Suppl.), pp.
65
84
.
16.
Koşar
,
A.
, and
Peles
,
Y.
,
2007
, “
Boiling Heat Transfer in a Hydrofoil-Based Micro Pin Fin Heat Sink
,”
Int. J. Heat Mass Transfer
,
50
(5–6), pp.
1018
1034
.
17.
Krishnamurthy
,
S.
, and
Peles
,
Y.
,
2008
, “
Flow Boiling of Water in a Circular Staggered Micro-Pin Fin Heat Sink
,”
Int. J. Heat Mass Transfer
,
51
(5–6), pp.
1349
1364
.
18.
Krishnamurthy
,
S.
, and
Peles
,
Y.
,
2010
, “
Flow Boiling Heat Transfer on Micro Pin Fins Entrenched in a Microchannel
,”
ASME J. Heat Transfer
,
132
(4), p.
041007
.
19.
Koşar
,
A.
,
Özdemir
,
M. R.
, and
Keskinoz
,
M.
,
2010
, “
Pressure Drop Across Micro-Pin Heat Sinks Under Unstable Boiling Conditions
,”
Int. J. Therm. Sci.
,
49
(7), pp.
1253
1263
.
20.
Lyu
,
Z.
,
Xu
,
J.
,
Yu
,
X.
,
Jin
,
W.
, and
Zhang
,
W.
,
2015
, “
Wavelet Decomposition Method Decoupled Boiling/Evaporation Oscillation Mechanisms Over Two to Three Timescales: A Study for a Microchannel With Pin Fin Structure
,”
Int. J. Multiphase Flow
,
72
, pp.
53
72
.
21.
Wang
,
G.
,
Cheng
,
P.
, and
Bergles
,
A. E.
,
2008
, “
Effects of Inlet/Outlet Configurations on Flow Boiling Instability in Parallel Microchannels
,”
Int. J. Heat Mass Transfer
,
51
(
9
), pp.
2267
2281
.
22.
Bogojevic
,
D.
,
Sefiane
,
K.
,
Walton
,
A. J.
,
Lin
,
H.
, and
Cummins
,
G.
,
2009
, “
Two-Phase Flow Instabilities in a Silicon Microchannels Heat Sink
,”
Int. J. Heat Fluid Flow
,
30
(
5
), pp.
854
867
.
23.
Kandlikar
,
S. G.
,
Kuan
,
W. K.
,
Willistein
,
D. A.
, and
Borrelli
,
J.
,
2006
, “
Stabilization of Flow Boiling in Microchannels Using Pressure Drop Elements and Fabricated Nucleation Sites
,”
ASME J. Heat Transfer
,
128
(
4
), pp.
389
396
.
24.
Wu
,
H. Y.
,
Cheng
,
P.
, and
Wang
,
H.
,
2006
, “
Pressure Drop and Flow Boiling Instabilities in Silicon Microchannel Heat Sinks
,”
J. Micromech. Microeng.
,
16
(
10
), pp.
2138
2146
.
25.
Kuo
,
C. J.
, and
Peles
,
Y.
,
2008
, “
Flow Boiling Instabilities in Microchannels and Means for Mitigation by Reentrant Cavities
,”
ASME J. Heat Transfer
,
130
(7), p.
072402
.
26.
Wu
,
H. Y.
, and
Cheng
,
P.
,
2004
, “
Boiling Instability in Parallel Silicon Microchannels at Different Heat Flux
,”
Int. J. Heat Mass Transfer
,
47
(17–18), pp.
3631
3641
.
27.
Xu
,
J.
,
Zhou
,
J.
, and
Gan
,
Y.
,
2005
, “
Static and Dynamic Flow Instability of a Parallel Microchannel Heat Sink at High Heat Fluxes
,”
Energy Convers. Manage.
,
46
(2), pp.
313
334
.
28.
Wang
,
G.
,
Cheng
,
P.
, and
Wu
,
H.
,
2007
, “
Unstable and Stable Flow Boiling in Parallel Microchannels and in a Single Microchannel
,”
Int. J. Heat Mass Transfer
,
50
(21–22), pp.
4297
4310
.
29.
Prajapati
,
Y. K.
,
Pathak
,
M.
, and
Khan
,
K. M.
,
2015
, “
A Comparative Study of Flow Boiling Heat Transfer in Three Different Configurations of Microchannels
,”
Int. J. Heat Mass Transfer
,
85
, pp.
711
722
.
You do not currently have access to this content.