Supercritical fluid based heat transfer loop (NCL) has become a hot topic in energy conversion systems. In such systems, supercritical natural convection stability and heat transfer conditions are crucial for design and safe operation. In the present study, numerical simulations were performed to investigate the influences of heater orientations on the performance of supercritical CO2 based circulation loops. The numerical model is based on Navier-Stokes equations with supercritical turbulence effects considered. It is found that the heat source location has significant influence on the flow pattern and system heat transfer. Vertical heating cases are found stable in a wide range of heat flux conditions due to the changes of buoyancy force torques across the NCLs, while horizontal heating cases show transition heat flux and oscillations are still seen. However, the influence of heat source location is less significant on the heat transfer characteristics. The effect of cooler heat transfer is found of special importance for the heat transfer and system stability behaviors. The NCL flow and heat transfer correlations are also compared in this study, and it is recommended that more numerical and experimental studies be made in the future.

References

References
1.
Nayak
,
A. K.
,
Vijayan
,
P. K.
,
Saha
,
D.
,
Venkat
,
R. V.
, and
Aritomi
,
M.
,
2000
, “
Analytical Study of Nuclear-Coupled Density-Wave Instability in a Natural Circulation Pressure Tube Type Boiling Water Reactor
,”
Nucl. Eng. Des.
,
195
, pp.
27
44
.10.1016/S0029-5493(99)00202-2
2.
Kreitlow
,
D. B.
, and
Reistad
,
G. M.
,
1978
, “
Thermosyphon Models for Downhole Heat Exchanger Application in Shallow Geothermal Systems
,”
ASME J. Heat Transfer
,
100
, pp.
713
719
.10.1115/1.3450883
3.
Shitzer
,
A.
, and
Kalomonviz
,
D.
,
1978
, “
Experiments With a Flat Plate Solar Water Heating System in Thermo Symphonic Flow
,”
Sol. Energy
,
22
, pp.
27
35
.10.1016/0038-092X(79)90056-2
4.
Metrol
,
A.
, and
Greif
,
R.
,
1985
, “
A Review of Natural Circulation Loops
,”
Natural Convection: Fundamentals and Applications
,
S.
Kakac
,
W.
Aung
, and
R.
Viskanta
, eds.,
Hemisphere
,
New York
, pp.
1033
1071
.
5.
Hejzlar
,
P.
,
Pope
,
M. J.
, and
Williams
,
W. C.
,
2005
, “
Gas Cooled Fast Reactor for Generation IV Service
,”
Prog. Nucl. Energy
,
47
, pp.
271
282
.10.1016/j.pnucene.2005.05.077
6.
Chatoorgoon
,
V.
,
Voodi
,
A.
, and
Fraser
,
D.
,
2005
, “
The Stability Boundary for Supercritical Flow in Natural Convection Loops Part I: H2O Studies
,”
Nucl. Eng. Des.
,
235
, pp.
2570
2580
.10.1016/j.nucengdes.2005.06.003
7.
Chatoorgoon
,
V.
,
Voodi
,
A.
, and
Upadhye
,
P.
,
2005
, “
The Stability Boundary for Supercritical Flow in Natural-Convection Loops Part II: CO2 and H2
,”
Nucl. Eng. Des.
,
235
, pp.
2581
2593
.10.1016/j.nucengdes.2005.06.004
8.
NIST Standard Reference Database-REFPROP, Version 8.0
,
2006
.
9.
Dimmick
,
G. R.
,
Chatoorgon
,
V.
,
Khartabil
,
H. F.
, and
Duffey
,
R. B.
,
2002
, “
Natural-Convection Studies for Advanced CANDU Reactor Concepts
,”
Nucl. Eng. Des.
,
215
, pp.
27
38
.10.1016/S0029-5493(02)00039-0
10.
Moisseytsev
,
A.
, and
Sienicki
,
J. J.
,
2008
, “
Transient Accident Analysis of a Supercritical Carbon Dioxide Brayton Cycle Energy Converter Coupled to an Autonomous Lead-Cooled Fast Reactor
,”
Nucl. Eng. Des.
,
238
, pp.
2094
2105
.10.1016/j.nucengdes.2007.11.012
11.
Swapnalee
,
B. T.
, and
Vijayan
,
P. K.
,
2011
, “
A Generalized Flow Equation for Single-Phase Natural Circulation Loops Obeying Multiple Friction Laws
,”
Int. J. Heat Mass Transfer
,
54
, pp.
2618
2619
.10.1016/j.ijheatmasstransfer.2011.01.023
12.
Swapnalee
,
B. T.
,
Vijayan
,
P. K.
,
Sharma
,
M.
, and
Pilkhwal
,
D. S.
,
2012
, “
Steady State Flow and Static Instability of Supercritical Natural Circulation Loops
,”
Nucl. Eng. Des.
,
245
, pp.
99
112
.10.1016/j.nucengdes.2012.01.002
13.
Chen
,
L.
,
Zhang
,
X. R.
,
Yamaguchi
,
H.
, and
Liu
,
Z. S.
(Simon),
2010
, “
Effect of Heat Transfer on the Instabilities and Transitions of Supercritical CO2 Flow in a Natural Circulation Loop
,”
Int. J. Heat Mass Transfer
,
53
, pp.
4101
4111
.10.1016/j.ijheatmasstransfer.2010.05.030
14.
Vijayan
,
P. K.
,
Austregesilo
,
H.
, and
Teschendorff
,
V.
,
1995
, “
Simulation of the Unstable Oscillatory Behavior of Single-Phase Circulation With Repetitive Flow Reversals in a Rectangular Loop Using the Computer Code ATHLET
,”
Nucl. Eng. Des.
,
155
, pp.
623
641
.10.1016/0029-5493(94)00972-2
15.
Welander
,
P.
,
1967
,
On the Oscillatory Instability of a Differentially Heated Fluid Loop
,”
J. Fluid Mech.
,
29
, pp.
17
30
.10.1017/S0022112067000606
16.
Yoshikawa
,
S.
,
Smith
, Jr.,
R. L.
,
Inomata
,
H.
,
Matsumura
,
Y.
, and
Arai
,
K.
,
2005
, “
Performance of a Natural Convection Circulation System for Supercritical Fluids
,”
J. Supercrit. Fluids
,
36
, pp.
70
80
.10.1016/j.supflu.2005.02.007
17.
Jain
,
P. K.
, and
Rizwan-uddin
,
2008
, “
Numerical Analysis of Supercritical Flow Instabilities in a Natural Circulation Loop
,”
Nucl. Eng. Des.
,
238
, pp.
1947
1957
.10.1016/j.nucengdes.2007.10.034
18.
Kumar
,
K. K.
, and
Gopal
,
M. R.
,
2008
, “
Steady-State Analysis of CO2 Based Natural Circulation Loops With End Heat Exchangers
,”
Appl. Therm. Eng.
,
29
, pp.
1893
1903
.10.1016/j.applthermaleng.2008.08.002
19.
Kumar
,
K. K.
, and
Gopal
,
M. R.
,
2011
, “
Experimental Studies on CO2 Based Single and Two-Phase Natural Circulation Loops
,”
Appl. Therm. Eng.
,
31
, pp,
3437
3443
.10.1016/j.applthermaleng.2011.06.029
20.
Chen
,
L.
, and
Zhang
,
X. R.
,
2011
, “
Simulation of Heat Transfer and System Behavior in a Supercritical CO2 Based Thermosyphon: Effect of Pipe Diameter
,”
ASME J. Heat Transfer
,
133
, pp.
2505
2513
.10.1115/1.4004434
21.
Zhang
,
X. R.
,
Chen
,
L.
, and
Yamaguchi
,
H.
,
2010
, “
Natural Convective Flow and Heat Transfer of Supercritical CO2 in a Rectangular Circulation Loop
,”
Int. J. Heat Mass Transfer
,
53
, pp.
4112
4122
.10.1016/j.ijheatmasstransfer.2010.05.031
22.
Chen
,
L.
,
Zhang
,
X. R.
,
Cao
,
S.
, and
Bai
,
H.
,
2012
, “
Study of Trans-Critical CO2 Natural Convection Flow With Unsteady Heat Input and Its Implications on System Control
,”
Int. J. Heat Mass Transfer
,
55
, pp.
7119
7132
.10.1016/j.ijheatmasstransfer.2012.07.027
23.
Chen
,
L.
,
Deng
,
B. L.
,
Jiang
,
B.
, and
Zhang
,
X. R.
,
2013
, “
Thermal and Hydrodynamic Characteristics of Supercritical CO2 Natural Circulation in Closed Loops
,”
Nucl. Eng. Des.
,
257
, pp.
21
30
.10.1016/j.nucengdes.2013.01.016
24.
Chen
,
L.
,
Deng
,
B. L.
, and
Zhang
,
X. R.
,
2013
, “
Experimental Study of Trans-Critical and Supercritical CO2 Natural Circulation Flow in a Closed Loop
,”
Appl. Therm. Eng.
,
59
, pp.
1
13
.10.1016/j.applthermaleng.2013.05.017
25.
Chen
,
L.
,
Deng
,
B. L.
, and
Zhang
,
X. R.
,
2013
, “
Experimental Investigation of CO2 Thermosyphon Flow and Heat Transfer in the Supercritical Region
,”
Int. J. Heat Mass Transfer
,
64
, pp.
202
211
.10.1016/j.ijheatmasstransfer.2013.03.077
26.
Yamaguchi
,
H.
,
Sawada
,
N.
,
Suzuki
,
H.
,
Ueda
,
H.
, and
Zhang
,
X. R.
,
2010
, “
Preliminary Study on a Solar Water Heater Using Supercritical Carbon Dioxide as Working Fluid
,”
ASME J. Sol. Energy Eng.
,
132
, pp.
101
106
.10.1115/1.4000350
27.
Zhang
,
X. R.
, and
Yamaguchi
,
H.
,
2007
, “
Forced Convection Heat Transfer of Supercritical Carbon Dioxide in a Horizontal Circular Tube
,”
J. Supercrit. Fluids
,
41
, pp.
412
420
.10.1016/j.supflu.2006.11.003
28.
He
,
S.
,
Jiang
,
P. X.
,
Xu
,
Y. J.
,
Shi
,
R. F.
, and
Jackson
,
J. D.
,
2005
, “
A Computational Study of Convection Heat Transfer to CO2 at Supercritical Pressures in a Vertical Mini Tube
,”
Int. J. Therm. Sci.
,
44
, pp.
512
530
.10.1016/j.ijthermalsci.2004.11.003
29.
Bernier
,
M. A.
, and
Baliga
,
B. R.
,
1992
, “
A 1-D/2-D Model and Experimental Results for a Closed-Loop Thermosyphon With Vertical Heat Transfer Sections
,”
Int. J. Heat Mass Transfer
,
35
, pp.
2969
2982
.10.1016/0017-9310(92)90317-L
30.
Vijayan
,
P. K.
,
Bhojwani
,
V. K.
,
Bade
,
M. H.
,
Sharma
,
M.
,
Nayak
,
A. K.
,
Saha
,
D.
, and
Sinha
,
R. K.
,
2001
, “
Investigations on the Effect of Heater and Cooler Orientation on the Steady State, Transient and Stability Behavior of Single-Phase Natural Circulation in a Rectangular Loop
,” BARC/2001/E/034, Bhabha Atomic Research Centre, Mumbai, India.
31.
Vijayan
,
P. K.
,
Sharma
,
M.
, and
Saha
,
D.
,
2007
Steady-State and Stability Characteristics of a Single-Phase Natural Circulation in a Rectangular Loop With Different Heater and Cooler Orientations
,”
Exp. Therm. Fluid Sci.
,
31
, pp.
925
945
.10.1016/j.expthermflusci.2006.10.003
32.
Yang
,
J.
,
Oka
,
Y.
,
Ishiwatari
,
Y.
,
Liu
,
J.
, and
Yoo
,
J.
,
2007
, “
Numerical Investigation of Heat Transfer in Upward Flow of Supercritical Water in Circular Tubes and Tight Fuel Rod Bundles
,”
Nucl. Eng. Des.
,
237
, pp.
420
430
.10.1016/j.nucengdes.2006.08.003
33.
Lisboa
,
P. F.
,
Fernandes
,
J.
,
Simoes
,
P. C.
,
Mota
,
J. P. B.
, and
Saatdjian
,
E.
,
2010
, “
Computational Fluid Dynamics Study of a Kenics Static Mixer as a Heat Exchanger for Supercritical Carbon Dioxide
,”
J. Supercrit. Fluids
,
55
, pp.
107
115
.10.1016/j.supflu.2010.08.005
34.
Shang
,
Z.
, and
Chen
,
S.
,
2011
, “
Numerical Investigation of Diameter Effect on Heat Transfer of Supercritical Water Flows in Horizontal Round Tubes
,”
Appl. Therm. Eng.
,
31
(
4
), pp.
573
581
.10.1016/j.applthermaleng.2010.10.020
35.
Shang
,
Z.
,
2009
, “
CFD Investigation of Vertical Rod Bundles of Supercritical Water-Cooled Nuclear Reactor
,”
Nucl. Eng. Des.
,
232
(
2
), pp.
157
163
.10.1016/j.nucengdes.2004.06.008
36.
Xiong
,
Q.
,
Li
,
B.
,
Wang
,
X.
,
Wang
,
L.
, and
Ge
,
W.
,
2012
, “
Efficient 3D DNS of Gas–Solid Flows on Fermi GPGPU
,”
Comput. Fluids
,
70
, pp.
86
94
10.1016/j.compfluid.2012.08.026
37.
Xiong
,
Q.
,
Li
,
B.
,
Chen
,
F.
,
Ma
,
J.
,
Ge
,
W.
, and
Li
,
J.
,
2010
, “
Direct Numerical Simulation of Sub-Grid Structures in Gas-Solid Flow-GPU Implementation of Macro-Scale Pseudo-Particle Modeling
,”
Chem. Eng. Sci.
,
65
, pp.
5356
5365
.10.1016/j.ces.2010.06.035
38.
Issa
,
R. I.
,
1986
, “
Solution of the Implicit Discretized Fluid Flow Equations by Operator Splitting
,”
J. Comput. Phys.
,
62
, pp.
40
65
.10.1016/0021-9991(86)90099-9
39.
Ambrosini
,
W.
,
2007
, “
On the Analogies in the Dynamic Behavior of Heated Channels With Boiling and Supercritical Fluids
,”
Nucl. Eng. Des.
,
237
, pp.
1164
1174
.10.1016/j.nucengdes.2007.01.006
40.
Vijayan
,
P. K.
,
Bade
,
M. H.
,
Saha
D.
,
Sinha
R. K.
, and
Raj V.
Venkat
,
2004
, “
A Generalized Flow Correlation for Single-Phase Natural Circulation Loops
,”
Proceedings of the 17th National and 6th ISHMT/ASME Heat and Mass Transfer Conference
,
Kalpakkam, India
, January, HMT-2004-C022.
41.
Misale
,
M.
,
Garibaldi
,
P.
,
Passos
,
J. C.
, and
Bitencourt Ghisi
,
G.
,
2007
, “
Experiments in a Single-Phase Natural Circulation Mini-Loop
,”
Exp. Therm. Fluid Sci.
,
31
, pp.
1111
1120
.10.1016/j.expthermflusci.2006.11.004
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