A hydrogen-producing solar reactor was experimentally tested to study the cyclone flow dynamics of the gas–particle two-phase phenomenon. Two-dimensional particle image velocimetry (PIV) was used to observe the flow and to quantify the vortex formation inside the solar reactor. The vortex flow structure in the reactor was reconstructed by capturing images from orientations perpendicular and parallel to the geometrical axis of the reactor, respectively. The experimental results showed that the tangential components of the fluid velocity formed a Rankine-vortex profile. The free vortex portions of the Rankine profile were synchronized and independent of the axial position. The axial components showed a vortex funnel of higher speed fluid supplied by a reversing secondary flow. According to the inlet channel design, the geometry dominates the flow dynamics. A stable processing vortex line was observed. As the vortex flow evolves toward the exit, the vortex funnel expands radially with decreasing tangential velocity magnitude peak as a result of the vortex stretching. An optimal residence time of the flow was found by changing the cyclone flow inlet conditions. The swirl number versus the main flow rate change was obtained. Upon completion of the experimental studies, a thorough numerical analysis was conducted to model the flow dynamics inside the solar reactor and to verify the results by comparison to the experimental results. Three turbulence models including the standard k–ϵ, k–ϵ renormalization groups (RNG), and Reynolds stress transport models were used. Computational fluid dynamics (CFD) simulations were coupled with heat transfer analysis via discrete ordinate (DO) model. Particle tracing in Lagrange frame was applied to simulate the particle trajectory. A comparison between the turbulence modeling results for the room temperature and high temperature cases, as well as the experimental results for room temperature cases is presented.

References

References
1.
Rodat
,
S.
,
Abanades
,
S.
,
Sans
,
J. L.
, and
Flamant
,
G.
,
2010
, “
A Pilot-Scale Solar Reactor for the Production of Hydrogen and Carbon Black From Methane Splitting
,”
Int. J. Hydrogen Energy
,
35
(
15
), pp.
7748
7758
.10.1016/j.ijhydene.2010.05.057
2.
Abanades
,
A.
,
Rubbia
,
C.
, and
Salmieri
,
D.
,
2012
, “
Technological Challenges for Industrial Development of Hydrogen Based Methane Cracking
,”
Energy
,
46
(
1
), pp.
359
363
.10.1016/j.energy.2012.08.015
3.
Shilapuram
,
V.
,
Devanuri
,
J. K.
, and
Ozalp
,
N.
,
2010
, “
Residence Time Distribution and Flow Field Study of Aero-Shielded Solar Cyclone Reactor for Emission-Free Generation of Hydrogen
,”
Int. J. Hydrogen Energy
,
36
(
21
), pp.
13488
13500
.10.1016/j.ijhydene.2011.08.035
4.
Rodat
,
S.
,
Abanades
,
S.
, and
Flamant
,
G.
,
2010
, “
Experimental Evaluation of Indirect Heating Tubular Reactors for Solar Methane Pyrolysis
,”
Int. J. Chem. React. Eng.
,
8
(
1
), p.
A25
.10.2202/1542-6580.2084
5.
Hirsch
,
D.
, and
Steinfeld
,
A.
,
2004
, “
Solar Hydrogen Production by Thermal Decomposition of Natural Gas Using a Vortex-Flow Reactor
,”
Int. J. Hydrogen Energy
,
29
(
1
), pp.
47
55
.10.1016/S0360-3199(03)00048-X
6.
Ozalp
,
N.
,
Chien
,
M.
, and
Morrison
,
G.
,
2013
, “
Computational Fluid Dynamics and Particle Image Velocimetry Characterization of a Solar Cyclone Reactor
,”
ASME J. Sol. Energy Eng.
,
135
(
3
), p.
031003
.10.1115/1.4023183
7.
Devanuri
,
J.
, and
Ozalp
,
N.
,
2013
, “
Numerical Investigation of Particle Deposition Inside Aero-Shielded Solar Cyclone Reactor: A Promising Solution for Reactor Clogging
,”
Int. J. Heat Fluid Flow
,
40
, pp.
198
209
.10.1016/j.ijheatfluidflow.2012.12.004
8.
Szekely
,
J.
, and
Carr
,
R.
,
1966
, “
Heat Transfer in a Cyclone
,”
Chem. Eng. Sci.
,
21
(
12
), pp.
1119
1132
.10.1016/0009-2509(66)85033-9
9.
Ozalp
,
N.
, and
Devanuri
,
J.
,
2010
, “
Numerical Study on the Thermal Interaction of Gas-Particle Transport for a Vortex Flow Solar Reactor
,”
ASME
Paper No. ES2010-90325.10.1115/ES2010-90325
10.
Trommer
,
D.
,
Hirsch
,
D.
, and
Steinfeld
,
A.
,
2004
, “
Kinetic Investigation of the Thermal Decomposition of CH4 by Direct Irradiation of a Vortex-Flow Laden With Carbon Particles
,”
Int. J. Hydrogen Energy
,
29
(
6
), pp.
627
633
.10.1016/j.ijhydene.2003.07.001
11.
Kogan
,
A.
, and
Kogan
,
M.
,
2002
, “
The Tornado Flow Configuration: An Effective Method for Screening of a Solar Reactor Window
,”
ASME J. Sol. Energy Eng.
,
124
(
3
), pp.
206
214
.10.1115/1.1487882
12.
Chen
,
H.
,
Chen
,
Y.
,
Hsieh
,
H. T.
, and
Siegel
,
N.
,
2007
, “
Computational Fluid Dynamics Modeling of Gas-Particle Flow Within a Solid-Particle Solar Receiver
,”
ASME J. Sol. Energy Eng.
,
129
(
2
), pp.
160
170
.10.1115/1.2716418
13.
Clifford
,
K.
,
Ho
,
S.
,
Khalsa
,
S.
, and
Siegel
,
N.
,
2009
, “
Modeling on Sun-Tests of a Prototype Solid Particle Receiver for Concentrating Solar Power Processes and Storage
,”
ES2009, Energy Sustainability
,
San Francisco, CA
, July 19–23, Paper No. ES2009-90035, pp.
543
550
.
14.
Wu
,
Z.
,
Caliot
,
C.
,
Flamant
,
G.
, and
Wang
,
Z.
,
2011
, “
Coupled Radiation and Flow Modeling in Ceramic Foam Volumetric Solar Air Receivers
,”
Sol. Energy
,
85
(
9
), pp.
2374
2385
.10.1016/j.solener.2011.06.030
15.
Ozalp
,
N.
,
Chien
,
M.
, and
Morrison
,
G. L.
,
2012
, “
Experimental Evaluation of a Solar Cyclone Reactor Via Particle Image Velocimetry
,”
ASME
Paper No. HT2012-58149.10.1115/HT2012-58149
16.
Hirsch
,
D.
, and
Steinfeld
,
A.
,
2004
, “
Radiative Transfer in a Solar Chemical Reactor for the Co-Production of Hydrogen and Carbon by Thermal Decomposition of Methane
,”
Chem. Eng. Sci.
,
59
(
24
), pp.
5771
5778
.10.1016/j.ces.2004.06.022
17.
Jones
,
W. P.
, and
Launder
,
B. E.
,
1972
, “
The Prediction of Laminarization With a Two-Equation Model of Turbulence
,”
Int. J. Heat Mass Transfer
,
15
(
2
), pp.
301
314
.10.1016/0017-9310(72)90076-2
18.
Yakhot
,
V.
,
Orszag
,
S. A.
,
Thangam
,
S.
,
Gatski
,
T. B.
, and
Speziale
,
C. G.
,
1992
, “
Development of Turbulence Models for Shear Flows by a Double Expansion Technique
,”
Phys. Fluids A
,
4
(
7
), pp.
1510
1520
.10.1063/1.858424
19.
Ozalp
,
N.
, and
Jayakrishna
,
D.
,
2010
, “
CFD Analysis on the Influence of Helical Carving in a Vortex Flow Solar Reactor
,”
Int. J. Hydrogen Energy
,
35
(
12
), pp.
6248
6260
.10.1016/j.ijhydene.2010.03.100
20.
Bohren
,
C. F.
, and
Huffman
,
D. K.
,
1983
,
Absorption and Scattering of Light by Small Particles
,
Wiley
,
New York
.
21.
Dalzell
,
W. H.
, and
Sarofim
,
A. F.
,
1969
, “
Optical Constants of Soot and Their Application to Heat Flux Calculations
,”
ASME J. Heat Transfer
,
91
(
1
), pp.
100
104
.10.1115/1.3580063
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