University R & D Session
KAIST Activities
Associate ProfessorDept. of Nuclear & Quantum Engineering, KAIST
Jeong IK Lee
2016. 3. 30
1
Issues Studied in KAIST Larger power system requires higher specific power
Advanced turbomachinery and heat exchanger design and analysis methodologies
New type of components or systems
Transient analysis (Startup, Shutdown, Incidents…)
Specific Technical Issues to Specific Heat Source
Critical Flow and Phase Change
Materials
2
Increasing Specific Power
3
Turbomachinery Design & Analysis
200 300 400 500 600 700 800 900 100082
82.5
83
83.5
84
84.5
85
85.5
86
86.5
Mass Flow Rate (kg/s)
Tota
l to T
otal
Effic
ienc
y (%
)rpm=3600 rpm=4500 rpm=5400 rpm=6300
rpm=7200
Turbomachinery Efficiency-Mdot Map
On-design point
KAIST_TMD- 1D Meanline Analysis -
3D CFD analysis
Internal flow analysis can be supported by 3D CFD analysis
Complementary assistance platform can be constructed from 3D model information generation
Transient analysis
Turbomachinery performance maps support transient analysis for abnormal system operation scenarios
#15
Comp
#25
#50
#200
: Fluid block
: External junction
: Boundary volume
Pipe
#20
#30#40
#10#60
#100#300
#120 #110
: Pipe wall
Pipe
Pipe
PipePipe
Cooler: CO2
: Cooling water
: Expansion valve (Globe valve)
KAIST_TMD
F1D
F3D
Jext
Bvol
<Fluid System>
W1D
W3D
<Wall System>SmHX
Pump
Comp
Turb
Valve Scon
Ccon
Fuel
Pkin
Gtab Ctl Plt
etc. etc.
( , )s sm T P AVρ=
2
2
0Vhh s +=
( , )s sT h s( , )s sP h s
V&V
-0.06 -0.04 -0.02 0 0.02 0.04 0.060
0.01
0.02
0.03
Radial distance (m)
Axi
al d
ista
nce
(m)
"Real Gas - Numerical", Impeller"Real Gas - Numerical", Diffuser"Real Gas - Exponent", Impeller"Real Gas - Exponent", Diffuser
4
Turbomachinery Design IssuesConversion method Equations
Definition based
Ideal gas based
Real gas isentropic exponent based
2
2o svh h= +
12112
o
s
Mpp
γγγ −− = +
212
1o
s
T MT
γ −= +
112
211 sn
o s
s
n Mpp
−− = +
12112
s s
so s
s
m nnn MT
T−
−= +
0 20 40 60 80 100 120 140 160 180 200-10
0
10
20
30
40
50
60
70
80
90
Tangential velocity (m/s)
Mer
idio
nal v
eloc
ity (m
/.s)
"Real Gas - Numerical", Impeller tip speed"Real Gas - Numerical", Absolute velocity"Real Gas - Numerical", Relative velocity"Real Gas - Exponent", Impeller tip speed"Real Gas - Exponent", Absolute velocity"Real Gas - Exponent", Relative velocity
5
Heat Exchanger Design & Analysis
6
New Component
KAIST – SCO2PE
A Tesla turbine will be tested in S-CO2 power cycle expander operating conditions.
The external pressure vessel allows to test in high pressure (>7.4 MPa)
Tesla turbine
Conventional Turbine Tesla turbine
Characteristics
Blade Bladeless disc
Impulse & reaction force Friction force
Well experienced, optimized Low Pressure ratio (S-CO2 cycle)
Need high quality clearance Manufacturing - easy and modularized design
No phase change allowed Robust - Two phase, Sludge flow
Maintenance Difficulties Easy maintenance
7
New System
<Conceptual figure of KAIST MMR>
<MMR core design>
<With 8 fans and generator>
8
Transient Analysis for Control
9
Transient Analysis for PredictionGAMMA+ code modification
The parallel configuration of models in the GAMMA+
Off-design performance map of SCO2PE compressor
Nodalization diagram of the SCO2PE loop for GAMMA+ code
V&V between GAMMA+ code and SCO2PE test data
Transient pressure data comparison
10
Specific Technical Issues to Sodium-cooled Fast Reactor Application
Fig. Potential Na-CO2 interaction in Printed Circuit Heat Exchanger(PCHE)
Na (~0.1MPa)
CO2 (~20MPa)
Micro-meter size crack
Ingress of high-pressure CO2& Na-CO2 interaction
TNa = 599.9 ℃Ignition caseTNa = 598.3 ℃ TNa = 585 ℃
Na-air reaction
11
Critical Flow and Phase Change
Fig. CO2 critical speed measure instrument
11
Exp_1 Exp_2 Exp_3
HighPressure
Tank
P (MPa) 10.01 13.43 20.16
T (℃) 103.3 161.5 151.2
LowPressure
Tank
P (MPa) 0.101 0.101 0.101
T (℃) 14.5 15.6 14.1
CO2 leak simulation results (T-s, h-s diagram, Mass flux of leaked CO2)
CO2 critical flow modeling process
1.0 1.5 2.0 2.5 3.00
20
40
60
80
100
120
140
160
180 Exp_1 Exp_1
Exp_3 Exp_3
Exp_2 Exp_2
Tem
pera
ture
(°C
)
Entropy (kJ/kg-K)
Low-pressure tank
High-pressure tank
0.1M
Pa
1MP
a
5MP
a
10M
Pa
15M
Pa
20M
Pa
Critical point
time
time
12
Materials Corrosion and carburization behavior
in S-CO2 environments Corrosion tests in S-CO2 environments (550-650oC, 200bar, max. 3000h) Evaluate the corrosion and carburization resistance in S-CO2 environments Materials: Fe-base austenitic alloys, Ni-base alloys, FMS (9Cr)
Long-term properties of materials after exposure to S-CO2Microstructure evolution and resulting mechanical
property (tensile test)Creep test in S-CO2 environments (550-650oC,
200bar)
Corrosion and long-term properties of diffusion-bonded PCHE materialsDevelopment of diffusion-bonding process for
PCHE-type IHXCorrosion tests and mechanical property evaluation
of diffusion bonded joints in S-CO2 environments