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