ANNUAL REPORT 2007UIUC, June 12, 2007
Huan Li (Ph. D. Student) &Brian G. Thomas
Department of Mechanical Science and EngineeringUniversity of Illinois at Urbana-Champaign
Temperature evolution in the spray zones:
plant measurements and CON1D prediction
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 2
Objective
• Develop accurate model of spray cooling (for use in online control, etc.)– Incorporate Leidenfrost effect into spray
cooling model
– Test the accuracy of the Goodrich pyrometers at Riverdale caster
– Compare CON1D model with measurents
• Study transient phenomena during spray water changes
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 3
Outline
• CON1D model description
• Plant measurements at Riverdale
• Comparison of original model with Riverdale measurements
• Compare improved model (with Leidenfrost) for Riverdale and Nucor cases
• Nucor experiments: transient case
• Conclusions
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 4
CON1D model
Continuous casting of steel
-ccc.me.uiuc.edu
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 5
CON1D model
Simulation domain
-K. Zheng, concontroller user’s manual -con1d8.0 user’s manual
I shape domain
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 6
Heat transfer coefficient in Spray Zones
Nozaki – A*C=0.3925, n=0.55, b=0.0075
Water Flux
Temperature of spray cooling water
Ambient Temperature
Fraction of heat extraction to rolls
CON1D model
( )1nspray water sprayh A C Q b T= ⋅ ⋅ ⋅ − ⋅
( )( )2 2_ K amb K K amb Krad spray steel s sh T T T Tσ ε= ⋅ ⋅ + +
Spray nozzle cooling
Natural convetion
Conducton to the roll
Radiation
28.7 W/m Kconvh =
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 7
CON1D model
Slab
Roll
Spraynozzle
5300
5400
5500
5600
0 1000 2000 3000 4000 5000 6000 7000
Dis
tanc
e be
low
men
iscu
s (m
m)
h (W/m^2K)
Radiation heat transfer coefficient, h_radSpray heat transfer coefficient, h_spr
Roll heat transfer coefficient, h_roll 5300
5400
5500
5600
700 800 900 1000 1100 1200 1300 1400 1500 1600
Dis
tanc
e (m
m)
Surface Temperature (°C))
Heat transfer coefficient in Spray Zones
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 8
Leidenfrost effect
VAPOR
HIGHER SURFACE TEMPERATURE
DROPLET
q y p y p p q p
NUCLEATE BOILINGBubbles form and thedroplet evaporates slowly
TRANSITION BOILINGMarked by violent sizzling. Droplet boils away explosivelyas soon as it hits the surface
FILM BOILINGThe droplet floats quietlyon a vapor cushion, and evaporates very slowly
Ts-100 (°C)
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 9
Considering Leidenfrost by h-multipliers
1050
1.0
1000900800700Temperature °C
1.62.21.21.0h-multipliers
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 10
Spray coefficient C
0.250.4zone 5
0.250.4zone 4
0.250.4zone 3
0.250.25zone 2
0.250.25zone 1
C (used in Riverdale and Nucor with Leidenfrost)
C (used in Riverdale without Leidenfrost effect)
zone no.
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 11
Surface Temperature Down Strand
800
900
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1400
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0 2000 4000 6000 8000 10000 12000 14000 16000
0 20 40 60 80 100 120 140 160 180 200 time (s)
Distance below Meniscus (mm)
Sur
face
Tem
pera
ture
(o C
)Example: Riverdalethin slab caster4.445 m/minmold
spray zone(rolls)
No.1–No.5
supporting rollsno sprayNo.6–No.12
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 12
Zones in CON1D file at Riverdale caster
0.0825113562(12)0.0825112962(11)0.0825112262(10)0.0825111562(9)
0.0617900(8)117300(7)
0.0216075(6)0.082574647(5)0.082573240(4)
0.0691800(3)141105(2)
0.0211040(1)
roll radius(m)# of rollsZone startsZone No.
14562.0 End of last spray zone (mm)( ) – CON1D Zone No.
Spray zones
No spray
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 13
shear pyrometer
Pyrometer #2
bend pyrometer
Pyrometer locations
Pyrometer #1
Two-color-pyrometers#1’, #2’ and #3’
Trial 1(Sep11): pyrometer #1, #2&shear pyrometerTrial 2(Ovt19): bend&shear pyrometerTrial 3(Mar12): two-color-pyrometers, bend&shear pyro
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 14
Casting conditions
Spray water flow rate L/min/row
88.6862.1991.39116.2692.4770.3zone5
116.2690.8476.9797.5787.4892.47Zone4
104.3078.65368.11411.64398.3984.96Zone3
448.55378.52253.61257.39272.53387.98Zone2
283.89276.3219.419.421.7264.95Zone1
19.419.419.419.421.721.7Tspray °C
154915401551155415551551.7Tpour °C
4.6994.5724.344.474.4454.445Vcast m/min
6:30-8:00 Mar12
3:20-5:00 Mar12
9:45-10:25 Oct19
9:10-9:38 Oct19
13:50-14:40 Sep11
12:07-13:40 Sep11Time
Case6case5case4case3case2case1Parameter
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 15
Casting conditions
C 0.21,Mn 0.7, S 0.005, P 0.009, Si 0.04, Cr 0.03, Ni 0.03, Cu 0.03, Mo 0.02, Ti 0.002, Al 0.035, V 0.006, N 0.005
Steel composition (%):
1451Slab width (mm)
55Slab thickness (mm)
Same conditions for case1~6
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 16
Pyrometer measurement: case 1 and 2
Tem
pera
ture
(F
)
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 17
Pyrometer measurement: case 5 and 6
Two-color-temperature T1: calculated by #1’’
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 18
Pyrometer measurement: case 5 and 6
Two-color-temperature T2: calculated by #2’’
Measured temperature goes up from case5 to case6
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 19
Simulation and comparison
• case 1
800
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0 2000 4000 6000 8000 10000 12000 14000 16000
Sur
face
Tem
pera
ture
(°C
)
Distance below meniscus (mm)
CON1D: Shell Surface Temperature
case1(Sep-11)shear pyrometer
pyrometer #1pyrometer #2
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 20
Simulation and comparison
• case 2
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Sur
face
Tem
pera
ture
(°C
)
Distance below meniscus (mm)
CON1D: Shell Surface Temperature
case2(Sep-11)shear pyrometer
pyrometer #1pyrometer #2
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 21
Simulation and comparison
• case 3
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Sur
face
Tem
pera
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(°C
)
Distance below meniscus (mm)
case3(oct19)bend pyrometershear pyrometer
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 22
Simulation and comparison
• case 4
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Sur
face
Tem
pera
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(°C
)
Distance below meniscus (mm)
case4(0ct19)bend pyrometershear pyrometer
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 23
Simulation and comparison
• case 5
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Sur
face
Tem
pera
ture
(°C
)
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CON1D: Shell Surface Temperature
case5(Mar-12)Riverdale installed pyros
Goodrich two-color T1Goodrich two-color T2
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 24
Φ165Φ165
0
100
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5200 5300 5400 5500 0
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Sur
face
Tem
pera
ture
(°C
)
h (W
/m^2
K)
Distance below meniscus (mm)
close up comparison with two-color-temperature
case5(Mar-12)Goodrich two-color T1Goodrich two-color T2
total heat transfer coefficient
Spray impinging region
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 25
Simulation and comparison
• case 6
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0 2000 4000 6000 8000 10000 12000 14000 16000
Sur
face
Tem
pera
ture
(°C
)
Distance below meniscus (mm)
CON1D: Shell Surface Temperature
case6(Mar-12)Riverdale installed pyros
Goodrich two-color T1Goodrich two-color T2
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 26
Φ165Φ165
0
100
200
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5200 5300 5400 5500 0
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Sur
face
Tem
pera
ture
(°C
)
h (W
/m^2
K)
Distance below meniscus (mm)
close up comparison with two-color-temperature
case6(Mar-12)Goodrich two-color T1Goodrich two-color T2
total heat transfer coefficient
Spray impinging region
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 27
Comparison of case 5 and 6
700
800
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0 2000 4000 6000 8000 10000 12000 14000 16000
Sur
face
Tem
pera
ture
(°C
)
Distance below meniscus (mm)
CON1D: Shell Surface Temperature
case5(Mar-12)case6(Mar-12)
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 28
Simulation and comparison
• The predictions are generally reasonable, being 1°C-43°C higher than pyrometers, (except for case3 at the shear position and case4).
• Increasing water flow rate (by ~25%) from case 5 to case 6 caused an increase in measured strand temperature (of 30°C in the strand, 13°C at the bend, and 3°C at the shear) Not expected in the model. The model predicted decreases of 50°C, 5°C, and 3°C.
• Reasons: a gas / water film barrier that decreased heat extraction with increasing water flow. Heat extracted by different rolls might vary with casting conditions such as waterflow rate.
• Further investigation of accuracy of pyrometer measurements is also recommended.
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 29
Consider Leidenfrost for Riverdale case 1~2
700
800
900
1000
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1200
1300
1400
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0 2000 4000 6000 8000 10000 12000 14000 16000
Sur
face
Tem
pera
ture
(°C
)
Distance below meniscus (mm)
CON1D: Shell Surface Temperature
case1(Sep-11)shear pyrometer
pyrometer #1pyrometer #2
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0 2000 4000 6000 8000 10000 12000 14000 16000
Sur
face
Tem
pera
ture
(°C
)
Distance below meniscus (mm)
CON1D: Shell Surface Temperature
case2(Sep-11)shear pyrometer
pyrometer #1pyrometer #2
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 30
Consider Leidenfrost for Riverdale case 3~4
600
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0 2000 4000 6000 8000 10000 12000 14000 16000
Su
rfac
e T
empe
ratu
re (
°C)
Distance below meniscus (mm)
case3(oct19)bend pyrometershear pyrometer
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Su
rfac
e T
empe
ratu
re (
°C)
Distance below meniscus (mm)
case4(0ct19)bend pyrometershear pyrometer
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 31
Consider Leidenfrost for Riverdale case 5~6
600
700
800
900
1000
1100
1200
1300
1400
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0 2000 4000 6000 8000 10000 12000 14000 16000
Su
rfac
e T
empe
ratu
re (
°C)
Distance below meniscus (mm)
CON1D: Shell Surface Temperature
case5(Mar-12)Riverdale installed pyros
Goodrich two-color T1Goodrich two-color T2
600
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1000
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0 2000 4000 6000 8000 10000 12000 14000 16000
Su
rfac
e T
empe
ratu
re (
°C)
Distance below meniscus (mm)
CON1D: Shell Surface Temperature
case6(Mar-12)Riverdale installed pyros
Goodrich two-color T1Goodrich two-color T2
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 32
Consider Leidenfrost for Riverdale case 5~6
0
100
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Su
rfac
e T
empe
ratu
re (
°C)
h (W
/m^2
K)
Distance below meniscus (mm)
close up comparison with two-color-temperature
case5(Mar-12)Goodrich two-color T1Goodrich two-color T2
total heat transfer coefficient
0
100
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5200 5300 5400 5500 0
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Su
rfac
e T
empe
ratu
re (
°C)
h (W
/m^2
K)
Distance below meniscus (mm)
close up comparison with two-color-temperature
case6(Mar-12)Goodrich two-color T1Goodrich two-color T2
total heat transfer coefficient
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 33
Pyrometer locations at Nucor
Pyrometer 1
Pyrometer 2
Pyrometer 3
Pyrometer 4
Pyrometer 5
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 34
Pyrometer locations at Nucor
11385 mmLocation of Pyrometer 4 from meniscus
13970 mmLocation of Pyrometer 5 from meniscus
8380 mmLocation of Pyrometer 3 from meniscus
6015.3 mmLocation of Pyrometer 2 from meniscus
3866.1 mmLocation of Pyrometer 1 from meniscus
15.5 mmFocus spot size
1346 mmLength
Modline® 5, 5R-141000, 4M5#25579Model Name and Number
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 35
Experiments at Nucor
01/13/06
1610-1640
01/16/06-
0945-1012
01/13/06-1535-1610
01/13/06-
0950-1010
Time
Transient4
Steady3
Steady2
Steady1
Steady/Transient
Case Number
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 36
Casting conditions for Nucor case 1~3
case3case2
NorthSouth
1556.9 oC1547.8 oC
14
3.03 m/min3.61 m/min
9:45-10:12Jan13, 2006
15:35-16:10Jan13, 2006
1542.2 oCPouring Temperature
NorthCaster
9:50-10:10 Jan13, 2006
Time of Experiment
C 0.247, Mn 1.09, S 0.0019, Al 0.039, Ca 0.0018, Si 0.175, P 0.014, Cu 0.087, N (leco) 0.0076
Composition (%)
2Spray Pattern No.
3.44 m/minCasting Speed
case1Parameter
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 37
Consider Leidenfrost for Nucor case 1
700
800
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1100
1200
1300
0 2000 4000 6000 8000 10000 12000 14000 16000
Sur
face
Tem
pera
ture
(°C
)
Distance below meniscus (mm)
CON1D: Shell Surface Temperature
case1(Nucor)pyrometer #1pyrometer #2pyrometer #3pyrometer #4pyrometer #5
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 38
Consider Leidenfrost for Nucor case 2
700
800
900
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1200
1300
0 2000 4000 6000 8000 10000 12000 14000 16000
Sur
face
Tem
pera
ture
(°C
)
Distance below meniscus (mm)
CON1D: Shell Surface Temperature
case2(Nucor)pyrometer #1pyrometer #2pyrometer #3pyrometer #4pyrometer #5
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 39
Consider Leidenfrost for Nucor case 3
700
800
900
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1200
1300
0 2000 4000 6000 8000 10000 12000 14000 16000
Sur
face
Tem
pera
ture
(°C
)
Distance below meniscus (mm)
CON1D: Shell Surface Temperature
case3(Nucor)pyrometer #1pyrometer #3pyrometer #4pyrometer #5
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 40
Transient case 4 at Nucor
SouthCaster
Jan. 13, 1610-1640 hrs.Time of Experiment
1547.777 oCPouring Temperature
C 0.247, Mn 1.09, S 0.0019, Al 0.039, Ca 0.0018, Si 0.175, P 0.014, Cu 0.087, N (leco) 0.0076
Composition of Elements (%)
4 to 7Spray Pattern No.
142.1 ipm (3.61 m/min) (0.06 m/s)Casting Speed
Case 4Parameter
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 41
Case 4 Spray Pattern Change
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 42
Case 4 Spray Pattern Change
Pyrometer 1 3866.1 mm
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 43
Conclusions
• CON1D model with Leidenfrost effect matches well with both Riverdale and Nucor caster measurements
• Transient behavior seems to be modeled reasonably
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 44
Ongoing work
• Further calibration– use better h-multipliers for incorporating
Leidenfrost effect
– change flat top heat transfer profile to wedge top profile
• Study transient cases with spray pattern and casting speed variation
University of Illinois at Urbana-Champaign • Metals Processing Simulation Lab • H Li 45
Acknowledgements
• Continuous Casting Consortium Members (Nucor, Postech, LWB Refractories, Algoma, Corus, Labein, Mittal Riverdale, Baosteel, Steel Dynamics)
• National Science Foundation– GOALI DMI 05-00453 (Online)
• Other Graduate students, especially K. Zheng, B. Petrus