ANNUAL REPORT UIUC, August 6, Temperature evolution in the spray zones: plant measurements and CON1D prediction

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1 ANNUAL REPORT 28 UIUC, August 6, 28 Temperature evolution in the spray zones: plant measurements and CON1D prediction Xiaoxu Zhou (MS Student) Brian G. Thomas Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign Acknowledgements Continuous Casting Consortium Members (Baosteel, Corus, Goodrich, Labein, LWB Refractories, Mittal, Nucor, Postech, Steel Dynamics, Ansys Inc.) National Science Foundation GOALI DMI (Online) Other graduate students, especially Huan Li and Bryan Petrus James. University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 2

2 Outline Nucor trials-pyrometer measurements Con1d prediction of Nucor trials Con1d prediction of whale formation Con1d tests of hysteresis Conclusions University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 3 Pyrometers location Pyrometer 1 Pyrometer 2 Pyrometer 3 Pyrometer 4 Pyrometer 5 University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 4

3 Pyrometer Specifications Model Name and Number Length Focus spot size Location of Pyrometer 1 from meniscus Location of Pyrometer 2 from meniscus Location of Pyrometer 3 from meniscus Location of Pyrometer 4 from meniscus Location of Pyrometer 5 from meniscus Modline 5, 5R-141, 4M5# mm 15.5 mm mm 838 mm mm mm 1397 mm University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 5 Spray zones configuration in con1d input file Zone No. Zone Starts # of Rolls Roll Radius (m) (1) 85 1 (1).62 (2) 94 5 (2~6).62 (3) (7~12).62 (4) (13~17).7 (5) (18).8 (6) (19~27).8 (7) (28).95 (8) (29~37).95 (9) (38).95 (1) (39~48).95 (11) (49).115 University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 6

4 Case 4 13 Jan Transient (Low and High Spray) Nucor experiment (from Amar s ccc meeting 26) Parameter Value Time of Experiment Casting Speed Spray Pattern Number Composition of Elements (%) Caster Pouring Temperature Jan. 13, 26, hrs ipm (3.61 m/min) (.6 m/s) 4 to 7 C.247 Mn 1.9 S.19 Al.39 Ca.18 Si.175 P.14 Cu.87 N (leco).76 South o C The casting speed kept constant. The spray pattern went like high-low-high-low-high. University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 7 Experimental Temperature Profile -Amar Behera s Nucor report University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 8

5 Characterize using CON1D --from Vapalahti s 26 ccc meeting report: Delavan Nozzle Characterization at CINVESTAV Water flux (L/m 2 s) Del avan Qw=1. 4 L/ mi n Water flow used in nozzle experiment Heat tran Coeff (W/m2K) Del avan Qw=1. 4 L/ mi n Estimated heat flux profile based on Nozaki correlation Delavan Distance down caster (mm) University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 9 Characterize using CON1D --from Vapalahti s 26 ccc meeting report: Delavan Nozzle Characterization at CINVESTAV Del avan Qw=6. 9 L/ mi n Water flow used in nozzle experiment Water flux (L/m 2 s) Heat tran Coeff (W/m2K) Del avan Qw=6. 9 L/ mi n Estimated heat flux profile based on Nozaki correlation Delavan Distance down caster (mm) University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 1

6 Characterize using CON1D --from Vapalahti s 26 ccc meeting report: Delavan Nozzle Characterization at CINVESTAV Water flux (L/m 2 s) Del avan Qw=8. 5 L/ mi n Water flow used in nozzle experiment Heat tran Coeff (W/m2K) Del avan Qw=8. 5 L/ mi n Estimated heat flux profile based on Nozaki correlation Distance down caster (mm) Delavan University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 11 Characterize using CON1D --from Vapalahti s 26 ccc meeting report: Delavan Nozzle Characterization at CINVESTAV Water flux (L/m 2 s) Heat tran Coeff (W/m2K) Del avan Qw=39 L/ mi n Del avan Qw=39 L/ min Delavan Distance down caster (mm) Water flow used in nozzle experiment Estimated heat flux profile based on Nozaki correlation University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 12

7 Characterize using CON1D --from Vapalahti s 26 ccc meeting report: Delavan Nozzle Characterization at CINVESTAV Water flux (L/m 2 s) Heat tran Coeff (W/m2K) Del avan Qw=25 L/ mi n Del avan Qw=25 L/ min Water flow used in nozzle experiment Estimated heat flux profile based on Nozaki correlation Delavan Distance down caster (mm) University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 13 Characterize using CON1D --from Vapalahti s 26 ccc meeting report: Delavan Nozzle Characterization at CINVESTAV Del avan W19822 Qw=1. 8 L/ mi n Water flow used in nozzle experiment Water flux (L/m 2 s) Heat tran Coeff (W/m2K) Delavan W19822 Del avan W19822 Qw=1. 8 L / min Distance down caster (mm) Estimated heat flux profile based on Nozaki correlation University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 14

8 Con1d prediction of Nucor trails Specific input variables: Model parameters Casting speed Spray length Solid fraction h profile Water flow rates values 3.61 m/min.7 Low High University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 15 Con1d predictions-- case 4_low spray 13 CON1D: Shell Surface Temperature 12 Surface Temperature ( ãc) Distance below meniscus (mm) case4_low spray(nucor) pyrometer #1 pyrometer #2 pyrometer #3 pyrometer #4 pyrometer #5 -Huan s Nucor trial ppt University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 16

9 Con1d predictions-- case 4_high spray 13 CON1D: Shell Surface Temperature 12 Surface Temperature ( ãc) Distance below meniscus (mm) case4_high spray(nucor) pyrometer #1 pyrometer #2 pyrometer #3 pyrometer #4 pyrometer #5 -Huan s Nucor trial ppt University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 17 Con1d predictions (steady state simulation) University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 18

10 Cononline Prediction (transient simulation) University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 19 Observations Compared to pyrometer measurements Con1d gives higher temperature prediction in the spray region except the pyrometer 2 in the case 4_low spray. In order to match pyrometer 2 measurement, the heat transfer coefficient should be increased appropriately around 6 mm down the strand. Pyrometer focuses the thermal radiation onto the detector. However, there is much mist around strand which should decrease the power intensity collected by pyrometers. Then, it is the fact that pyrometer gives lower reading. Thus, Con1d temperature prediction matches reasonably pyrometer measurements in the spray region in these two cases. University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 2

11 whale formation cases Casting conditions (Nucor Dec 9, 23) Casting Speed (ipm) Spray Pattern Case Case Case Observation at Plant No Whale No Whale Whale Containment limit = mm Specific input variables in con1d: Model parameters Spray length Solid fraction h profile values.5 mm for all sprays Flat-top for all sparys ( z1 z2 z3 h1 h2 h3 ) ( ) University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 21.7 Con1d prediction of Case 1 Note: no whale, match the observation Thickness, mm Distance down meniscus,mm Solidus Liquidus Solid Shell surf T Temperature, Deg C University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 22

12 Con1d prediction of Case 2 Note: Solid coincides containment limit Thickness, mm Temperature, Deg C Distance down meniscus,mm Solidus Liquidus Solid Shell surf T University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 23 Con1d prediction of Case 3 Note: whale, match the observation Thickness, mm Temperature, Deg C Distance down meniscus,mm Solidus Liquidus Solid Shell surf T 6 University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 24

13 Con1d prediction of whale formation of case 3 using pointed h profile Input variables: Model paramet ers Casting speed Spray length Solid fraction h profile Water flow rates values m/min (157ipm).7 University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 25 Whale formation Con1d9.6 prediction Case3 Whale observed in the plant for Case 3. Shel l gr owt h & Sur f t emp ( 146i pm Spr ay pat t er n_6) But prediction gives solid far away before containment limit Conclusions: Heat transfer coefficients were too high Temp ( deg c) t hi ckness ( mm) Pyrometer temperatures (which are matched by this run) were reading too low di st ance bel ow meni scus ( mm) Sur f Temp Li qui dus Sol i dus Shel l University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 26

14 Leidenfrost effect with hysteresis Con1d 9.6 was modified to consider hysteresis in Liedenfrost effect: If surface temperature ts next > ts, meaning heating, LF effect is employed. If surface temperature ts next <ts, meaning cooling, LF effect is not employed. Using the following set of h multipliers h-multipliers temperatures University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 27 Hysteresis effect Shell surface temperature, Deg C Distance below meniscus,mm LF effect always ON Hysteresis employed University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 28

15 Hysteresis effect Shell surface temperature,deg C Distance below meniscus,mm Hysteresis employed Hysteresis always OFF University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 29 Conclusion and future work Several CON1D simulations have been combined to show that pyrometer measurements maybe not believable. Hysteresis based on heating / cooling is oversimplified, as fluctuations between rolls made the Leidenfrost effect with hysteresis negligible in test simulations. Parameters are needed to simultaneously match: lab heat extraction measurements at Cinvestav Pyrometer temperatures or TC traces measured at plant Whale formation / shell thickness University of Illinois at Urbana-Champaign Metals Processing Simulation Lab Xiaoxu Zhou 3