numerical modelling of ingot charging configurations at pro-tec cgl2

Numerical Modelling of Ingot Numerical Modelling of Ingot Charging Configurations at Charging Configurations at

Pro-Tec CGL2Pro-Tec CGL2

J.R. McDermid, Noranda Inc. - Technology

B.M. Maag, Pro-Tec Coating Co.

M. Gaug, Maya Heat Transfer Technologies

94th Galvanizer’s Association Meeting

Dearborn, MI

McDermid, Maag and Gaug: Numerical Modelling of Ingot Charging Configurations at Pro-Tec CGL2

slide 2

Outline

IntroductionNumerical Model DetailsResults and Discussion

• General Observations

• Detailed Case ResultsConclusions


slide 3

Introduction

Numerical and physical modelling has evolved to become a powerful tool for understanding the factors which control and can alter flow in the CGL bath• many papers presented on this subject at the GA,

Galvatech and other conferences

Solutions now encompass the coupled thermally driven (buoyancy) flow as well as the strip-driven viscous drag flow• significant effect of ingot melting on the flow field in

the charging area


slide 4

Introduction - cont’d

Some practical applications of numerical modelling without the thermal solution have been published• snout flow - references 9 and 11

• dross management - reference 12

Objective of the present work:• Use coupled thermal solution to determine the effect

of different charging configurations on the flow field in the Pro-Tec CGL2 bath

• Use these results to aid in the selection/specification of a new ingot charger by Pro-Tec


slide 5

Numerical Modelling Procedure

Model consisted of a half-bath with a symmetry plane along the long axis of the CGL bath

Model meshing and calculation were performed at Maya Heat Transfer Technologies under the supervision of M. Gaug• further details on the methodology and calculation

boundary conditions can be found in the paper


slide 6

Numerical Model Geometry

inductor

inductor

pot rolls

symmetry planesnoutingots

sink roll

steel sheet

baffle


slide 7

Numerical Modelling Cases

Low Middle High

strip width 1.07m (42 in.) 1.65m (65 in).

strip speed99.1m/min(325 fpm)

137.2m/min(450 fpm)

ingot positioncentre

verticalcentre

horizontal2 offsetvertical

baffle in out


slide 8

Results - General Observations

Changing the strip width/speed• minor effect on the magnitude of the flow velocities, but

not the overall fluid flow pattern

• some effect on the temperature field due to varying heat input rates, but temperature was controlled to 460ºC and overall effect was minor

Overall circulation pattern consistent with that observed by previous authors

Presence or absence of the baffle determines the shape of the overall flow within the CGL


slide 9

General Flow Pattern in CGL Bath


slide 10

General Observations - cont’d

There were significant differences in the flow patterns between the centreline and offset ingot charging configurations• overall flow pattern a strong function of the baffle’s

presence

For simplicity, all results presented further are for the 1.65 m (65 in.) strip at 99.1 m/min. (325 fpm) case• all velocity plots range of 0 - 0.150 m/s

• all temperature plots range of 458 - 463ºC


slide 11

Results - Detailed Observations

The model visualisations were performed via 2D cutting planes at various distances from reference planes• X-Y plane parallel to symmetry plane (reference

plane)

• X-Z plane parallel to top surface plane of the CGL bath (reference plane)


slide 12

VC Ingot - X-Y (0.127m) w/o baffle velocity

ingo

tpot rolls

snout


slide 13

VC Ingot - X-Y (0.127m) w/ baffle velocity

baffle


slide 14

VC Ingot - X-Y (0.127m) w/o baffle temp.


slide 15

VC Ingot - X-Y (0.127m) w/ baffle temp.


slide 16

VC Ingot - X-Z (1.270m) w/o baffle velocity


slide 17

VC Ingot - X-Z (1.270m) w/ baffle velocity

inductor


slide 18

VC Ingot - X-Z (1.270m) w/o baffle temp.


slide 19

VC Ingot - X-Z (1.270m) w/ baffle temp.


slide 20

HC Ingot - X-Y (0.050m) w/o baffle temp.


slide 21

HC Ingot - X-Y (0.050m) w/ baffle temp.


slide 22

OV Ingot - X-Y (1.219m) w/o baffle velocity

ingo

t


slide 23

OV Ingot - X-Y (1.219m) w/ baffle velocity


slide 24

OV Ingot - X-Y (1.219m) w/o baffle temp.


slide 25

OV Ingot - X-Y (1.219m) w/ baffle temp.


slide 26

OV Ingot - X-Z (1.270m) w/o baffle velocity


slide 27

OV Ingot - X-Z (1.270m) w/ baffle velocity


slide 28

OV Ingot - X-Z (1.270m) w/o baffle temp.


slide 29

OV Ingot - X-Z (1.270m) w/ baffle temp.


slide 30

Conclusions The macroscopic/melting ingot flow calculated for the

Pro-Tec CGL2 bath is in general agreement with those of previous authors.

The presence or absence of the deep baffle behind the snout has the largest effect on the bath flow - when present, it effectively isolates the charging area from the remainder of the bath with communication via flow under and around the edges of the baffle.

There are only slight difference between the VC and HC charging cases - orientation factors.


slide 31

Conclusions - cont’d

The OV charging case is significantly different from the VC and HC cases• interaction of the descending ingot flow with the

return flow along the side walls and the rising inductor flow.

• ingot material swept along the back wall of the pot before being drawn to the snout by the drag flow from the sheet.

• overall pattern continues to be dominated by the baffle.


slide 32

Acknowledgements

The authors would like to thank Noranda Inc. and Pro-Tec Coating Co. for their permission

to publish this paper.

numerical modelling of ingot charging configurations at pro-tec cgl2

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