Structural modeling and meshing of blast furnace using TCL/Tk scripting

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Simulation Driven Innovation 1

Structural Modeling and Meshing of Blast Furnace Using HyperMesh

And Tcl/Tk.

Debiprasad Ghosh Sr. Manager, Tech cell M&M, L&T Construction 6th Floor, Technopolis, Saltlake-700091, India

Bhaskar Sengupta Head, Tech cell

M&M, L&T Construction 6th Floor, Technopolis, Saltlake-700091, India

Shyam Kr. Maitra Consultant, Tech cell

M&M, L&T Construction 6th Floor, Technopolis, Saltlake-700091, India

Sujan Hazra Sr. Engineer, Tech cell M&M, L&T Construction 6th Floor, Technopolis, Saltlake-700091, India

Abbreviations: FEA- Finite element analysis. Keywords: Blast furnace, TCL/Tk, CDB format, Ansys

Abstract The generation of geometry and meshing is done automatically using HyperMesh with the help of Tcl/Tk scripting language, with a

means to conduct iterative analysis of a blast furnace (an industrial structure) using finite element method. Material properties,

boundary conditions, loading and other input parameters are also given automatically to the script for iterative solution requirements.

Mesh-refinement is generally required at the critical locations for more accurate results. The proposed script in this study will be useful

to analyze any dimensions of blast furnace, material properties, loading and at different orders of discretization. These results are taken

by a designer to design a safe and economical blast furnace for an industry.

Introduction

More than 85% of the world steel production is through the blast furnace route. Blast furnaces continue to

be the prime choice on account of versatility of operation, large production volume and lower cost of

production. However, Blast Furnaces are not only capital intensive, they also require significant time for

design & erection of the various components comprising the Blast furnace shell, its refractory cooling

arrangements, charging equipment, gas cleaning plant, cast house equipment, blast furnace hearth

refractory etc. This paper discusses an approach where the Blast Furnace is designed on the basis of a set

of empirical rules applied to a handful of parameters. As a first attempt, some components of the Blast

Furnace have been ignored - cooling arrangement, up-comers, charging equipment & blast equipment.

Because of the huge financial impact, all efforts are made to design a reliable & economical Blast Furnace,

one that will have a long campaign life and achieve a throughput in excess of 8500 t/day.

In the present paper we are using Ansys for finite element analysis (FEA) and HyperMesh for FEA meshing

of blast furnace [Figure 1]. The function of a blast furnace is to chemically reduce and physically convert iron

oxides into liquid iron called "hot metal". The blast furnace is a huge, steel stack lined with refractory brick,

where iron ore, coke and limestone are dumped into the top, and preheated air is blown into the bottom [1,

2, 3]. The raw materials require 16 to 18 hours to descend to the bottom of the furnace where they become

the final product - liquid slag and liquid iron. These liquid products are drained from the furnace at regular

intervals. The hot air that is blown into the bottom of the furnace ascends to the top in 6 to 8 seconds after

reacting with the raw materials. Once a blast furnace is started it will continuously run for four to ten years

with only short stops to perform planned maintenance.

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Process Methodology

Geometric modelling of blast furnace is created in HyperMesh with required material properties, boundary

conditions and loading. Finite element meshing is obtained from HyperMesh, which is then exported to a

text file of Ansys CDB format. Finally, Ansys-mechanical solver performs the finite element solution and

provides result in “.rst” format, which is imported from HyperView for iterative modification. These repetitive

modelling, meshing and solution are performed using HyperMesh TCL/Tk programming integrating with

HyperMesh GUI.

Figure 1: Overview of program flow

This program requires a handful of input parameters (Blast Furnace Effective Volume: 4000 M3), and on the

basis of a few empirical rules [Ref 1], the program generates the list of tentative Blast Furnace dimensions

(Total Height, Belly Diameter, Hearth Diameter, Tuyere Height, Hearth Height, Blast Furnace top diameter

etc…). Based on experience these dimensions can be edited from HyperMesh UI Tab, and then TCL/Tk

program will generate a “.cdb” file, wherein the geometrical dimensions as well as the mechanical & thermal

loads and the boundary conditions are created in an input file. The iterative steps are outlined in the

schematic, where we check for the maximum seismic and pressure deflections & thermal stresses, and

make changes to the dimensions (Tuyere height 4600 mm), and the loading conditions (the location of the

Simulation Driven Innovation

cooling staves and the cooling water flow rates), then generate a new input file for the next Ansys

simulation.

Total modeling is performed in six

export to CDB format; solution; and Import from HyperView

Solid Modeling: Solid modeling of blast furnace

other set of solid cones. Different parts of a

Throat. The lower part of blast furnace, the hearth

liquid hot metal flows during tapping. In the present model only Firebricks are modeled a

metal/cokes/ore are considered as load.

Outer steel shell of the blast furnace

get nodal coincidence between brick and shell elements.

For simplicity with mapped meshing,

Figure 2

Meshing: Solid modeling of blast furnace

blast furnace under structural and thermal loading

solid model. Mapped meshing is used to get good quality hexagonal brick mesh. Once

created, 2D shell elements for outer steel shell of blast furnace

technique will generate shell elements even for internal, top and

afterward. This deletion of extra shell elements i

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six stages - solid modeling; meshing; application

; solution; and Import from HyperView.

Solid modeling of blast furnace is constructed using a set of solid cones extracted from

Different parts of an iron making blast furnace are Hearth, Boss, Belly,

The lower part of blast furnace, the hearth, consists of a packed bed of coke particles through which

tapping. In the present model only Firebricks are modeled a

are considered as load.

eel shell of the blast furnace is not solid modeled, which is face extracted from 3D brick elements to

get nodal coincidence between brick and shell elements.

For simplicity with mapped meshing, tapholes, tuyeres and staves are not considered in the model.

Figure 2: Interactive modeling of blast furnace using Tcl/Tk

Solid modeling of blast furnace provided 3D geometry of the blast furnace. To g

blast furnace under structural and thermal loading, using finite element analysis, required

Mapped meshing is used to get good quality hexagonal brick mesh. Once

2D shell elements for outer steel shell of blast furnace are face lifted from 3D elements. Such

technique will generate shell elements even for internal, top and bottom surfaces as well, which

etion of extra shell elements is done using following steps

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application of boundary condition;

solid cones extracted from

rth, Boss, Belly, Stack, and

consists of a packed bed of coke particles through which

tapping. In the present model only Firebricks are modeled and internal hot

face extracted from 3D brick elements to

uyeres and staves are not considered in the model.

3D geometry of the blast furnace. To get response of

required meshing of this

Mapped meshing is used to get good quality hexagonal brick mesh. Once 3D elements are

face lifted from 3D elements. Such

as well, which are deleted

Simulation Driven Innovation

1. Get nearest node from a particular point

2. Get the elements connected on face

3. Delete the elements.

Now material and real constant properties a

Application of Boundary Condition:

applied either on solid modeling, or on the generated mesh. In the present paper

applied in the mesh. Nodes at the bottom of blast furnace are considered as structurally fixed

load is taken as 25% of the self weight in the horizontal direction, where the self weight includes the weight

of the structure as well as the weight of the internal burden in the

condition is due to the internal pressure, typically 2

temperature boundary conditions are

give rise to thermal stresses because of the unequal expansion of the refractory lining and the steel shell.

Modern Blast Furnaces have extensive cooling arrangements, and the operational heat loads can fluctuate

by an order of magnitude over their nominal

fluctuations with their attendant thermal stresses, and these also have

at a preliminary design.

Export to CDB Format: Once Model is ready with nodes,

profiles, and Ansys solution commands, these can be exported in Ansys CDB format.

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Get nearest node from a particular point

Get the elements connected on face

and real constant properties are provided for both brick and shell elements.

Figure 3: meshing of blast furnace using Tcl/Tk

Application of Boundary Condition: Application of both thermal and structural boundary condition can be

applied either on solid modeling, or on the generated mesh. In the present paper,

e bottom of blast furnace are considered as structurally fixed


of the structure as well as the weight of the internal burden in the furnace. The second important loading

e internal pressure, typically 2 atmospheres in the modern furnaces.

are applied at bottom, internal, and external wall of the furnace.

ive rise to thermal stresses because of the unequal expansion of the refractory lining and the steel shell.


by an order of magnitude over their nominal values (40 mJ/m2/Hr). These give rise to severe temperature

fluctuations with their attendant thermal stresses, and these also have been ignored in the model

Once Model is ready with nodes, elements, materials, boundary conditions, Ansys


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re provided for both brick and shell elements.

Application of both thermal and structural boundary condition can be

boundary conditions are

e bottom of blast furnace are considered as structurally fixed. The seismic


furnace. The second important loading

in the modern furnaces. Similarly, different

applied at bottom, internal, and external wall of the furnace. These

ive rise to thermal stresses because of the unequal expansion of the refractory lining and the steel shell.


. These give rise to severe temperature

been ignored in the model, to arrive

elements, materials, boundary conditions, Ansys


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Solution: Solution is fired from TCL script using “exec AnsysRun.bat” command within a “try block”, where

“AnsysRun.bat” file contains Ansys batch solver command for finite element solution. Ansys solver which

writes results in Ansys “.rst”/”.rth” file.

Import from HyperView: To view and take design decision, generated Ansys “.rst” or “.rth” file is opened

from HyperView.

Results & Discussions

Figure 4 shows the stress contour of the blast furnace shell for structural and thermal loading.

Figure 4: Stress contour from HyperView

Benefits Summary Manual repetitive modeling of blast furnace is time consuming as well as prone to manual error. Present

technique reduces the requirement of man power and gives opportunity to concentrate on the other

important design issues of blast furnace (design parameters, several alternative cooling stave

configurations) easily, which should be examined before a satisfactory arrangement can be finalized.

Challenges

First challenge we have faced in our project is regarding interoperability between HyperMesh/HyperView

and Ansys, where Altair India and USA technical team had helped to overcome the difficulty. Another

challenge is regarding the TCL/Tk language; as not being an object oriented family. Programmers with big

projects are mostly available for object oriented (Java, C++, C#), or more recently multi-paradigm, functional

languages (Python, F#). Even after development, big projects using other family of languages are difficult to

maintain, extend and test. Anyway, extensive uses of namespaces are applied to overcome this challenge.

Although ScriptView is not yet mature, it also helped a lot.

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Future Plans SolidThinking can be used for solid modeling of blast furnace with tuyeres, and staves. Moreover, these

design technique can be extended using solver and optimization features of Altair software like OptiStruct,

RADIOSS etc…

Conclusions A computational framework is created to model blast furnace in HyperMesh, Analyze in Ansys APDL and

viewing results in HyperView using TCL/Tk programming. Automatic modeling technique had given

opportunity to concentrate on important design related issues.

ACKNOWLEDGEMENTS

The authors would like to thank Subir Roy, Anand Ronad, Dev Anand, Shashi Kumar, Sujatha K G, Jyotsna

Naveen, Rajas Majumdar, Nitin Chirdeep, Ramesha B S, Shashi Mantrawadi, Vishwanath Rao; Anshuman

Panda, Kiran Chakravarthy of Altair Engineering for their kind help during the development of project and

submission of paper in the HTC2012.

REFERENCES

[1] Eu. F. Wegmann, "A Reference Book for Blast Furnace Operator," Translated from the Russian by V. Afanasyev, Mir publishers

Moscow.

[2] M. Geerdes, H. Toxopeus, C. van der Vliet, “Modern Blast Furnace Ironmaking”, Verlog Stahleisen GmbH.

[3] Anil K. Biswas, “Principle of Blast Furnace Ironmaking”, Cootha publishing house.

Technology

Structural modeling and meshing of blast furnace using TCL/Tk scripting