CEP Short Term Course on “Finite Elements in Analysis and Design Using ANSYS”, Dr.J.M.
Mallikarjuna,
Department of Mechanical Engineering; Indian Institute of Technology Madras
2D Thermal Static Analysis of Chimney
Problem: Consider a small chimney constructed from two different materials as shown in figure
below with its dimensions. The inner layer is constructed from concrete with a thermal
conductivity 0.07 Btu/hr-in°F. The outer layer of the chimney is constructed from bricks with a
thermal conductivity 0.04 Btu/hr-in°F. The temperature of the hot gases on the inside surface of
the chimney is assumed to be 140°F, with a convection heat transfer coefficient of 0.037 Btu/hr-
in2-0F. The outside surface is exposed to the surrounding air, which is at 10°F, with a
corresponding convection heat transfer coefficient of 0.012 Btu/hr-in2 0F. Determine the
temperature distribution within the concrete and the brick layer under steady-state conditions.
Also, plot the heat fluxes through each layer. Solve the problem using ANS YS.
GUI Solution:
1. Starting:
Click → start → ANSYS → ANSYS product launcher:
Launch – ANSYS Multiphysics
File management → browse the directory for saving and retrieving the files.
Click → run
2. Preferences → tick → thermal → select h-method → ok
3. Title:
Utility menu → File → Change title → “Chimney” → ok.
Utility menu → plot → replot
1
CEP Short Term Course on “Finite Elements in Analysis and Design Using ANSYS”, Dr.J.M.Mallikarjuna,
Department of Mechanical Engineering; Indian Institute of Technology Madras
4. Elements:
Main menu → Preprocessor → element type → add → add → thermal → solid → quad
4node → ok
5. Material Properties:
Main menu → Preprocessor → material properties → material models → material model 1
→ thermal → conductivity → isotropic → enter KXX1 = 0.07 → ok
Material → new model → material ID 2 → material model 2 → thermal → conductivity →
isotropic → enter KXX2 = 0.04 → ok
6. Modeling:
Main menu → Preprocessor → Modeling → create → area → rectangle → by centr &
corner → enter 0,0,26,26 → ok
Main menu → Preprocessor → Modeling → create → area → rectangle → by centr &
corner → enter 0,0,13,13 → ok
Main menu → Preprocessor → Modeling → operate → boolean → subtract → area →
select base area → ok → select subtracting area → ok
Main menu → Preprocessor → Modeling → create → area → rectangle → by centr &
corner → enter 0,0,13,13 → ok
Main menu → Preprocessor → Modeling → create → area → rectangle → by centr &
corner → enter 0,0,12,12 → ok
Main menu → Preprocessor → Modeling → operate → boolean → subtract → area →
select base area → ok → select subtracting area → ok
Main menu → Preprocessor → Modeling → operate → boolean → glue → area → pick all
→ ok.
Main menu → Preprocessor → Meshing → size cntrl → manual size → global → size →
enter SIZE as 0.25 → ok
Main menu → Preprocessor → meshing → mesh attributes → default attributes → select
element 1 ; material 1 → ok
Main menu → Preprocessor → Meshing → mesh tool → mesh → areas → pick brick area
→ ok
Main menu → Preprocessor → Meshing → mesh attributes → default attributes → select
element 1 ; material 2 → ok
Meshing → mesh tool → mesh → areas → pick concrete area → ok
2
CEP Short Term Course on “Finite Elements in Analysis and Design Using ANSYS”, Dr.J.M.Mallikarjuna,
Department of Mechanical Engineering; Indian Institute of Technology Madras
7. Boundary Conditions:
Main menu → solution → define loads → apply → thermal → convection → on lines →
select by mouse; all outer lines → ok → enter 0.012 & 10 → ok
Main menu → solution → define loads → apply → thermal → convection → on lines →
select by mouse; all inner lines → ok → enter 0.037 & 140 → ok
8. Solution:
Main menu → Solution → solve → current LS
9. Post Processing:
Gen. post processor → plot results → nodal solu → DOF solu → temperature → OK (to
plot temperature distribution)
Gen. post processor → plot results → nodal solu → DOF solu → thermal gradient →
thermal gradient vector sum → OK (to plot thermal gradient)
Path Operations:
Gen. post processor → path operations → define path → on working plane → arbitrary path
→ ok → select two points on the working plane to define the path → ok → enter NAME as
path-AA → ok
Gen. post processor → path operations → map onto path → enter TEMP → DOF solution
→ temperature → ok
Gen. post processor → path operations → plot path items → on graph → select TEMP → ok
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