Lesson 3:
Transient Conduction
Here the method for obtaining a transient temperature solution is illustrated. This time we have a homogeneous slab with a hole in it. The boundary conditions on this slab are illustrated in the figure shown below. We want to perform calculations for the first 50 seconds after the boundary conditions have been suddenly applied to the slab.
To obtain a transient solution follow the procedure shown below.
I am not going to show you how to build the model again because the
basic procedure is essentially identical to the one used for the steady
state model. I will begin from the point where we enter the solution mode
after completing the preprocessing stage.
ANSYS Commands for the Transient Problem
The model creation and element generation stage is very similar to that illustrated in the steady state slab problem. The application of the various loads is also done in a manner similar to that demonstrated in the steady state problem. The following commands will therefore only focus on the specifics of the transient solution method.
To obtain a FEM solution
New Analysis \click (green box on left under Analysis type)
Transient \click
OK \click
Time/Frequency \click (green box on left)
Time and Time step \click
Fill in the particulars as desired
OK \click
Output Ctrls \click
Solu Printout \click
Print Frequency (Every substep)
Output Ctrls \click
DB/Results File \click
File write Frequency (Every substep)
Other \click
Reference Temperature \click
Enter reference temperature
Loads - Apply \click
On nodes \click
Uniform Temperature \click
Enter Initial temperature
OK \click
Current LS \click (green box on left in the Solve area)
OK \click
Wait for solution
Finish \click (green box on left)
This finishes the solution phase of the problem
Postprocessing
This is where you get all the nice colored plots !!!
General Postproc \click (top of screen)
By Load Step \click (in the Read Results area)
Enter the Load step and sub step number
OK \click
Nodal solution \click (in the contour plot area)
OK \click
This should give you a nice contour plot of the temperature field in the composite slab. Notice how the contour lines are perpendicular to the edge of the hole and the top and bottom edge of the model indicating zero temperature gradient and hence a zero heat flux on those surface.
Next step \click (to get plots for next time step)
Now repeat plotting procedure.
You can even do cool animations
PlotCtrls \click (blue menu on top)
Animate \click
Contours over time \click
Make sure to click on Temp in the Val1 area \click
OK \click
Finish \click
File \click (blue menu top)
Exit \click
Save Everything \click
OK \click
THIS CONCLUDES THE TRANSIENT SLAB PROBLEM
Transient Conduction
Here the method for obtaining a transient temperature solution is illustrated. This time we have a homogeneous slab with a hole in it. The boundary conditions on this slab are illustrated in the figure shown below. We want to perform calculations for the first 50 seconds after the boundary conditions have been suddenly applied to the slab.
ANSYS Commands for the Transient Problem
The model creation and element generation stage is very similar to that illustrated in the steady state slab problem. The application of the various loads is also done in a manner similar to that demonstrated in the steady state problem. The following commands will therefore only focus on the specifics of the transient solution method.
To obtain a FEM solution
New Analysis \click (green box on left under Analysis type)
Transient \click
OK \click
Time/Frequency \click (green box on left)
Time and Time step \click
Fill in the particulars as desired
OK \click
Output Ctrls \click
Solu Printout \click
Print Frequency (Every substep)
Output Ctrls \click
DB/Results File \click
File write Frequency (Every substep)
Other \click
Reference Temperature \click
Enter reference temperature
Loads - Apply \click
On nodes \click
Uniform Temperature \click
Enter Initial temperature
OK \click
Current LS \click (green box on left in the Solve area)
OK \click
Wait for solution
Finish \click (green box on left)
This finishes the solution phase of the problem
Postprocessing
This is where you get all the nice colored plots !!!
General Postproc \click (top of screen)
By Load Step \click (in the Read Results area)
Enter the Load step and sub step number
OK \click
Nodal solution \click (in the contour plot area)
OK \click
This should give you a nice contour plot of the temperature field in the composite slab. Notice how the contour lines are perpendicular to the edge of the hole and the top and bottom edge of the model indicating zero temperature gradient and hence a zero heat flux on those surface.
Next step \click (to get plots for next time step)
Now repeat plotting procedure.
You can even do cool animations
PlotCtrls \click (blue menu on top)
Animate \click
Contours over time \click
Make sure to click on Temp in the Val1 area \click
OK \click
Finish \click
File \click (blue menu top)
Exit \click
Save Everything \click
OK \click
THIS CONCLUDES THE TRANSIENT SLAB PROBLEM
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Lesson 2, Steady State Conduction |
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Tutorial Index |
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Lesson 4, Thermal-Structural Analysis |