| Author | Message | |||
     Soumen Kar (soumen) New member Username: soumen Post Number: 2 Registered: 10-2009 |
I want to do 1D thermal analysis of a material which has 3 regions but the area and length of the 3 regions are not same. The boundary temperature of 3 regions are also not same but these 3 regions are coupled with each other. The heat flux is flowing from hot to cold end. Please help me to get a good result. If you can provide me an example with 3 regions like my case then it will be a great help for me. | |||
| Soumen Kar (soumen) Junior Member Username: soumen Post Number: 3 Registered: 10-2009 |
I want to do 1D thermal analysis of a material which has 3 regions but the area and length of the 3 regions are not same. The boundary temperature of 3 regions are also not same but these 3 regions are coupled with each other. The heat flux is flowing from hot to cold end. Please help me to do this simulation because right now I could not do this because no example is there in the FlexPde. If you can provide me an example with 3 regions like my case then it will be a great help for me. | |||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 1302 Registered: 06-2003 |
If you mean that you have something like three rods of different diameter butted end-to-end, then you can simply multiply the conductivity by the cross-sectional area of each rod. This will not give the precise answer at the transition points, but it should be close. The other alternative is to use a 2D axisymmetric model, which should give the right behavior at the transition (for cylinders). If this is not your geometry, you will have to explain it a little more clearly. | |||
| Soumen Kar (soumen) Member Username: soumen Post Number: 4 Registered: 10-2009 |
I can not do it in 2D axisymmetric model because it is not a cylinder. Only 1D model I can use. You please see my codes and suggest me what I can do for this 3 regions. Material properties you can take arbitrarily. I am taking those values from some table.
| |||
| Marek Nelson (mgnelson) Moderator Username: mgnelson Post Number: 147 Registered: 07-2007 |
You seem to have set up your regions correctly. Since you did not provide your tables, I just arbitrarily put in some values for K, Cp, R and the initial temp. The script runs very slowly because the plots you have requested are clamping the time step. You may have wanted that, but the problem runs in about one second if I remove the timed plots and plot every CYCLE instead. I have attached the modified file.
| |||
| Soumen Kar (soumen) Member Username: soumen Post Number: 5 Registered: 10-2009 |
Hii, I have some problem with the boundary and different areas in this program. My program is not correct to judge the result. The main problem is that I am not getting heat flux is flowing from hot to cold end even though the boundary temperature is fixed. I should get some slow temperature rise in the boundaries also. For example, I have boundary temperatures 10, 12 (region 1) then 12, 250 (region 2) but I am not getting any temperature change at the boundaries due to heat flux flow and due to different area. I think that the boundary temperature should not be fixed when the source term is changing due to change in area of each region. Please suggest me how to avoid this problem for 3 regions. | |||
| Marek Nelson (mgnelson) Moderator Username: mgnelson Post Number: 149 Registered: 07-2007 |
You have set VALUE boundary conditions at the ends of each region. There can be no increase in temperature at these points since you have requested them to stay at a constant value. Removing the internal VALUE BCs would give you NATURAL (the default) internal BCs and this is probably what you want. |
Example