Dear all,
I have found the problem. If somebody is interested: look at "Thermal Analysis Guide" in the documentation, 3.4.3.2/"Number of substeps per load step, or the time step size". Here you will find a formula, which MUST be used, to get good results in transient thermal analysis.
MaxTemp2...
My calculations looks OK.
Due to the help, in ANSYS Classic the results are for the nodes. (See: Release 11.0 Documentation for ANSYS/4.3 - Types of data available for postprocessing - "Primary data consist of the degree-of-freedom solution calculated at each node ... Primary data in thermal...
Sorry to write again, I forget to ask you: do you have Workbench 11.0? If yes, could you please run the problem and tell me results?
I just tried out ANSYS Classic through "Open analysis in ANSYS". The values are OK (everything is the same; Workbench says maximum temp. after 10 sec is 307°C...
Transient1,
I have calculated the results also by hand, and the minimum temperature is in good accordance (the temperature decrease on the convection surface is -0,6°C/s) with those from ANSYS. My problem is, that the maximum temperature is rising steadily above 300°C, which is nonsense, since...
Dear Transient1 (and all others),
after reading your answer again 10-20 times and experimenting, I think, I would like to do another calculation, than that you were thinking, but I have problems anyway. I will try to explain my problem more detailed, I hope you can help:
- geometry: for...
Thank you for your answer Transient1.
I tried what you said (300C on the block, after time-dependent convection boundary on the upper surface), but the max. temperature is going above 300 anyway. I think I am still doing something wrong. :(
Could you please send your solution to the problem? (I...
Dear all,
I have a simple geometry in ANSYS Workbench 11.0 created to study, if it can handle transient thermal analysis. The goal would be later to build a more detailed geometry and solve a coupled structural - (transient)thermal analysis.
After one week trying out everything my conclusion...
I have a solution with a few approximations. The calculation can be found in the Excel sheet attached.
Main approximations:
- Dittus-Boelter calculation can be applied
- water properties do not vary with temperature
- heat transfer coefficient is constant (from previous approximation)
You...
Dear all,
I am trying to debug one of my problems (see: Thermal transient analysis with ANSYS), and I need help. Is there a possibility to exactly see the equations, matrices etc. at each node with/from which ANSYS calculates the temperatures at the nodes?
Thx
MaxTemp2
Applying the loads in small time-steps does not work either.
Everytime I decrease (increase) the ambient temperature, there are parts on the plate, where the temperature increases (decreases).
I think I understand what you mean sailoday. I dont know how to do a 1D analysis in Workbench yet, but I will try to put the load conditions (convection) at a different time, lets say at 10 sec. (Maybe tomorrow, now I should finish working :) )
IRstuff: The 150C is the ambient temperature (bulk...
Dear sailoday28,
Sorry, but i do not understand what you wrote. Can you specify it, please? (For a convection boundary you need to specify film coeff. and ambient temp. also)
Dear all,
I am trying to calculate a simple thermal transient problem in ANSYS Workbench 11.0 to see how it works to make later more complicated calculations. But I have a problem:
My model:
-steel plate (vary simple geometry)
-starting temperature: uniform 300C
-boundary conditions...
