I am solving one transient case in Fluent. I have a chamber which is heated by thermal radiation. Once it reaches certain temperature I want to introduce some chemical species which will undergo a chemical reaction. So, I am initially solving the thermal case and then after certain time, I want to stop the solution and patch the species fraction in a certain volume. I tried doing this but solver is ignoring the patched values. I am able to change boundary conditions between but unable to patch the values. Can you suggest any alternative way of doing this?
If you define the time at which the change occurs, you can just make a journal to run the transient simulation for a given time, stop the simulation and then use "Patch" feature of Fluent, and then continue the simulation.
The text ui journal command for patch used to be /solve/patch "name_of_cell_zone" "Variable" "Custom_field*yes/no" "value"
You just need to have the volume which should be patched with a different name, eventually custom field function and the new value. It should not ignore the new values.
If you want to adapt this automaticaly when the temperature reaches a given point, you may need an "adjust" UDF", or possibly two different adjust udf's: one that measures the value, and one that will execute once, in the moment when the value from the first one is obtained. The range of execution may be local (cell) or the whole zone - whatever you prefer.
Thanks for this information.
I tried patching the cell zone through commands.
I solved it for 400s and then patched the cell zone ID with different temperature value and then changed the solution setting to 800s and solved it. (I have just created a dummy case to try this out)
But, the solution starts with the values arrived at 400s.
Is there anything wrong with the procedure I have adopted?
Hi dear Hardik
I think you should notice on all other species fractions, you can not set any amount of species fraction over the patch zone. Consider every species fraction separately that sum of them lead to one.
Dear Seyed,
Thanks for the answer. But, as I told, I am currently trying to patch temperature just to test whether it works or not and solver is ignoring this newly patched values for further calculation.
Once you patch the value, check it with a plot if the value is really patched. Then try to save the case/data at that point, read that saved case/data and continue. If that works, you can write that routine to your journal. The text ui commands for journal are /wcd "name" and /rcd "name"
If after patch the values from simulation are not overwritten for some reason, you should make an UDF that in that cell-zone changes value of temperature to whatever you want, once flow-time value reaches 400 s.
- Badges
- Science topic