transient natural convection water

erw · August 14, 2018, 01:16

Hello everyone,

My project is to study the heat processing of tomato paste. Let me explain. My geometry is a closed domain and includes the retort (full of water) and the can (tinplate-wall and the inside domain). I "patch" the water at 372.15K and, tinplate and tomato paste at 297.15K. After 1 time step the minimum total temeprature is 1K and the maximum 1742K!!!! I see that is very wrong. I would appreciate if you help me. Thanks a lot for your time.

LuckyTran · August 14, 2018, 13:44

Try doing a few iterations to get a consistent solution before time-stepping.

Instead of:

Code:

solve/dual-time-iterate numSteps numIters

do:

Code:

solve/iterate numIters

You have to do this manually in the TUI. If you click the calculate button from the GUI, it immediately goes to the next time-step (equivalent to solve/dual-time-iterate)

Regardless of whether or not this fixes your problem you should still get a converged solution at time=0. If it blows up and diverges even before time-stepping, then you know you have a bigger problem and time-stepping is not the issue.

erw · August 14, 2018, 13:51

Hello!!!
Thank you for your time.
I don think the time step is my problem. :/
I reduced it at 0.01 and I had similar results.
I can not understand why the temperature is so high.

August 14, 2018, 01:16	transient natural convection water	#1
erw New Member Fanourakis Alexander Join Date: Mar 2017 Posts: 2 Rep Power: 0	Hello everyone, My project is to study the heat processing of tomato paste. Let me explain. My geometry is a closed domain and includes the retort (full of water) and the can (tinplate-wall and the inside domain). I "patch" the water at 372.15K and, tinplate and tomato paste at 297.15K. After 1 time step the minimum total temeprature is 1K and the maximum 1742K!!!! I see that is very wrong. I would appreciate if you help me. Thanks a lot for your time.

August 14, 2018, 13:44		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,753 Rep Power: 66	Try doing a few iterations to get a consistent solution before time-stepping. Instead of: Code: solve/dual-time-iterate numSteps numIters do: Code: solve/iterate numIters You have to do this manually in the TUI. If you click the calculate button from the GUI, it immediately goes to the next time-step (equivalent to solve/dual-time-iterate) Regardless of whether or not this fixes your problem you should still get a converged solution at time=0. If it blows up and diverges even before time-stepping, then you know you have a bigger problem and time-stepping is not the issue.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Natural Convection in 2D Water Heater	lara.croft.	FLUENT	2	June 11, 2016 12:31
Natural convection in the spent fuel pool	Audrius	FLUENT	3	June 14, 2015 10:46
SSIIM 2, vertical elevation of the water surface, transient water flow parameters	Mummputz	Main CFD Forum	6	November 18, 2012 14:39
How model natural convection in water?	Fiska	FLUENT	4	January 28, 2010 04:23
Transient natural convection problem	Ravi	Main CFD Forum	2	January 30, 2000 13:08

August 14, 2018, 13:51		#3
erw New Member Fanourakis Alexander Join Date: Mar 2017 Posts: 2 Rep Power: 0	Hello!!! Thank you for your time. I don think the time step is my problem. :/ I reduced it at 0.01 and I had similar results. I can not understand why the temperature is so high.