Error when setting a biggest end time value


#1

Hi everyone,

Please, I’m trying to simulate a transient flow into a furnace for 100 seconds. It is crashing at around 12s but the Run Event Log is not showing the error and I don’t found it in the solver log, look:

The error don’t occured when I inputed the end time value for 2seconds but I need to simulate for 100seconds. What do you suggest me?
So, my project is here. Run 2 was runned (2seconds), and the problem is in Run 3 (100seconds).

Thank’s in advance!!

Best,

Vinícius


#2

Hi Vinicius (@vgon_alves)!

The @PowerUsers_CFD and me will of course have a look at it but can you first tell us what you want to simulate first? The more input we get from your side the easier it is to identify wrong modeling assumptions made by you.

Thanks and all the best!

Jousef


#3

Hi Jousef!
Sure, first of all thanks for reply! Well, I would like to simulate a multiphase flow inside an Electric Arc Furnace wich is filled with liquid steel. The objective is compare the benefit of change the 120mm (diameter) Eccentric Bottom Tapping (Outlet of the furnace) to another one of 130mm.

Thus, what you are seeing below is the first state of the flow, at 0s when the valve is closed, with 120mm valve.

For the converged simulation (2 seconds), I had obtained this profile below, but 2 seconds are not enough to simulate the flow to its end. (Was estimated about 150 seconds for 40 tonnes of liquid steel, which is what is being simulated);

Please, let me know if there is another point to clear

Thanks and all the best!

Vinícius


#4

Hi Vinícius!

Got it! Let me test some runs later on and get back to you asap. Feel free to jump in @Get_Barried!

Best,

Jousef


#5

Hi @vgon_alves,

From my initial guess, I see an immediate problem.

You have flow exiting the geometry but no flow coming in which will cause a continuity error of sorts. You need have the top of the geometry which i suppose is the open furnace top to represent the atmosphere that has a phrase faction value of 0 to represent air. What the exact boundary condition must be I’m not too sure but it cannot be “forcing” air in and should act passively.

Do try out this methodology and let me know if it works.

Cheers!

Regards,
Barry


#6

Hi @Get_Barried,

Thanks for reply!!
I understood your first point (about continuity error) but here are you’ll have to excuse me about some points:

  • I had already tried to set and inlet-outlet flow, but for some reason that I don’t know it was not saving and I saw it just now (I really don’t know why). But now the BCs are OK.

  • The second point is about the region of outlet flow. Occurs that I set some face, but when I run the simulation another face ocupy the first one. I’d never saw it (but, once again it can be my error when I selected the outlet face). Anyway, now I created a topological entity set wit inlet and outlet faces and every thing is correct about it.

However, the error still occur. I seted the same case with the same BC, but with another geometry now smallest than the furnace geometry. As you can see, the case runs normally in something about 10 seconds to flush the “reservatory”:
Here is a video with the simulation test.

Well, I don’t know if I am clear. If there is any misconception, I beg your pardon, please.

Thank you so much guys!

Best,

Vinícius


#7

Hi @vgon_alves,

Very strange your water case runs well while your liquid metal one doesn’t. If you refer back to your 20s run under “laminar > 20s” it looked like it ran well but you saved too many timesteps under “Write interval (simulation time) [s]”. Setting that value as you did (0.02) for 20s will equate 1000 saved data sets which is way too much. I suggest you save either every half a second (0.5) or second (1) and re-run that specific simulation to see if you can obtain results.

Cheers.

Regards,
Barry


#8

Hi @Get_Barried,

Good suggestion! I’ll try to do it and I get an update asap.

Thanks and all the best!

Vinícius


#9

Hi guys! @Get_Barried @jousefm

Nice to talk with you again!
Look, really the first problem was solved increasing the simulation time value as @Get_Barried had suggested. I have no way to thank you!!

For now, there is an error about CFL exceeding the limit (1). Well, below there are the Numerics and Simulation Control that I chose. Please, if you see something wrong that cause the Courant number exceed 1, give me a feedback.

Error

Numerics

Simulation Control

EDIT1: The Numerics is default and I already tried to increase the Number of correctors, but without success.
EDIT2: Already tried to decrease the mesh quality, but without success too.
All the best for you guys!!

Vinícius


#10

Hi @vgon_alves,

The runs I’ve seen you done have the no of corrects still at 1, you have tried increasing it say 10-20 right?

Also I see one of the runs where you’re currently simulating is doing quite well. Did you change anything in particular?

Cheers.

Regards,
Barry


#11

Hi @Get_Barried,

You’re right, I tried to increase it to 10.

About the current simulation, I am trying to decrease the simulation time using symmentry condition and it is running for now. As soon as these simulations with symetry conditions ends, I’ll turn back the results for you buddy.

All the best and thanks a lot! :slight_smile:

Vinícius


#12

Update: the simulation is running now. The first error was solved applying what @Get_Barried suggested, in other words the problem was at number of saves in the memory. The error about CFL was overcome by decreasing simulation time imposed by symmetry.

Thank you so much for help @Get_Barried and @jousefm!!

Best,

Vinícius


#13

Awesome @vgon_alves!

Props goes all the way to Barry though, he did everything here :smiley: Let us know how things go and keep us up-to-date :slight_smile:

Cheers buddy!

Jousef