|
[Sponsors] |
May 26, 2023, 11:23 |
Very low steam fraction RPI boiling
|
#1 |
Member
Pierre LECHEVALIER
Join Date: Mar 2023
Posts: 31
Rep Power: 3 |
Dear All,
I am currently working on my first CFD boiling simulation using RPI model and I face an issue I can not fix. I have started with a very straightforward steady state situation, vertical tube 20mm diameter and 2000mm length. Water inlet at the bottom at 20°C, 1 bar and 1m/s. I have imposed a heat flux on the wall which i increase gradually simulation after simulation. It appears that the monophasic situation works very well. I activate the multiphase model when the temperature on the wall is about to reach the saturation temperature and that's where the problem start. Indeed, whatever the heat flux imposed, the steam volume fraction remains very low (i can not reach more than e-5). I have tried to increase a lot the heat flux but the solver diverge then... Briefly, my simulation is working very well in monophasic state (even when the multiphase option is activated when the heat flux is low enough) but when the heat flux is high enough to create steam, the fraction remains very low whatever the flux. As it is my first RPI boiling simulation, i am using the "default" values for all the RPI model parameters adviced by Fluent Manual. I precise that I have activated the gravity... Any idea ? Thank you for your help ! Pierre |
|
November 13, 2024, 13:22 |
|
#2 |
New Member
gulab verma
Join Date: Feb 2023
Posts: 2
Rep Power: 0 |
i also want answer for the same. have you got the solution?
|
|
November 13, 2024, 15:29 |
|
#3 |
Member
Pierre LECHEVALIER
Join Date: Mar 2023
Posts: 31
Rep Power: 3 |
Dear gulab1708,
This post is quite old now, but I am still working on this subject, so maybe I can help . I do not know exactly what is your issue but if the situation is close to mine in May 2023 I suggest you to start from the Bartolomei validation case (you will find it on the Ansys Help site). If you have specific question please do not hesitate to ask I will try to help you on this difficult but passionating subject ! You can also send me directly a message/email Best regards, Pierre |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Convergence Issue Of RMS Mass Vapour in RPI Boiling Model in CFX | nomi.tahir | Main CFD Forum | 1 | May 28, 2018 04:56 |
Free surface issues with interDyMFoam for hydroturbine | oumnion | OpenFOAM Running, Solving & CFD | 0 | October 6, 2017 15:05 |
multiphaseEulerFoam (OF2.3.0) : Courant number explodes when running in parallel | Mehrez | OpenFOAM Running, Solving & CFD | 10 | May 18, 2016 12:44 |
CFX Solver Memory Error | mike | CFX | 1 | March 19, 2008 08:22 |
Multicomponent fluid | Andrea | CFX | 2 | October 11, 2004 06:12 |