Pool Boiling Eulerian RPI Model Vapor Volume Fraction Problem

tumerkan10 · July 5, 2019, 08:58

Hello everyone;

I am working on Eulerian RPI Model for pool boiling. I used to work on VOF before, but the results of the Twall were not satisfied with my experiment so i choose rpi model to validate experimental results.
Firstly, i faced with the some diverge problems. In explicit method for volume fraction, When i try fine mesh (near the boundary 0.05 mm) it diverges very fast(variable time step, global courant number 2 min time step 1e-7 max 5e-5).So i tried to 0.3mm mesh size near the boundary, Twall, and Qevap was okay, but for vapor volume fraction was like this;

https://i.ibb.co/KszM4CT/3.jpg
My models and correlations are;

https://i.ibb.co/ctNnjGD/1.jpg
I read other articles, i tried their correlations(drag, heat , lift etc), but vapor volume fraction did not change.
For same geometry, when i use VOF, the vapor volume fraction is like that;

https://i.ibb.co/NxNC6JY/2.jpg
Our model, heat flux from side wall;

https://i.ibb.co/QfgnmzN/2.jpg
How can i see bubbles in rpi model?

tumerkan10 · July 7, 2019, 12:36

if you have a tutorial about rpi model, please share with me
e-mail:tumerkanvural@gmail.com

TahminehAd · September 27, 2023, 04:56

Hello, Did You find the answer of your question? I have the same issue in my RPI wall boiling model in fluent. I use the default RPI of fluent with the same set up as you. But the vapor volume fraction doesn't make sense. If you found your answer, is it possible to tell me how you solved it?

July 5, 2019, 08:58	Pool Boiling Eulerian RPI Model Vapor Volume Fraction Problem	#1
tumerkan10 New Member tumer Join Date: Jan 2019 Posts: 2 Rep Power: 0	Hello everyone; I am working on Eulerian RPI Model for pool boiling. I used to work on VOF before, but the results of the Twall were not satisfied with my experiment so i choose rpi model to validate experimental results. Firstly, i faced with the some diverge problems. In explicit method for volume fraction, When i try fine mesh (near the boundary 0.05 mm) it diverges very fast(variable time step, global courant number 2 min time step 1e-7 max 5e-5).So i tried to 0.3mm mesh size near the boundary, Twall, and Qevap was okay, but for vapor volume fraction was like this; https://i.ibb.co/KszM4CT/3.jpg My models and correlations are; https://i.ibb.co/ctNnjGD/1.jpg I read other articles, i tried their correlations(drag, heat , lift etc), but vapor volume fraction did not change. For same geometry, when i use VOF, the vapor volume fraction is like that; https://i.ibb.co/NxNC6JY/2.jpg Our model, heat flux from side wall; https://i.ibb.co/QfgnmzN/2.jpg How can i see bubbles in rpi model? Last edited by tumerkan10; July 6, 2019 at 11:55. Reason: wrong links

July 7, 2019, 12:36	tutorial	#2
tumerkan10 New Member tumer Join Date: Jan 2019 Posts: 2 Rep Power: 0	if you have a tutorial about rpi model, please share with me e-mail:tumerkanvural@gmail.com

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September 27, 2023, 04:56		#3
TahminehAd New Member Tahmineh Join Date: Apr 2022 Posts: 8 Rep Power: 4	Hello, Did You find the answer of your question? I have the same issue in my RPI wall boiling model in fluent. I use the default RPI of fluent with the same set up as you. But the vapor volume fraction doesn't make sense. If you found your answer, is it possible to tell me how you solved it?