I want to simulate 2D pool boiling in Ansys fluent using Eulerian model. Most of research papers available uses VOF model for simulation but there is no information regarding Eulerian RPI boiling model for pool boiling. I tried but there are some issues regarding simulation
1) Continuity equation is not converging below e-03.
2) Confusion regarding interaction models for drag, lift, wall lubrication etc.
3) In animation, there are no vapor bubbles visible
I will appreciate if anyone can give suggestion for these issues and provide some tutorial or research paper of 2D Pool Boiling Simulation Using Eulerian Method (water as fluid)
Computational domain
2D rectangular domain with length 30mm and height 50mm. Turbulence modelling is included with K-e model.
BC,s
Top - pressure outlet at atmospheric pressure
Left and Right walls - Adiabatic
Bottom - At Temp of 380K or more (above 373.15K)
The RPI boiling model has been developed (initially) for pure convective nucleate subcooled boiling. It was initially meant as a model being applied for the subcooled boiling in the vertical cooling channels of nuclear reactor fuel elements. The RPI model has never meant to work for (horizontally oriented) heated wall elements in pool boiling situations.
If you like to enhance the RPI boiling model for pool boiling, then you are in the field of 1st frontier research and you cannot rely on the fact, that a commercial flow solver is providing you with a ready-to-use physical model.
Furthermore it is an entirely wrong expectation, that an (spatially averaged) Eulerian multiphase flow model will provide you with macroscopically visible vapor bubbles. The Eulerian MPF model characterizes the vapor content in the flow by the value of the void fraction. By the applied averaging methodology to derive the transport equations of the Eulerian MPF model, the morphology of the flow is getting lost. This knowledge about the flow morphology needs to be re-introduced by the user of the model from his own particular knowledge about the studied flow phenomenon. The information about the user-assumed flow morphology is introduced to the model by the formulation of the law for the interfacial area density. In the original RPI model this is the underlying assumption, that the flow is a bubbly flow of bubbles of a defined diameter and that the local void fraction has a direct algebraic relationship to that assumed characteristic bubble diameter.
Research papers:
http://www.drthfrank.de/literatur.html
Best regards,
Dr. Th. Frank.
Refer to this work.
https://www.tandfonline.com/doi/epub/10.1080/00295639.2020.1764265?needAccess=true
Regards,
Sachin
Thomas Frank
Thanks sir for your explanation regarding Eulerian RPI boiling model.
Regards
Rajan Jaswal
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