CFD Online Discussion Forums

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   Fluent Multiphase (https://www.cfd-online.com/Forums/fluent-multiphase/)
-   -   Even with different superheat amount of vapor is same (https://www.cfd-online.com/Forums/fluent-multiphase/224891-even-different-superheat-amount-vapor-same.html)

rupak504 March 7, 2020 02:17
Even with different superheat amount of vapor is same
 
hello,

I am simulating a film boiling phenomenon.

I am using following models:


Multi-phase: VOF
Scheme: Implicit
Turbulence: k-e
Methods: default
Controls: default
Phase change: Lee model (r = 0.1)



My Problem is: Very little difference (almost overlapping in graph) in amount of vapor generation even when degree of super-heat is increased by 45K.



regards

vinerm March 7, 2020 07:34
Pre-existing Vapor
 
What's the fraction of vapor at the initialization? The model requires a positive vapor fraction at initial stage.

rupak504 March 8, 2020 00:41
Quote:
Originally Posted by vinerm (Post 760817)
What's the fraction of vapor at the initialization?
At the initialization the fraction of vapor is zero.





Quote:
Originally Posted by vinerm (Post 760817)
The model requires a positive vapor fraction at initial stage.
Why so?

vinerm March 8, 2020 04:29
EC model Implementation
 
The way the model is implemented, it checks for the minimum value of both phases to determine the mass transfer. If vapor fraction is always zero, the mass transfer will never begin.


All times are GMT -4. The time now is 23:45.