phase change

sxl_sxl · January 2, 2018, 10:00

Hello everyone:
floefd16 new features:
Real gases with phase change, like refrigerants, etc.
Help introduce phase transition function is very little, I understand the dissolved gas quality component is dry, but its value range is not between 0 ~ 1.
Also want to know the use of phase change function.
Can anyone provide a tutorial on this feature?
thank you all

Boris_M · January 8, 2018, 06:55

Hello Sun,

What CAD version are you using? I need to check if I have a model for that CAD system.
Yes, unfortunately there is little information on the phase change capabilities with real gasses. I myself haven't worked with it yet as there are not that many applications that came across my table since V16.
There is a small trick that was necessary back then when it was still a beta. You should use a small admixture of adding also Air with a mass fraction of 0.0001 or some more to the refrigerant. This makes the solver stable and might be a reason for the crash you have. I don't know if this is still necessary but you can try if that helps.

Two other things help as well.
You should specify only one phase at the inlet so not a transitional condition but either a condition where the refrigerant is either liquid or gas.
The other thing is to keep the initial conditions the same as the conditions at the inlet.

If there is a "hard" phase transition you might need to increase the mass fraction of the ideal gas component some more.

Regards,
Boris

sxl_sxl · January 8, 2018, 07:48

Hello Boris_M
I am using FloEFD.17.0.Stabdalone
Thank you for your reply, I will continue to try to follow your suggestions, and then feedback.
Thank you
Regards,
SUN

January 2, 2018, 10:00	phase change	#1
sxl_sxl New Member SUN Join Date: Jan 2018 Posts: 7 Rep Power: 8	Hello everyone: floefd16 new features: Real gases with phase change, like refrigerants, etc. Help introduce phase transition function is very little, I understand the dissolved gas quality component is dry, but its value range is not between 0 ~ 1. Also want to know the use of phase change function. Can anyone provide a tutorial on this feature? thank you all

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Multiphase solvers and non-isothermal phase change	erlend_grotle	OpenFOAM	1	September 25, 2021 09:48
Need help regarding phase change models in ansys fluent	diggee	Fluent Multiphase	0	October 11, 2016 11:35
Change phase phenomena	Imane	FLUENT	0	May 4, 2016 15:56
Two phase flow with phase change	Ahmad Al-Zoubi	CFX	1	November 26, 2008 03:59
How to model the solid-fluid phase change in CFX	ohrmond	CFX	2	May 26, 2006 06:27

January 8, 2018, 06:55		#2
Boris_M Disabled Join Date: Jul 2009 Posts: 616 Rep Power: 23	Hello Sun, What CAD version are you using? I need to check if I have a model for that CAD system. Yes, unfortunately there is little information on the phase change capabilities with real gasses. I myself haven't worked with it yet as there are not that many applications that came across my table since V16. There is a small trick that was necessary back then when it was still a beta. You should use a small admixture of adding also Air with a mass fraction of 0.0001 or some more to the refrigerant. This makes the solver stable and might be a reason for the crash you have. I don't know if this is still necessary but you can try if that helps. Two other things help as well. You should specify only one phase at the inlet so not a transitional condition but either a condition where the refrigerant is either liquid or gas. The other thing is to keep the initial conditions the same as the conditions at the inlet. If there is a "hard" phase transition you might need to increase the mass fraction of the ideal gas component some more. Regards, Boris

January 8, 2018, 07:48		#3
sxl_sxl New Member SUN Join Date: Jan 2018 Posts: 7 Rep Power: 8	Hello Boris_M I am using FloEFD.17.0.Stabdalone Thank you for your reply, I will continue to try to follow your suggestions, and then feedback. Thank you Regards, SUN