Condensation of water vapor to water

visitor · August 17, 2017, 10:39

Got this is error message, I know its a classic to experts. Tried to get out of it but couldn't. Any tips please?

Error in the setting stage.

Equilibrium phase change in one phase in an MPF run is not supported by the solver.

Opaque · August 17, 2017, 14:12

What are you trying to model ?

What approach have you taken ?

visitor · August 19, 2017, 11:47

Have typed, this, hope sufficient to describe set up. Have air with 60 % Relative Humidity crossing a cool coil. Now just want to get the condensation part working. Thanks in advance.
---
Basic Settings> Fluid and Particle Definitions> Vapor. Material selected Water Vapor.

Fluid and Particle Definitions > Water> Material. Material selected Water

Fluid and Particle Definitions > Vapor > Morphology > Option , Continuous Fluid

Fluid and Particle Definitions, For Water
Fluid and Particle Definitions > Water > Morphology > Option, Droplets (Phase Change)

Fluid Models, Multiphase > Homogeneous Model (Selected)

Heat Transfer > Homogeneous Model, not selected.
Heat Transfer > Option , Fluid Dependent

Fluid Specific Models, Fluid, Vapor.
Vapor > Heat Transfer Model > Option , Total Energy,

Fluid, Water

Fluid > Water > Heat Transfer Model > Option, Small Droplet Temperature

Fluid > Water > Nucleation Model, selected.
Fluid > Water > Nucleation Model > Option, Homogeneous

Fluid > Water > Nucleation Model > Nucleation Bulk Tension Factor, selected
Fluid > Water > Nucleation Model > Nucleation Bulk Tension Factor > Nucleation Bulk Tension, as 1

Fluid Pair Models, Fluid Pair, Vapor | Water

Fluid Pair > Vapor | Water > Interphase Transfer > Option, Particle Model

Fluid Pair > Vapor | Water > Mass Transfer > Option, Phase Change

Fluid Pair > Vapor | Water > Mass Transfer > Phase Change Model > Option, Small Droplets

Fluid Pair > Vapor | Water > Heat Transfer > Option, Small Droplets Boundary Details

Heat Transfer > Option, Fluid Dependent

Boundary Conditions > Vapor > Heat Transfer > Option, Total Temperature, 300K

Vapor > Volume Fraction > Option, Value of 0.5 entered (will fix this later for 60 % RH)

Boundary Conditions > Water > Volume Fraction > Option, 0.5 ….

Boundary Conditions > Water > Droplet Number > Option, Specified Number a

Boundary Conditions > Water > Droplet Number > Droplet Number, 0 [m^-3], Not Specified Diameter.

visitor · August 23, 2017, 04:37

Any suggestions, please?

By the way it has been sometime, the water vapor was Water Vapor Ideal Gas as far as I remember. As in software material database.

The humid air will pass over a cooler wall, and condensation should occur.

ghorrocks · August 23, 2017, 07:05

This FAQ may help: https://www.cfd-online.com/Wiki/Ansy...ible_answer.3F

If you are getting no response then your original question was probably not asked very well.

visitor · August 23, 2017, 10:19

Sorry if I did not make it clear, I have actually worked on this over a year ago. Just curious what the answer is.

All it is, humid air with 60% 24 C relative humidity going over a cold coil. Classic air-conditioning example. What I prepared at the time is what I have shown at the top.

Need to see condensation. Above method I have tried relies on nucleation of condensate. Vapor to drops of water.

ghorrocks · August 23, 2017, 19:50

Multiphase flow with phase change is a difficult topic, I trust you are an experienced CFD user if you are going to do a simulation like that. Have you looked at the tutorial examples available on the ANSYS customer site? If that does not have tutorial examples then try contacting CFX support as they have lots more examples.

soumitra2102 · June 7, 2019, 19:25

If it’s a case of condensation WITHOUT presence of any non-condemnable gases, how about using multi-component homogeneous binary mixture only ?

August 17, 2017, 10:39	Condensation of water vapor to water	#1
visitor Senior Member AH Join Date: Apr 2014 Posts: 287 Rep Power: 0	Got this is error message, I know its a classic to experts. Tried to get out of it but couldn't. Any tips please? Error in the setting stage. Equilibrium phase change in one phase in an MPF run is not supported by the solver.

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August 17, 2017, 14:12		#2
Opaque Senior Member Join Date: Jun 2009 Posts: 1,880 Rep Power: 33	What are you trying to model ? What approach have you taken ?

August 19, 2017, 11:47		#3
visitor Senior Member AH Join Date: Apr 2014 Posts: 287 Rep Power: 0	Have typed, this, hope sufficient to describe set up. Have air with 60 % Relative Humidity crossing a cool coil. Now just want to get the condensation part working. Thanks in advance. --- Basic Settings> Fluid and Particle Definitions> Vapor. Material selected Water Vapor. Fluid and Particle Definitions > Water> Material. Material selected Water Fluid and Particle Definitions > Vapor > Morphology > Option , Continuous Fluid Fluid and Particle Definitions, For Water Fluid and Particle Definitions > Water > Morphology > Option, Droplets (Phase Change) Fluid Models, Multiphase > Homogeneous Model (Selected) Heat Transfer > Homogeneous Model, not selected. Heat Transfer > Option , Fluid Dependent Fluid Specific Models, Fluid, Vapor. Vapor > Heat Transfer Model > Option , Total Energy, Fluid, Water Fluid > Water > Heat Transfer Model > Option, Small Droplet Temperature Fluid > Water > Nucleation Model, selected. Fluid > Water > Nucleation Model > Option, Homogeneous Fluid > Water > Nucleation Model > Nucleation Bulk Tension Factor, selected Fluid > Water > Nucleation Model > Nucleation Bulk Tension Factor > Nucleation Bulk Tension, as 1 Fluid Pair Models, Fluid Pair, Vapor \| Water Fluid Pair > Vapor \| Water > Interphase Transfer > Option, Particle Model Fluid Pair > Vapor \| Water > Mass Transfer > Option, Phase Change Fluid Pair > Vapor \| Water > Mass Transfer > Phase Change Model > Option, Small Droplets Fluid Pair > Vapor \| Water > Heat Transfer > Option, Small Droplets Boundary Details Heat Transfer > Option, Fluid Dependent Boundary Conditions > Vapor > Heat Transfer > Option, Total Temperature, 300K Vapor > Volume Fraction > Option, Value of 0.5 entered (will fix this later for 60 % RH) Boundary Conditions > Water > Volume Fraction > Option, 0.5 …. Boundary Conditions > Water > Droplet Number > Option, Specified Number a Boundary Conditions > Water > Droplet Number > Droplet Number, 0 [m^-3], Not Specified Diameter.

August 23, 2017, 04:37		#4
visitor Senior Member AH Join Date: Apr 2014 Posts: 287 Rep Power: 0	Any suggestions, please? By the way it has been sometime, the water vapor was Water Vapor Ideal Gas as far as I remember. As in software material database. The humid air will pass over a cooler wall, and condensation should occur.

August 23, 2017, 07:05		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	This FAQ may help: https://www.cfd-online.com/Wiki/Ansy...ible_answer.3F If you are getting no response then your original question was probably not asked very well.

August 23, 2017, 10:19		#6
visitor Senior Member AH Join Date: Apr 2014 Posts: 287 Rep Power: 0	Sorry if I did not make it clear, I have actually worked on this over a year ago. Just curious what the answer is. All it is, humid air with 60% 24 C relative humidity going over a cold coil. Classic air-conditioning example. What I prepared at the time is what I have shown at the top. Need to see condensation. Above method I have tried relies on nucleation of condensate. Vapor to drops of water.

August 23, 2017, 19:50		#7
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	Multiphase flow with phase change is a difficult topic, I trust you are an experienced CFD user if you are going to do a simulation like that. Have you looked at the tutorial examples available on the ANSYS customer site? If that does not have tutorial examples then try contacting CFX support as they have lots more examples.

June 7, 2019, 19:25		#8
soumitra2102 Member Soumitra Vadnerkar Join Date: Aug 2018 Posts: 70 Rep Power: 8	If it’s a case of condensation WITHOUT presence of any non-condemnable gases, how about using multi-component homogeneous binary mixture only ?