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How to Tackle Evaporation Condensation model of ANSYS Fluent ?? :(

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Old   January 17, 2017, 02:49
Smile How to Tackle Evaporation Condensation model of ANSYS Fluent ?? :(
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vivekanand
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Hello everyone !

Am working on the evaporation of water inside a microchannel using VOF multiphase method enabling Evaporation-Condensation model. Water at its saturated stated is entered through inlet and a heat flux boundary condition is applied to bottom wall, top wall being adiabatic. And outlet is pressure outlet. presently working in a 2D domain.


My problem is, am able to see the occurrence of evaporation because of the change in volume fraction of vapor at outlet but whenever am observing the temperature inside the domain, am finding a temperature higher than the saturation temperature even though the saturated water has not yet fully evaporated.

But as per theory of evaporation, temperature will not change untill the vapor becomes superheated.

Can anyone please tell me how to tackle this problem, why such a high temperature is being witnessed by me even before incomplete evaporation???

Any help regarding this is deeply and warmly welcomed.
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Old   May 21, 2017, 13:19
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Diksha
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Quote:
Originally Posted by nands_bullwalker View Post
Hello everyone !

Am working on the evaporation of water inside a microchannel using VOF multiphase method enabling Evaporation-Condensation model. Water at its saturated stated is entered through inlet and a heat flux boundary condition is applied to bottom wall, top wall being adiabatic. And outlet is pressure outlet. presently working in a 2D domain.


My problem is, am able to see the occurrence of evaporation because of the change in volume fraction of vapor at outlet but whenever am observing the temperature inside the domain, am finding a temperature higher than the saturation temperature even though the saturated water has not yet fully evaporated.

But as per theory of evaporation, temperature will not change untill the vapor becomes superheated.

Can anyone please tell me how to tackle this problem, why such a high temperature is being witnessed by me even before incomplete evaporation???

Any help regarding this is deeply and warmly welcomed.
Hello,
I am also working with VOF and Evaporation-Condensation model. My simulation is diverging and gives unrealistic values of temperature. Do you have any idea why? Please help me if you can. Thank you in advance.
Diksha
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Old   June 3, 2017, 10:00
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Hello Diksha! Sorry for replying late. Can you please elaborate your problem in a bit more self explanatory way dear.
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Old   June 3, 2017, 10:03
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Originally Posted by Diksha View Post
Hello,
I am also working with VOF and Evaporation-Condensation model. My simulation is diverging and gives unrealistic values of temperature. Do you have any idea why? Please help me if you can. Thank you in advance.
Diksha
Hello Diksha! Sorry for replying late. Can you please elaborate your problem in a bit more self explanatory way dear. My email id is "nandu.as.smarty@gmail.com"
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Old   June 4, 2017, 01:01
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Quang Le Dang
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Quote:
Originally Posted by nands_bullwalker View Post
Hello everyone !

Am working on the evaporation of water inside a microchannel using VOF multiphase method enabling Evaporation-Condensation model. Water at its saturated stated is entered through inlet and a heat flux boundary condition is applied to bottom wall, top wall being adiabatic. And outlet is pressure outlet. presently working in a 2D domain.


My problem is, am able to see the occurrence of evaporation because of the change in volume fraction of vapor at outlet but whenever am observing the temperature inside the domain, am finding a temperature higher than the saturation temperature even though the saturated water has not yet fully evaporated.

But as per theory of evaporation, temperature will not change untill the vapor becomes superheated.

Can anyone please tell me how to tackle this problem, why such a high temperature is being witnessed by me even before incomplete evaporation???

Any help regarding this is deeply and warmly welcomed.
The problem probably comes from boiling delay effect which can be controlled by "coeff" in the model. FLUENT always suggests user controlling this coefficient to fit to experiment.

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