[RAJ KIRAN]

I am working on my Master thesis. My goal is to simulate condensation in a horizontal pipe (Stratified flow) using fluent. I am using VOF method. I am using a different condensation model so I need to write a UDF for mass transfer. From what I have understood after reading manual, I can use either DEFINE_MASS_TRANSFER or DEFINE_SOURCE Macros.

--If i use MASS_TRANSFER macro, How will fluent interpret this macro? Will it automatically calculate the source terms for volume fraction equation and energy equation? If it does, How will it calculate?

--If i use DEFINE_SOURCE macro, Should I add source terms for both liquid and steam phases? Is this compulsory because volume fraction equation is solved only for secondoray phase.

Thanks in advance

[MDSHUJAN]

Originally Posted by RAJ KIRAN

I am working on my Master thesis. My goal is to simulate condensation in a horizontal pipe (Stratified flow) using fluent. I am using VOF method. I am using a different condensation model so I need to write a UDF for mass transfer. From what I have understood after reading manual, I can use either DEFINE_MASS_TRANSFER or DEFINE_SOURCE Macros.

--If i use MASS_TRANSFER macro, How will fluent interpret this macro? Will it automatically calculate the source terms for volume fraction equation and energy equation? If it does, How will it calculate?

--If i use DEFINE_SOURCE macro, Should I add source terms for both liquid and steam phases? Is this compulsory because volume fraction equation is solved only for secondoray phase.

Thanks in advance

You need to add source for both phase. There is a Tutorial from ANSYS FLUENT named horizontal film evaporation. Try to read it. Adding only 1 source will increase or decrease total mass of the system.

[RAJ KIRAN]

Thanks for the reply,

I figured it out

Regards,
Rajukiran

[MDSHUJAN]

Originally Posted by RAJ KIRAN

Thanks for the reply,

I figured it out

Regards,
Rajukiran

Hi Kiran. Did you get condensation from your simulation? I am trying to simulate Loop Heat Pipe, I got evaporation, but no condensation.

If you got condensation, I will want to look at your udf, or what model you use? I am using Lee model.

[RAJ KIRAN]

yes,

I am not using Lee model. I used condensation model which is based on surface renewal theory.

[SACHIN1639]

raj kiran sir can you please send me your ufd code?i am trying to wright the code from last30 days please help me?
sachin1639@gmail.com

[RAJ KIRAN]

Originally Posted by SACHIN1639

raj kiran sir can you please send me your ufd code?i am trying to wright the code from last30 days please help me?
sachin1639@gmail.com

Sorry, I can't send it to you, because I did it for a company as part of my thesis, However you can ask me questions and I can help you as much as I can.