Refrigerant R134a Phase Change

Mahesh Bondhu · April 22, 2013, 06:14

Hi,
I am new to Phase change simulation.
Currently i am simulating the evaporation of R134a Refrigerant at constant temperature, I have used the Evaporation and condensation model which is available in Ansys 14.0 . I am not understanding how the model is working. I have few doubts on this model

1. How can we maintain the constant temperature during phase change
2. What is the evaporation frequency i.e 0.1., in Ansys 14. 0 model.
3. How can we define material properties of liquid and vapor
i have defined material properties of liquid and vapor standard state enthalpies in the following manner
liquid 213,58 kj/kg vapor 404.32 kj/kg reference temperature 298.15 K for liquid and vapor.

can any one help me .......how to proceed and how to define material properties.

4. Whether available Evaporation-Condensation model suitable or not, for phase change application in refrigeration
5. What is the backflow volume fraction at outlet.

Please help me

Khaled yousef · April 24, 2013, 13:05

I Face the same problem but for R410A

Mahesh Bondhu · April 26, 2013, 07:18

Yousef,

Can you tell how to load the real gas models in Fluent. I have followed the Procedure which was given in Ansys text commands. Its showing invalid commands
>define/user-defined/real-gas-models/nist-real-gas-models

Please help me

amit112amit · May 2, 2013, 02:57

You must be having an older version of Fluent. I have used the command and it works in Ansys 13 which has Fluent 13. I have also tried to use it in Fluent 6.2 and it said "Invalid command".

athonyburk · May 4, 2013, 09:13

You can find some details about the Evaporation-Condensation Model in the following URL:
https://www.sharcnet.ca/Software/Flu...th/node344.htm

I don't think you need to define standard state enthalpies since you might not expect chemical reactions to occur.

By the way, what multiphase model do you use?

April 22, 2013, 06:14	Refrigerant R134a Phase Change	#1
Mahesh Bondhu New Member Mahesh Join Date: Apr 2013 Posts: 2 Rep Power: 0	Hi, I am new to Phase change simulation. Currently i am simulating the evaporation of R134a Refrigerant at constant temperature, I have used the Evaporation and condensation model which is available in Ansys 14.0 . I am not understanding how the model is working. I have few doubts on this model 1. How can we maintain the constant temperature during phase change 2. What is the evaporation frequency i.e 0.1., in Ansys 14. 0 model. 3. How can we define material properties of liquid and vapor i have defined material properties of liquid and vapor standard state enthalpies in the following manner liquid 213,58 kj/kg vapor 404.32 kj/kg reference temperature 298.15 K for liquid and vapor. can any one help me .......how to proceed and how to define material properties. 4. Whether available Evaporation-Condensation model suitable or not, for phase change application in refrigeration 5. What is the backflow volume fraction at outlet. Please help me

April 24, 2013, 13:05	I Face the same problem but for R410A	#2
Khaled yousef New Member khaled yousef Join Date: Apr 2013 Posts: 8 Rep Power: 13	I Face the same problem but for R410A

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April 26, 2013, 07:18		#3
Mahesh Bondhu New Member Mahesh Join Date: Apr 2013 Posts: 2 Rep Power: 0	Yousef, Can you tell how to load the real gas models in Fluent. I have followed the Procedure which was given in Ansys text commands. Its showing invalid commands >define/user-defined/real-gas-models/nist-real-gas-models Please help me

May 2, 2013, 02:57		#4
amit112amit New Member Amit Singh Join Date: Feb 2013 Posts: 4 Rep Power: 13	You must be having an older version of Fluent. I have used the command and it works in Ansys 13 which has Fluent 13. I have also tried to use it in Fluent 6.2 and it said "Invalid command".

May 4, 2013, 09:13		#5
athonyburk New Member Join Date: Apr 2013 Posts: 11 Rep Power: 13	You can find some details about the Evaporation-Condensation Model in the following URL: https://www.sharcnet.ca/Software/Flu...th/node344.htm I don't think you need to define standard state enthalpies since you might not expect chemical reactions to occur. By the way, what multiphase model do you use?