simulating two phase heat and mass transfer inside two phase closed thermosyphon.

1757003@kiit.ac.in · October 31, 2018, 05:45

I'm simulating two phase heat and mass transfer inside two phase closed thermosyphon using VOF model in 2-D axysymmetric rectangular geometry.I've further splitted the geometry into three parts using ANSYS SPACE CLAIM. Can someone help me with the next steps to follow?

vivek162 · November 9, 2018, 18:49

what type of help do you need?

1757003@kiit.ac.in · November 10, 2018, 05:25

vivek162,i'm simulating a paper https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&u act=8&ved=2ahUKEwix8fezv8neAhVVknAKHZS7AXIQFjAAegQ ICBAC&url=https%3A%2F%2Fwww.researchgate.net%2Fpro file%2FAbdelhamid_Kassem%2Fpost%2FHow_do_I_simulat e_condenser_section_heat_pipe%2Fattachment%2F59d64 0bb79197b807799ce1e%2FAS%253A431955293544449%25401 479997575885%2Fdownload%2FNumerical%2Bmodelling%2B of%2Bthe%2Btemperature%2Bdistribution%2Bin%2Ba%2Bt wo-phase%2528Autosaved%2529.pdf&usg=AOvVaw3u0rPdu3PQu wkaJIqX9E1O using ANSYS 19.0 student version.In the paper ,saturation temperature is 373 k inside the thermosyphon,but there is no mention of saturation presssure.What is the pressure inside the pipe,also can i take steady state instead of tansient.In that case,what will be the impact?

vivek162 · November 10, 2018, 15:45

I have simulated the same model. "The VOF formulation in ANSYS Fluent is generally used to compute a time-dependent solution". it is better to go with a transient.
Particularly for the same paper, they have used operating pressure 101325 Pa. if you want to change the operating you have to look for the respective saturation temperature of water ( It will be lower than the 373 K depends on operating pressure). if I am not wrong then you have asked the same question on Ansys student community I have mentioned there about the standard state enthalpy if you will take the wrong value, you will phase the problem of Global courant no. error ( same for the time-step you have to chose the correct time-step). Try that if you will face any problem let me know.
Moreover, if you have set a saturation temperature of 373 K. then initialize your case at 373.1 K slightly higher than the saturation temperature to save the computational time.

1757003@kiit.ac.in · November 22, 2018, 02:23

sir,can you give me your mail address so that i can discuss with you the steps,i am following.

vivek162 · November 25, 2018, 15:21

vvk.pawar7@gmail.com

1757003@kiit.ac.in · March 2, 2019, 05:39

how far result will be affected when using implicit scheme instead of explicit scheme in simulation of two phase closed thermosyphon?

vivek162 · March 16, 2019, 14:51

This link might help you to understand the difference between implicit and explicit scheme

https://www.flow3d.com/resources/cfd...rical-methods/

October 31, 2018, 05:45	simulating two phase heat and mass transfer inside two phase closed thermosyphon.	#1
1757003@kiit.ac.in New Member PRASHANT KUMAR JHA Join Date: Sep 2018 Posts: 8 Rep Power: 8	I'm simulating two phase heat and mass transfer inside two phase closed thermosyphon using VOF model in 2-D axysymmetric rectangular geometry.I've further splitted the geometry into three parts using ANSYS SPACE CLAIM. Can someone help me with the next steps to follow?

November 10, 2018, 15:45		#4
vivek162 New Member vivek Join Date: Aug 2018 Posts: 14 Rep Power: 8	I have simulated the same model. "The VOF formulation in ANSYS Fluent is generally used to compute a time-dependent solution". it is better to go with a transient. Particularly for the same paper, they have used operating pressure 101325 Pa. if you want to change the operating you have to look for the respective saturation temperature of water ( It will be lower than the 373 K depends on operating pressure). if I am not wrong then you have asked the same question on Ansys student community I have mentioned there about the standard state enthalpy if you will take the wrong value, you will phase the problem of Global courant no. error ( same for the time-step you have to chose the correct time-step). Try that if you will face any problem let me know. Moreover, if you have set a saturation temperature of 373 K. then initialize your case at 373.1 K slightly higher than the saturation temperature to save the computational time. msp.16191@gmail.com likes this.

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November 9, 2018, 18:49		#2
vivek162 New Member vivek Join Date: Aug 2018 Posts: 14 Rep Power: 8	what type of help do you need?

November 10, 2018, 05:25		#3
1757003@kiit.ac.in New Member PRASHANT KUMAR JHA Join Date: Sep 2018 Posts: 8 Rep Power: 8	vivek162,i'm simulating a paper https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&u act=8&ved=2ahUKEwix8fezv8neAhVVknAKHZS7AXIQFjAAegQ ICBAC&url=https%3A%2F%2Fwww.researchgate.net%2Fpro file%2FAbdelhamid_Kassem%2Fpost%2FHow_do_I_simulat e_condenser_section_heat_pipe%2Fattachment%2F59d64 0bb79197b807799ce1e%2FAS%253A431955293544449%25401 479997575885%2Fdownload%2FNumerical%2Bmodelling%2B of%2Bthe%2Btemperature%2Bdistribution%2Bin%2Ba%2Bt wo-phase%2528Autosaved%2529.pdf&usg=AOvVaw3u0rPdu3PQu wkaJIqX9E1O using ANSYS 19.0 student version.In the paper ,saturation temperature is 373 k inside the thermosyphon,but there is no mention of saturation presssure.What is the pressure inside the pipe,also can i take steady state instead of tansient.In that case,what will be the impact?

November 22, 2018, 02:23		#5
1757003@kiit.ac.in New Member PRASHANT KUMAR JHA Join Date: Sep 2018 Posts: 8 Rep Power: 8	sir,can you give me your mail address so that i can discuss with you the steps,i am following.

November 25, 2018, 15:21		#6
vivek162 New Member vivek Join Date: Aug 2018 Posts: 14 Rep Power: 8	vvk.pawar7@gmail.com

March 2, 2019, 05:39		#7
1757003@kiit.ac.in New Member PRASHANT KUMAR JHA Join Date: Sep 2018 Posts: 8 Rep Power: 8	how far result will be affected when using implicit scheme instead of explicit scheme in simulation of two phase closed thermosyphon?

March 16, 2019, 14:51		#8
vivek162 New Member vivek Join Date: Aug 2018 Posts: 14 Rep Power: 8	This link might help you to understand the difference between implicit and explicit scheme https://www.flow3d.com/resources/cfd...rical-methods/