CFD and Salt bath modelling

faisal_durr · February 1, 2012, 08:25

Hello. I am trying to mimic a salt bath modelling for a natural ventilation case in CFD. It is actually a box with water in it as ambient fluid with brine being introduced to produce a "heat source" inside through a nozzle. The plume is however turbulent. Could you please advise me on how to do this CFX pre? I have the density of the brine water and also the mass flow rate in cm^3/minute. I have tried doing this by the 'source point' but dont know what to put in the fields. You see it asks for velocity while I dont want to have a forced plume. Also it wants the turbulent kinetic energy. I want these kinda things to develop on their own. Can you please help? Thank you.

Regards,
Faisal.

ghorrocks · February 1, 2012, 17:37

If that is the case then you better model the plume nozzle so you can get the correct jet and mixing, which will lead to turbulence generation. The whole idea of the source point approach is that these things are known so fluid can be simply generated with these properties, and if they are not known then it is not suitable.

faisal_durr · February 3, 2012, 06:27

Hi, thank you. Suppose I have a salt bath model and I create the same scale model in CFD. Now for the salt bath model I will obviously introduce brine through a nozzle to create a plume (to mimic heat source). Now instead of creating a brine source in the CFD model I wana use a heat source by defining an area with a heat flux in Watts or W/m^2. Suppose the areas of the nozzle opening area in the SBM and the heat source are in the CFD model are the same. How do I calculate how much heat flux to put in my CFD model in watts or W/m^2? If you guys could help me with this one I would really be thankful. Thank you.

ghorrocks · February 5, 2012, 17:15

We cannot answer that, it is defined by your system. What is the flow rate, what is the temeprature? That defines the heat source.

faisal_durr · February 6, 2012, 04:58

The flow rate in the salt bath model through the nozzle is 100cm^3/minute while the ambient temperature of water is 20C.

February 1, 2012, 08:25	CFD and Salt bath modelling	#1
faisal_durr Member Faisal Durrani Join Date: Nov 2009 Location: England Posts: 62 Rep Power: 16	Hello. I am trying to mimic a salt bath modelling for a natural ventilation case in CFD. It is actually a box with water in it as ambient fluid with brine being introduced to produce a "heat source" inside through a nozzle. The plume is however turbulent. Could you please advise me on how to do this CFX pre? I have the density of the brine water and also the mass flow rate in cm^3/minute. I have tried doing this by the 'source point' but dont know what to put in the fields. You see it asks for velocity while I dont want to have a forced plume. Also it wants the turbulent kinetic energy. I want these kinda things to develop on their own. Can you please help? Thank you. Regards, Faisal.

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February 1, 2012, 17:37		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	If that is the case then you better model the plume nozzle so you can get the correct jet and mixing, which will lead to turbulence generation. The whole idea of the source point approach is that these things are known so fluid can be simply generated with these properties, and if they are not known then it is not suitable.

February 3, 2012, 06:27		#3
faisal_durr Member Faisal Durrani Join Date: Nov 2009 Location: England Posts: 62 Rep Power: 16	Hi, thank you. Suppose I have a salt bath model and I create the same scale model in CFD. Now for the salt bath model I will obviously introduce brine through a nozzle to create a plume (to mimic heat source). Now instead of creating a brine source in the CFD model I wana use a heat source by defining an area with a heat flux in Watts or W/m^2. Suppose the areas of the nozzle opening area in the SBM and the heat source are in the CFD model are the same. How do I calculate how much heat flux to put in my CFD model in watts or W/m^2? If you guys could help me with this one I would really be thankful. Thank you.

February 5, 2012, 17:15		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	We cannot answer that, it is defined by your system. What is the flow rate, what is the temeprature? That defines the heat source.

February 6, 2012, 04:58		#5
faisal_durr Member Faisal Durrani Join Date: Nov 2009 Location: England Posts: 62 Rep Power: 16	The flow rate in the salt bath model through the nozzle is 100cm^3/minute while the ambient temperature of water is 20C.