Learning Forum

[kaushal.21910939]

Hello everyone,

I am trying to find out the time required for fluid to cooldown. Please consider following elaboration.

 

1. A fluid having temperature of 350 DegC is standing in the tube assembly as shown in the image. (There are valves on the both ends holding the fluid in the tube).
2. The tube assembly is exposed to an ambient temperature of 22 DegC for certain amout of time.
3. I want to find out the amount of time required for that fluid inside the assembly to go down to 150 DegC from 350 DegC.
4. What type of analysis and boundary conditions shall I prefer?

[Nikhil Narale]

Hello, 

 

Here are few settings that came to my mind:

• Turn on gravity and define fluid density variation for modeling buoyancy effect (Just in case if you want to model the effect of change in density with temperature and the buoyancy effect) 
• Assign solid material properties (density, k, cp)
• Use coupled wall (CHT) between fluid and solid. I would recommend to share the faces at the CAD/Meshing stage (share topology)
• Apply either constant temperature (which should be different from the ambient temperature ; you will have to consider convective resistance) or convection boundary condition on outer tube walls with appropriate htc and ambient temperature of 22 DegC.
• Initialize (patch) fluid temperature at 350°C
• Choose a suitable time step size and number of time steps (ball park figure for now) and start the simulation, monitoring the time and the fluid temperature. 

 

Thanks!

Nikhil