Hi,
I am just having some trouble modelling a radiator.
For some reason the simulation indicates that the system can cool from inlet to outlet about 30 degrees; however, in real-life testing the actual system achieved a factor of ten less!
I have set the materials aluminium 6061 casing and water coolant, assigned inlet conditions as 15l/min at 75 degrees, outlet conditions as atmospheric pressure and then put a flow coefficient of 0.024 to model ambient air at a ref temperature of 20 degrees.
In fact, sometimes the simulation gives next to no thermal properties of the system.
What can I do?
Also, if I wanted to put an external airflow through the fins whilst keeping the internal coolant flow how would I go about doing it?
Thanks
Solved! Go to Solution.
Solved by Jon.Wilde. Go to Solution.
Solved by Jon.Wilde. Go to Solution.
You have applied your film coefficient on both the internal and external walls. It should only be on the external walls.
The easiest way to do that on your model:
I would try this and see how your analysis results look before putting air flow through the radiator fins. One other thing to consider is running to full convergence (more than 100 iterations are typically required).
Hope this helps.
Take a look in the help guide or google.
For typical values, we would use something like 5W/m2/K at ambient temp with just naturally convected air externally. This value might increase to 20 for forced convection, it is an assumption though.
To model the external air, just extrude a cuboid on either side of the radiator, in-line with the fins. This will be your cool air with a flow rate and temp on one side and a P=0 on the other.
No problem.
If it matches test, I'd say you are OK. although your mesh did look pretty coarse. 4-5 elements through a gap is recommended.
Regarding the 2 fluids touching, just model it so that they do not. Maybe focus the inlet just on the tubes, or add a cap on the coolant which you can supress from the mesh (essentially leaving a hole in the model) where you can apply the flow rate.
Would you like to share an image of what you have?
Okay I will have a look into it!
I have attached what I did, it isn't pretty though!
Thanks for sharing. I know you are already making changes but there are a few things to mention here:
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