buoyancyPimpleFoam surface temperature set-up

foamingMouth · February 14, 2017, 14:34

Hi,

I'm using buoyancyPimpleFoam to model heat-driven flows off a hot mass.

Let's say my hot mass is cylindrical and there is insulation around the sides (but not at the top or bottom) with a narrow gap between the hot mass and the insulation material. I need to work out how fast the flow through that gap will get if natural convection prevails.

Using a basic model I have got it working if the temperature delta between the air and the hot mass is 100K, but my temperature delta is closer to 600K. When I put the real value of temperature into the 0/T set-up file for the hot mass I cannot control my courant number and foam aborts.

I've dropped my timestep in controlDict to 5e-5, with no luck.

Q: Is there any way to heat my mass up during the simulation so that it doesn't go through the initial shock?

Thanks in advance...

alexeym · February 14, 2017, 16:20

Hi,

Use SemiImplicitSource? You can find description in $FOAM_SRC/fvOptions/sources/general/semiImplicitSource/SemiImplicitSource.H. In your case this source should have type scalar, field should be T, you can use only explicit part.

February 14, 2017, 14:34	buoyancyPimpleFoam surface temperature set-up	#1
foamingMouth New Member Sharon Join Date: Sep 2016 Posts: 4 Rep Power: 10	Hi, I'm using buoyancyPimpleFoam to model heat-driven flows off a hot mass. Let's say my hot mass is cylindrical and there is insulation around the sides (but not at the top or bottom) with a narrow gap between the hot mass and the insulation material. I need to work out how fast the flow through that gap will get if natural convection prevails. Using a basic model I have got it working if the temperature delta between the air and the hot mass is 100K, but my temperature delta is closer to 600K. When I put the real value of temperature into the 0/T set-up file for the hot mass I cannot control my courant number and foam aborts. I've dropped my timestep in controlDict to 5e-5, with no luck. Q: Is there any way to heat my mass up during the simulation so that it doesn't go through the initial shock? Thanks in advance...

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February 14, 2017, 16:20		#2
alexeym Senior Member Alexey Matveichev Join Date: Aug 2011 Location: Nancy, France Posts: 1,938 Rep Power: 39	Hi, Use SemiImplicitSource? You can find description in $FOAM_SRC/fvOptions/sources/general/semiImplicitSource/SemiImplicitSource.H. In your case this source should have type scalar, field should be T, you can use only explicit part.