Heat transfer in the reactor pressure vessel

motahar · August 2, 2010, 14:13

Hi friends,

I'm simulating a RPV (reactor pressure vessel). When passing the coolant through the fuel assemblies, the coolant takes the heat from the fuel assemblies. The boundary condition I define for fuel assemblies in CFX-pre is the heat flux. Even though I insert the maximum heat flux for the fuel assemblies, the coolant warms just a few degrees, in the case that it has to be heated about 32 degrees.

I don't know what's the matter???
Can any friend help me about this problem???

I urgently need your help!!!

ghorrocks · August 2, 2010, 19:52

Obviously your heat transfer model is very inaccurate. Assuming you have the physics of the simulation set up correctly, have you checked your mesh resolution? Convergence? Time step size (if transient)? Y+?

motahar · August 3, 2010, 05:04

I have changed the time step many times, but the results were the same.
I also changed the number of mesh elements without gaining a good result.

I haven't worked on the mesh resolution a lot.
I think I have to work on it more.

Thanks for your help ghorrocks.

August 2, 2010, 14:13	Heat transfer in the reactor pressure vessel	#1
motahar New Member M. A. Join Date: Jul 2010 Posts: 27 Rep Power: 16	Hi friends, I'm simulating a RPV (reactor pressure vessel). When passing the coolant through the fuel assemblies, the coolant takes the heat from the fuel assemblies. The boundary condition I define for fuel assemblies in CFX-pre is the heat flux. Even though I insert the maximum heat flux for the fuel assemblies, the coolant warms just a few degrees, in the case that it has to be heated about 32 degrees. I don't know what's the matter??? Can any friend help me about this problem??? I urgently need your help!!!

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August 2, 2010, 19:52		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Obviously your heat transfer model is very inaccurate. Assuming you have the physics of the simulation set up correctly, have you checked your mesh resolution? Convergence? Time step size (if transient)? Y+?

August 3, 2010, 05:04		#3
motahar New Member M. A. Join Date: Jul 2010 Posts: 27 Rep Power: 16	I have changed the time step many times, but the results were the same. I also changed the number of mesh elements without gaining a good result. I haven't worked on the mesh resolution a lot. I think I have to work on it more. Thanks for your help ghorrocks.