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Heat transfer simulation result is much larger than experimental result

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I modelled the heat transfer through a hollow brick to calculate the equivalent thermal conductivity. So general heat transfer and weakly compressible Navier-Stokes modules were taken to build the model. But the simulation result is a little larger than the value obtained from experiments. The result of simulation is 0.91 w/(km), while experimental result is 0.68 w/(km).

I consider there should be some problems with my model (probably convection), but I can't find it. The simulation is successful, no error messages. So what could be the problem causing the big difference between computational result and experimental result?

Can anyone please help me?

Thanks in advance
Xiqi


3 Replies Last Post Dec 5, 2012, 1:44 a.m. EST

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Posted: 1 decade ago Sep 2, 2012, 7:58 p.m. EDT
For the convection, bousinesq approximation was applied in the model, namely volume force=g*beta*rho*(T0-T). However, after I change the value of T0, the velocity of convection didn't change. What's the problem?

For the convection, bousinesq approximation was applied in the model, namely volume force=g*beta*rho*(T0-T). However, after I change the value of T0, the velocity of convection didn't change. What's the problem?

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Posted: 1 decade ago Dec 3, 2012, 12:24 p.m. EST
If you have found a solution for this problem, I am very interested. COMSOL also overestimates results tested experimentally.
If you have found a solution for this problem, I am very interested. COMSOL also overestimates results tested experimentally.

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Dec 5, 2012, 1:44 a.m. EST
Hi

if your model and measurements disagree, which parameters should you adapt to get them closer ? This could tell what is wrong, if it's not just a mesh issue, in HT fluid solid the mesh is terribly important and makes easily >>100% errors

--
Good luck
Ivar
Hi if your model and measurements disagree, which parameters should you adapt to get them closer ? This could tell what is wrong, if it's not just a mesh issue, in HT fluid solid the mesh is terribly important and makes easily >>100% errors -- Good luck Ivar

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