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heat source setting

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HI;I have a question that when I using heat transfer in solid and lamina flow model to simulate heating a crucible in a silicon furnace, when I setting the heat souce desity equal:6000W/m^3, the simulation is coveraged, The mamxium temperature is 1400K, but when the value is 20000W/m^3, the simumation divergenced. pls help me! How can I solve this question.Thanks.

2 Replies Last Post 3 feb 2013, 19:13 GMT-5
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 2 feb 2013, 09:33 GMT-5
Hi

are you in steady state, or transient ? and which physics exactly NITF, HT, ...

One issue one can easily get with dissusion equations is that, in transient studies particularly, the gradients from the initial conditions are very steep, and the mesh being used is not compatible (too coarse in certain regions).

If you are in stationary, what you can ry is to ramp up the power with a solver - contianuation tab - prametrical sweep case and increase the power in 5-10 steps, then each solver case is using the previous results as starting point, and often this allows you to reach your max flux values

--
Good luck
Ivar
Hi are you in steady state, or transient ? and which physics exactly NITF, HT, ... One issue one can easily get with dissusion equations is that, in transient studies particularly, the gradients from the initial conditions are very steep, and the mesh being used is not compatible (too coarse in certain regions). If you are in stationary, what you can ry is to ramp up the power with a solver - contianuation tab - prametrical sweep case and increase the power in 5-10 steps, then each solver case is using the previous results as starting point, and often this allows you to reach your max flux values -- Good luck Ivar

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Posted: 1 decade ago 3 feb 2013, 19:13 GMT-5
The problem had been sovled.Thank very much!
The problem had been sovled.Thank very much!

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