forum.semcad.com

hi
I start to work with thermal solver ,and I have many questions ,I appreciate it if you can help me :
1.when I put the antenna near the head, How can I control the heat exchange between the brain tissues, here I assumed that the air is consider as a cooling system.

2.what isthe effect of heat flux value?if I put it zero ,is it affect the thermal results?

3.When I start the thermal simulation the following warning is appear floating point precision might be insufficient).I increase the time steps and used double precision solver, but still there is the same warning. How can I solve this problem?

4.How can I represent the movement (flow) of the liquids in thermal solver?

Hi,

You are not the 1st one to ask these questions (and I am pretty sure not the last)
So I will try to be clear here:







1)First of all you should not confuse boundary conditions with thermal conduction. Thermal energy is transferred through cells by the thermal conduction mechanism. This is of course handled by the bioheat equation so as long as you set the thermal parameters of the various tissues correctly (through the material database) heat exchange through conduction is taken into account

2)Secondly the exchange of heat energy can be defined by the boundary conditions. So answers to questions like:
a)How to treat air sockets, or the air/background around the body
b)How to treat flowing liquids like blood
c)How to set up thermal boundary conditions e.t.c.
have been asked before and you can find a pretty informative thread here:

http://forum.semcad.com/viewtopic.php?f=13&t=189

(specifically in the 2nd post of the above thread)



1)Although this warning comes up you should only pay attention to it when you are using the 'Steady State' thermal solver included in SEMCAD. Then it is necessary to use the 'double precision solver' which you set through the preferences in order to allow the solver to determine when the solving has converged. All other solvers DO NOT need double precision

2)What SEMCAD version are you using? This warning should not show up when you actually have 'double precision' solver enabled
3)You do not need to increase the time steps for this.

I think I covered your questions but please do not hesitate to ask in case you need more assistance

Cheers,
Adam