高手看看，这个问题应该如何分析，谢谢。

freemoon

这是模型的截面图，120度方向均布3根导线，通电流为I，电流方向垂直于图面向外，周围是空气，然后是硅胶层，硅胶层外面是流体，方向垂直于图面向内。
想作瞬态分析，得到随时间变化，模型温度场的变化
这个模型中分析 应当考虑那些 东西？
硅胶层内部是不是应当：辐射，自然对流，导热都得考虑？
硅胶层内是导热
硅胶层外部是强制对流？

iomega

这个模型中分析 应当考虑那些 东西？
For this model you can only consider the 1/3 of the whole circle.

硅胶层内部是不是应当：辐射，自然对流，导热都得考虑？
no nature convection since there is no gravity difference in the paper plane ...
consider air conduction, if the temprature rise of the wire is too high, say >200C, consider the radiation.

硅胶层内是导热
yes,

硅胶层外部是强制对流？
yes

freemoon

Thanks very much!
BTW,
1.the outer diameter is very small,about 1.2mm--5mm
Is there any difference to the big size of this model?
or what's more need to be considerd?
2.no nature convection ?
It's the section of a 3Dmodel,
For the 3Dmodel, no nature convection ?
3.temp of the wire<100C
So the radiation can be negelected, what's your basis?
Compare to  'thermal conduction' , since the thermal conductivity of the air is very small, can the radiation be negelected?

thanks very much!

iomega

BTW,
1.the outer diameter is very small,about 1.2mm--5mm
Is there any difference to the big size of this model?
not clear what you are saying...

or what's more need to be considerd?

2.no nature convection ?
It's the section of a 3Dmodel,
For the 3Dmodel, no nature convection ?
I had thought you want a 2D problem.
What are the boundary conditions at top and bottom sides? The conditions will determine wether you need nature convction.

3.temp of the wire<100C
So the radiation can be negelected, what's your basis?
Should be ignored. you can judge it by calculate the thermal resistance for both air conduction and radiation, even assuming e=1.

Compare to 'thermal conduction' , since the thermal conductivity of the air is very small, can the radiation be negelected?

freemoon

in chinese:
这个是整体的一节，上/下面都和结构相同的另一节相连，
由于长度方向尺寸比截面尺寸大好多倍，我是想简化模型，只分析截面，也就是最初的那个平面图。

空间非常狭小，整体尺寸为1.2mm--5mm，其中空气是被密封起来的，要考虑自然对流么？如果考虑，对流换热系数会很复杂把，和内部空气温度升高还有关系？

另外，这种模型的辐射热阻不好计算吧