对Hyperworks版老向发的两块板的热分析的求解遇到的问题

epingaixiao

前处理是在hypermesh做的,只是最后加载方式是在ANSYS中,因为在Hypermesh中不知道怎么加载沿着径向的heat flux.图1是我加载heat flow的警告信息,查了下帮助文件,heat flow在加载线单元时用到,而对于实体单元最好转化成热流密度加载,但原问题只提供了heat flow,
       图2与图3是我采用原问题的结果,在内圈加载恒温48.358。
       图4与图5是我把边界条件改成热流密度是100瓦/平方米,加载方式是选ON Nodes,算出的最高温度是36.524,图6的加载方式选ON Elements,算出的最高温度是30.762,不知道为什么这两种加载方式会引起不同的结果。
      图7与图8是问题描述。
       很少接触热方面的,望高手指点迷津。

iomega

are you sure you had applied 100W/m^2 heat flux in your cases?    The inner cylinder area is Pi*20mm*4mm = 0.00025 m^2  so the total power input will be only 0.025W, instead of 100W. Thus there should be almost no temperature rise in the plates, neither 30.762 C  or 36.524C.

epingaixiao

Well, I have no idea how to calculated the heat flux, I know the inner cylinder area is 0.000251 m^2,but whether the heat flux equals to the heat flow divided by the surface area, or What was the heat flux I should apply in the case,please give me more advice!

iomega

heat flux is power/area with unit of W/m^2.
Can you upload the code that applies that uploads the heat flux so I can tell what's going on...

epingaixiao

In this case, if I applied 398089.2 heat flux which is just the power/area, but the max temperture is 45901 as the figure shows, the reference result is 48.358.

iomega

I suspect the boundary condition is wrong.Upload your APDL code then we can take a look on the problem.BTW, I tried this model in IcePak using the heat flux of 398089.2 W/m^2-K and it shows max temperature around 48.8C

epingaixiao

BATCH  
/COM,ANSYS RELEASE 10.0    UP20050718       15:29:51    01/13/2010
/input,menust,tmp,'',,,,,,,,,,,,,,,,1   
/GRA,POWER
/GST,ON
/PLO,INFO,3
/GRO,CURL,ON
/CPLANE,1   
/REPLOT,RESIZE  
WPSTYLE,,,,,,,,0
/INPUT,'plate_thermal','inp','D:\Simwe_Interview_Problem_plate\Ansys_slover\thermal\',, 0   
/VIEW,1,1,1,1   
/ANG,1  
/REP,FAST   
/VIEW,1,,,1
/ANG,1  
/REP,FAST   
/VIEW,1,1   
/ANG,1  
/REP,FAST   
EPLOT   
/SOLU   
FLST,2,168,1,ORDE,119   
FITEM,2,394
FITEM,2,-400
FITEM,2,549
FITEM,2,-554
FITEM,2,717
FITEM,2,-722
FITEM,2,874
FITEM,2,-878
FITEM,2,4626
FITEM,2,-4630   
FITEM,2,4632
FITEM,2,4634
FITEM,2,4873
FITEM,2,-4876   
FITEM,2,4878
FITEM,2,4880
FITEM,2,4939
FITEM,2,-4942   
FITEM,2,4944
FITEM,2,4946
FITEM,2,5067
FITEM,2,-5068   
FITEM,2,5070
FITEM,2,-5071   
FITEM,2,5073
FITEM,2,5250
FITEM,2,-5254   
FITEM,2,5256
FITEM,2,5258
FITEM,2,5497
FITEM,2,-5500   
FITEM,2,5502
FITEM,2,5504
FITEM,2,5563
FITEM,2,-5566   
FITEM,2,5568
FITEM,2,5570
FITEM,2,5691
FITEM,2,-5692   
FITEM,2,5694
FITEM,2,-5695   
FITEM,2,5697
FITEM,2,5874
FITEM,2,-5878   
FITEM,2,5880
FITEM,2,5882
FITEM,2,6121
FITEM,2,-6124   
FITEM,2,6126
FITEM,2,6128
FITEM,2,6187
FITEM,2,-6190   
FITEM,2,6192
FITEM,2,6194
FITEM,2,6315
FITEM,2,-6316   
FITEM,2,6318
FITEM,2,-6319   
FITEM,2,6321
FITEM,2,6498
FITEM,2,-6501   
FITEM,2,6503
FITEM,2,6505
FITEM,2,6507
FITEM,2,6745
FITEM,2,-6747   
FITEM,2,6749
FITEM,2,6752
FITEM,2,6754
FITEM,2,6811
FITEM,2,-6813   
FITEM,2,6815
FITEM,2,6817
FITEM,2,6819
FITEM,2,6937
FITEM,2,-6938   
FITEM,2,6941
FITEM,2,6945
FITEM,2,6947
FITEM,2,7122
FITEM,2,-7125   
FITEM,2,7127
FITEM,2,7129
FITEM,2,7131
FITEM,2,7369
FITEM,2,-7371   
FITEM,2,7373
FITEM,2,7376
FITEM,2,7378
FITEM,2,7435
FITEM,2,-7437   
FITEM,2,7439
FITEM,2,7441
FITEM,2,7443
FITEM,2,7561
FITEM,2,-7562   
FITEM,2,7565
FITEM,2,7569
FITEM,2,7571
FITEM,2,7746
FITEM,2,-7749   
FITEM,2,7751
FITEM,2,7753
FITEM,2,7755
FITEM,2,7993
FITEM,2,-7995   
FITEM,2,7997
FITEM,2,8000
FITEM,2,8002
FITEM,2,8059
FITEM,2,-8061   
FITEM,2,8063
FITEM,2,8065
FITEM,2,8067
FITEM,2,8185
FITEM,2,-8186   
FITEM,2,8189
FITEM,2,8193
FITEM,2,8195
/GO
!*  
SF,P51X,HFLUX,398089.2  
/USER,  1   
/VIEW,  1,  0.888617232655    , -0.458649554484    ,   0.00000000000
/REPLO  
/STATUS,SOLU
SOLVE   
FINISH  
/POST1  
!*  
/EFACET,1   
PLNSOL, TEMP,, 0

epingaixiao

And this is .inp file.
!! ANSYS Input Deck Generated by HyperMesh Version  : 8.0
!! Generated using HyperMesh-Ansys Template Version : 8.0
/TITLE,A simple thermal analysis                                               
/PREP7
ANTYPE,  static,     new
!!  NODE Data
CSYS,0
N,372,             0.0,           -50.0,            50.0
......
!!HMNAME MAT
!!         1 "bottom_mat"
MPTEMP,1,             0.0
MP,KXX ,1,           400.0
!!HMNAME MAT
!!         2 "top_mat"
MPTEMP,1,             0.0
MP,KXX ,2,           200.0
!!HMNAME ET
!!         1 "ET_1"
ET,1,70
!!HMNAME COMP
!!   1-1-1 "bottom"
!!HWCOLOR COMP
!!   1-1-1 39
TYPE, 1  $ MAT, 1  $ REAL, 1
ESYS, 0
EN,    1693,    5837,    5834,    5835,    5836,    6458,    6461,    6460,    6459
.....
CM, top, ELEM
ESEL, NONE
ESEL, ALL

!! Loadstep Data

!! Loadstep Data (all loads and boundary conditions).
LSCLEAR, ALL
!!HMNAME LOADCOL
!!        13 "N_temperture"
!!HWCOLOR LOADCOL
!!        13       31
D,372,TEMP,25.0
.......
LSWRITE,1

! Exit PREP7 processor
FINISH
! Enter SOLU processor
/SOLU
FINISH

epingaixiao

Please check, thank you.

iomega

can you attach the inp file itself?

epingaixiao

This is the inp file.

epingaixiao

如果我在设置热传导系数时输入400000与200000，则温度分布接近参考结果。

iomega

N,372,             0.0,           -50.0,            50.0

it looks like that the dimensions of the structure is 100m, not 100mm.

So you have to change all the node definitions to the mm size.

epingaixiao

I got it, thank you. As the default unit of length in hypermesh is mm, So I should convert the heat flux and KXX units, then the result is right.

iomega

BTW, what load applying approach did you use to get the correct results with 200000/400000 W/m-K thermal conductivity values? node loads or element load?

Thanks!

epingaixiao

node loads