Learning Forum

[s.fazeli]

Hello everyone,

I attached the geometry that I used in Mechanical APDL 21, Once I am using the temperature functions for the BCs, the solver works well but I want to calculate the heat transfer, so I applied the temperature functions (T(r)) along with the heat transfer coefficient functions (htc(r)) based on the radial distributions (using convection surface). Unfortunately, the solver doesn’t work, and I receive the following error message for different elements where are located at the edges:

‘Element 8447 has a convection surface referencing a nonexistent HF material property for material number 136.’

The mesh and the elements mentioned in the error message are shown in the attached picture. Any help or guidance would be really appreciated.

Many thanks,

[mrife]

What element type is element 8447?

[s.fazeli]

Hi,I have been using 2D axisymmetric PLANE55 for the solid part.

[mrife]

Great; what is the command used to define the convection?  Please show actual command with all the field values.

[s.fazeli]

The command : processor>loads>define loads>apply>convection and then I apply two functions for temperature and htc as follows: 

1- For temperature:

*DEL,_FNCNAME   
*DEL,_FNCMTID   
*DEL,_FNCCSYS   
*SET,_FNCNAME,'SHFT'
*SET,_FNCCSYS,0 
! /INPUT,SHFT.func,,,1  
*DIM,%_FNCNAME%,TABLE,6,30,1,,,,%_FNCCSYS%  
!   
! Begin of equation: -1.2012e-09*{Y}^6+2.3877e-06*{Y}^5-0.001975*{Y}^4+0.87027* 
! {Y}^3-215.4642*{Y}^2+28421.3003*{Y}-1560535.1345  
*SET,%_FNCNAME%(0,0,1), 0.0, -999   
*SET,%_FNCNAME%(2,0,1), 0.0 
*SET,%_FNCNAME%(3,0,1), 0.0 
*SET,%_FNCNAME%(4,0,1), 0.0 
*SET,%_FNCNAME%(5,0,1), 0.0 
*SET,%_FNCNAME%(6,0,1), 0.0 
*SET,%_FNCNAME%(0,1,1), 1.0, -1, 0, 6, 0, 0, 3  
*SET,%_FNCNAME%(0,2,1), 0.0, -2, 0, 1, 3, 17, -1
*SET,%_FNCNAME%(0,3,1),   0, -1, 0, -1.2012E-09, 0, 0, -2   
*SET,%_FNCNAME%(0,4,1), 0.0, -3, 0, 1, -1, 3, -2
*SET,%_FNCNAME%(0,5,1), 0.0, -1, 0, 5, 0, 0, 3  
*SET,%_FNCNAME%(0,6,1), 0.0, -2, 0, 1, 3, 17, -1
*SET,%_FNCNAME%(0,7,1), 0.0, -1, 0, 2.3877e-06, 0, 0, -2
*SET,%_FNCNAME%(0,8,1), 0.0, -4, 0, 1, -1, 3, -2
*SET,%_FNCNAME%(0,9,1), 0.0, -1, 0, 1, -3, 1, -4
*SET,%_FNCNAME%(0,10,1), 0.0, -2, 0, 4, 0, 0, 3 
*SET,%_FNCNAME%(0,11,1), 0.0, -3, 0, 1, 3, 17, -2   
*SET,%_FNCNAME%(0,12,1), 0.0, -2, 0, 0.001975, 0, 0, -3 
*SET,%_FNCNAME%(0,13,1), 0.0, -4, 0, 1, -2, 3, -3   
*SET,%_FNCNAME%(0,14,1), 0.0, -2, 0, 1, -1, 2, -4   
*SET,%_FNCNAME%(0,15,1), 0.0, -1, 0, 3, 0, 0, 3 
*SET,%_FNCNAME%(0,16,1), 0.0, -3, 0, 1, 3, 17, -1   
*SET,%_FNCNAME%(0,17,1), 0.0, -1, 0, 0.87027, 0, 0, -3  
*SET,%_FNCNAME%(0,18,1), 0.0, -4, 0, 1, -1, 3, -3   
*SET,%_FNCNAME%(0,19,1), 0.0, -1, 0, 1, -2, 1, -4   
*SET,%_FNCNAME%(0,20,1), 0.0, -2, 0, 2, 0, 0, 3 
*SET,%_FNCNAME%(0,21,1), 0.0, -3, 0, 1, 3, 17, -2   
*SET,%_FNCNAME%(0,22,1), 0.0, -2, 0, 215.4642, 0, 0, -3 
*SET,%_FNCNAME%(0,23,1), 0.0, -4, 0, 1, -2, 3, -3   
*SET,%_FNCNAME%(0,24,1), 0.0, -2, 0, 1, -1, 2, -4   
*SET,%_FNCNAME%(0,25,1), 0.0, -1, 0, 28421.3003, 0, 0, 3
*SET,%_FNCNAME%(0,26,1), 0.0, -3, 0, 1, -1, 3, 3
*SET,%_FNCNAME%(0,27,1), 0.0, -1, 0, 1, -2, 1, -3   
*SET,%_FNCNAME%(0,28,1), 0.0, -2, 0, 1560535.1345, 0, 0, -1 
*SET,%_FNCNAME%(0,29,1), 0.0, -3, 0, 1, -1, 2, -2   
*SET,%_FNCNAME%(0,30,1), 0.0, 99, 0, 1, -3, 0, 0
! End of equation: -1.2012e-09*{Y}^6+2.3877e-06*{Y}^5-0.001975*{Y}^4+0.87027*   
! {Y}^3-215.4642*{Y}^2+28421.3003*{Y}-1560535.1345  
!-->

2- For cht: 

*DEL,_FNCNAME   
*DEL,_FNCMTID   
*DEL,_FNCCSYS   
*SET,_FNCNAME,'SHFH'
*SET,_FNCCSYS,0 
! /INPUT,SHFH.func,,,1  
*DIM,%_FNCNAME%,TABLE,6,30,1,,,,%_FNCCSYS%  
!   
! Begin of equation: -1548885136.978*{Y}^6+2052733225.527*{Y}^5-1116073381.1612 
! *{Y}^4+317882043.211*{Y}^3-49859487.5658*{Y}^2+4063912.5891*{Y}-133440.6545   
*SET,%_FNCNAME%(0,0,1), 0.0, -999   
*SET,%_FNCNAME%(2,0,1), 0.0 
*SET,%_FNCNAME%(3,0,1), 0.0 
*SET,%_FNCNAME%(4,0,1), 0.0 
*SET,%_FNCNAME%(5,0,1), 0.0 
*SET,%_FNCNAME%(6,0,1), 0.0 
*SET,%_FNCNAME%(0,1,1), 1.0, -1, 0, 6, 0, 0, 3  
*SET,%_FNCNAME%(0,2,1), 0.0, -2, 0, 1, 3, 17, -1
*SET,%_FNCNAME%(0,3,1),   0, -1, 0, -1548885136.978, 0, 0, -2   
*SET,%_FNCNAME%(0,4,1), 0.0, -3, 0, 1, -1, 3, -2
*SET,%_FNCNAME%(0,5,1), 0.0, -1, 0, 5, 0, 0, 3  
*SET,%_FNCNAME%(0,6,1), 0.0, -2, 0, 1, 3, 17, -1
*SET,%_FNCNAME%(0,7,1), 0.0, -1, 0, 2052733225.527, 0, 0, -2
*SET,%_FNCNAME%(0,8,1), 0.0, -4, 0, 1, -1, 3, -2
*SET,%_FNCNAME%(0,9,1), 0.0, -1, 0, 1, -3, 1, -4
*SET,%_FNCNAME%(0,10,1), 0.0, -2, 0, 4, 0, 0, 3 
*SET,%_FNCNAME%(0,11,1), 0.0, -3, 0, 1, 3, 17, -2   
*SET,%_FNCNAME%(0,12,1), 0.0, -2, 0, 1116073381.1612, 0, 0, -3  
*SET,%_FNCNAME%(0,13,1), 0.0, -4, 0, 1, -2, 3, -3   
*SET,%_FNCNAME%(0,14,1), 0.0, -2, 0, 1, -1, 2, -4   
*SET,%_FNCNAME%(0,15,1), 0.0, -1, 0, 3, 0, 0, 3 
*SET,%_FNCNAME%(0,16,1), 0.0, -3, 0, 1, 3, 17, -1   
*SET,%_FNCNAME%(0,17,1), 0.0, -1, 0, 317882043.211, 0, 0, -3
*SET,%_FNCNAME%(0,18,1), 0.0, -4, 0, 1, -1, 3, -3   
*SET,%_FNCNAME%(0,19,1), 0.0, -1, 0, 1, -2, 1, -4   
*SET,%_FNCNAME%(0,20,1), 0.0, -2, 0, 2, 0, 0, 3 
*SET,%_FNCNAME%(0,21,1), 0.0, -3, 0, 1, 3, 17, -2   
*SET,%_FNCNAME%(0,22,1), 0.0, -2, 0, 49859487.5658, 0, 0, -3
*SET,%_FNCNAME%(0,23,1), 0.0, -4, 0, 1, -2, 3, -3   
*SET,%_FNCNAME%(0,24,1), 0.0, -2, 0, 1, -1, 2, -4   
*SET,%_FNCNAME%(0,25,1), 0.0, -1, 0, 4063912.5891, 0, 0, 3  
*SET,%_FNCNAME%(0,26,1), 0.0, -3, 0, 1, -1, 3, 3
*SET,%_FNCNAME%(0,27,1), 0.0, -1, 0, 1, -2, 1, -3   
*SET,%_FNCNAME%(0,28,1), 0.0, -2, 0, 133440.6545, 0, 0, -1  
*SET,%_FNCNAME%(0,29,1), 0.0, -3, 0, 1, -1, 2, -2   
*SET,%_FNCNAME%(0,30,1), 0.0, 99, 0, 1, -3, 0, 0
! End of equation: -1548885136.978*{Y}^6+2052733225.527*{Y}^5-1116073381.1612*  
! {Y}^4+317882043.211*{Y}^3-49859487.5658*{Y}^2+4063912.5891*{Y}-133440.6545
!-->

I apply the same procedure for other edges as well. 

Thanks

[mrife]

MAPDL takes a negative value of convection coefficient (HF) to be HF is a function of temperature based on the MP command defining HF.  In this case it is possible for the HF expression to return negative values; not sure if you meant that or not.  In any case that element has a negative HF applied so it is looking for a temperature dependent HF defined via MP.  To change the behavior use SCOPT which has a option to force the use of a negative HF.  See the public help on the command for its options: https://ansyshelp.ansys.com/public/account/secured?returnurl=/Views/Secured/corp/v242/en/ans_cmd/Hlp_C_SCOPT.html

[s.fazeli]

Thank you very much Mrife. I'll read through the document sent by you. Hope it works out. Can I contact you again if there was any issue to apply for the new command?