Electric-thermal案例

alex_shoal

本人在试着粗算一下AWG12的裸铜线的温升。
但是感觉结果会和实际差很多。
excel算是17度温升，
ANSYS算是3度温升。
不知道那个会更接近实际。
望高手指点。谢谢。
现附APDL，供大家提意见。


!CABLE TEMPERATURE RISE ANALYSIS
!ELECTRICAL-THERMAL CASE
!2010-3-18 BY ALEX SHOAL
!EMAIL:ALEX.SHOAL@GMAIL.COM
!------FILE ENVIRONMENT
FINISH
/CLEAR,
/COM,  Thermal
/FILNAME,Cable_thermal,0
/SHOW,WIN32c         ! Use /SHOW,X11C for UNIX
/CONT,1,255           !set up the number of contours
!LOCA=1 means at home,else means in office.
LOCA=2
*IF,LOCA,EQ,1,THEN
/CWD,'E:\'
*ELSE
/CWD,'D:\'
*ENDIF


!**********PARAMETER SETUP
! *** Set convection coefficients of surrounding
h1 = 4e-6     !W/mm^2*C
! *** Set electrical resistivities
rho1 = 1.68e-5  !ohm*mm - 100%  !resistivity of copper
! *** Set thermal conductivities
kx1 = 0.385     !W/mm C          !conductivity of Copper
! *** set the specific heat capacity
c_cable=0.385
!*** INPUT DATA
!AWG 12
cur_load = 9.3      !Amount of current in model
L=20           !LENGTH OF CABLE
DIA=2.05232    !DIAMETER OF CABLE,UNIT:mm
Ts=25          !TEMPERATURE OF SUROUND
!***
/prep7

CYL4,0,0,DIA
VOFFST,1,L
/prep7
! *** create model of cable ***
ET,1,SOLID69
! *** Material Properties - CABLE ***
mp,kxx,1,kx1
mp,rsvx,1,rho1
!MP,C,1,0.400
VSEL,S,VOLU,,1
VATT,1,,1                  
ESIZE,0.4
VSEL,S,VOLU,,1
VSWEEP,ALL
!------SOLUTION
/solu
! *** Apply current ***
ASEL,S,AREA,,1
NSLA,S,1
cp,next,volt,all
!cp,next,temp,all
*get,cur_1,node,,num,min
f,cur_1,amps,cur_load
! *** Apply 0 Voltage ***
ASEL,S,AREA,,2
NSLA,S,1
cp,next,volt,all
!cp,next,temp,all
*get,volt_0,node,,num,min
d,volt_0,volt,0
! *** Apply Convection ***
ASEL,ALL
ASEL,U,AREA,,1,2
nsla,s,1
SF,ALL,CONV,H1,Ts                      !set up the convection condition with surrounding for all outside surface.
!SF,ALL,RDSF,0.9,1
TOFFST,273                          !set the offset between the absolute zero and zero.
TUNIF,Ts                            !setup the original temperature
/SOLU
allsel
TIME,1
outres,all,all
NSUBST,50,100,5
save
solve

/post1
set,1
!/triad,off
*get,JBNM,active,0,jobnam
!h5a = h1
/title,2010-3-15, %JBNM%, I = %cur_load%, h = %h1%,
! *** Plot Temperature Distribution ***
plnsol,temp

yunyihu

Excel 对流换热系数是4，好像比较小。还有导线与重力的方向，你excel怎么考虑？

alex_shoal

2# yunyihu .excel和ansys中的换热系数都是4，并没有差别。
另外excel中
主要是利用
h*A*T_rise=P=I^2*R
来计算