harmonic solution time steps

[WouterBeerten]

Hi All,

I am currently working on a harmonic solution in ansys.
I am a novice into ansys, actually first time user. I am working on a tube that has a highfrequent ac current running through its outer layer. Induced by a coil. (skineffect)
I am able to plot the current density against the radius (depth) of the pipe. However I want a solution in more time steps throughout the harmonic wave. I am now trying 3 days and can't get ansys to give me different solutions of the induced current evolving in time. The frequency I use is 6 Mhz.

could anyone help me out ?
I would be very thankfull because I need this simulation results to build a measurement cell.

The code I use :


//prep7

/pnum,kp,1
/pnum,line,1
/pnum,area,1
/pnum,mat,1
!!!!!!!!!
! Constants
!!!!!!!!!
*SET,r_i,0.004 !tube inner diameter
*SET,r_o,0.005 !tube outer diameter
*SET,r_sp,0.010 !Coil radius
*SET,h_ox,20E-6 !oxide layer thickness
*SET,h_slg,20E-6 !slagging layer thickness
*SET,h_sp,0.0008 !coil thickness
*SET,w_sp,0.008 !coil width
*SET,d,0.005 !coil displacement from edge
*SET,A,0.05 !environment length
*SET,L,0.06 !tube length
*SET,Ex,0.02 !excentricity from origin
*SET,a_sp,h_sp*w_sp !Coil cross section area
*SET,N,10 !Number of coil turns
*SET,i,1 !Current in z-direction
*SET,F,0,95 !Coil Fill factor

!!!!!!!!!
! Geometry
!!!!!!!!!
rectng,EX,EX+L,0,r_i ! Water region
aatt,1
asel,none

rectng,0,2*EX+L,0,A ! Air region
aatt,4
asel,none

rectng,EX,EX+L,r_i,r_o-h_ox ! Steel
aatt,2
asel,none

rectng,EX,EX+L,r_o-h_ox,r_o ! Oxide film
aatt,3
asel,none

rectng,EX,EX+L,r_o,r_o+h_slg ! Slag film
aatt,3
asel,none

rectng,EX+d,EX+d+w_sp,r_sp,r_sp+h_sp ! Coil1 (links)
rectng,EX+L-d-w_sp,EX+L-d,r_sp,r_sp+h_sp! Coil2 (rechts)
aatt,5
asel, none

allsel ! Subtraction areas
asba,2,ALL,SEPO,,KEEP
asel,s,,,8
aatt,4
asel,none


allsel
asum, default
*get,a,area,,area
asel,none

allsel
nummrg,kp,1.E-6

!!!!!!!!!
! Elements definition, Material properties, Real constants, Meshing
!!!!!!!!!

et,3,53,0,,1 ! Oxide film
type,3
mp,murx,3,1
mp,rsvx,3,1.0E-7
lsel,s,line,,11
lesize,all,,,150
allsel

lsel,s,line,,15
lesize,all,,,150
allsel

lsel,s,line,,14
lesize,all,,,25
allsel

lsel,s,line,,16
lesize,all,,,25
allsel

asel,s,mat,,3
mshape,0,2d
amesh,4
allsel


et,2,53,0,,1 ! Steel
type,2
mp,murx,2,1
mp,rsvx,2,1.0E-7

lsel,s,line,,3
lesize,all,,,200
allsel

lsel,s,line,,11
lesize,all,,,200
allsel

lsel,s,line,,10
lesize,all,,,40,1/20
allsel

lsel,s,line,,12
lesize,all,,,40,20
allsel

asel,s,mat,,2
mshape,0,2d
amesh,3
allsel


et,5,53,2,,1 ! Coil 1 (links)
type,5
mp,murx,5,1
mp,rsvx,5,1.78E-8
R,

lsel,s,line,,22
lesize,all,,,10
allsel

lsel,s,line,,24
lesize,all,,,10
allsel

lsel,s,line,,21
lesize,all,,,30
allsel

lsel,s,line,,23
lesize,all,,,30
allsel

asel,s,mat,,5
amesh,6
r,1,2*a,n,,-1,1
allsel


et,6,53,2,,1 ! Coil 2 (rechts)
type,5
mp,murx,5,1
mp,rsvx,5,1.78E-8

lsel,s,line,,26
lesize,all,,,10
allsel

lsel,s,line,,28
lesize,all,,,10
allsel

lsel,s,line,,25
lesize,all,,,30
allsel

lsel,s,line,,27
lesize,all,,,30
allsel

asel,s,mat,,5
amesh,7
r,1,2*a,n,,-1,1
allsel



et,1,53,0,,1 ! Air(/Water)
type,1
mp,murx,1,1
mp,rsvx,1,3E13

lsel,s,line,,1
lesize,all,,,200
allsel

lsel,s,line,,3
lesize,all,,,200
allsel

lsel,s,line,,2
lesize,all,,,20
allsel

lsel,s,line,,4
lesize,all,,,20
allsel

asel,s,mat,,1
mshape,1,2d
amesh,1
allsel


et,3,53,0,,1 ! Slag layer
type,3
mp,murx,3,1
mp,rsvx,3,1.0E-7

lsel,s,line,,15
lesize,all,,,150
allsel

lsel,s,line,,19
lesize,all,,,150
allsel

lsel,s,line,,18
lesize,all,,,35
allsel

lsel,s,line,,20
lesize,all,,,35
allsel

asel,s,mat,,3
mshape,0,2d
amesh,5
allsel


et,4,53,0,,1 ! Surroundings (Air)
type,4
mp,murx,4,1
mp,rsvx,4,3E13


asel,s,mat,,4
mshape,1,2d
amesh,8
allsel
!!!!!!!!!
! Boundary conditions
!!!!!!!!!

asel,s,mat,,2,3,1,1 ! Coupling VOLT DOFs for conducting
nsla,s,1 ! regions (steel & oxide film)
cp,1,volt,all
allsel

asel,s,area,,6,6,1,1 ! Coupling CURR DOFs for coil 1
nsla,s,1
cp,2,curr,all
allsel

asel,s,area,,7,7,1,1 ! Coupling CURR DOFs for coil 2
nsla,s,1
cp,3,curr,all
allsel

nsel,s,loc,y,0
d,all,az,0 ! flux-parallel condition (axial line)
allsel

csys,0
fini


!!!!!!!!!
! Solution
!!!!!!!!!
/solu

antype,harm

asel,s,area,,6,6,1,1
esla,s,1
bfe,all,vltg,,1 ! voltage load
allsel



outres,all,all
autots,on
deltime, 0.1E-6
harfrq,0,6E6
solve


!!!!!!!!!
/post1 ! Post-processing
!!!!!!!!!
allsel
asel,s,area,,3,5,1,1
PLESOL,JT,SUM,0 ! Total current density in steel
!& oxide film
ETABLE, ,JT,Z
!*
PATH,cutline,2,30,30,
PPATH,1,0,0.2900000E-01,0.502E-02,0,0,
PPATH,2,0,0.2900000E-01,0.472E-02,0,0,
!*
PDEF, ,ETAB,JTZ,AVG
/PBC,PATH, ,0
!*
PLPATH,ETABJTZ
PRPATH,ETABJTZ
/EOF

 

[meshparts]

Hello

I would recommend you to read the Ansys help Chapter 4. Harmonic Response Analysis for the basics.

Then you will know how to define the solution options for a harmonic analysis. For example you don't use the command DELTIM. Use instead NSUBST.

Anyway I don't understand why you have set deltim,0.1E-6 where the frequency range is harfrq,0,6E6. Even if deltim would work, you would get a total of 60e12 time steps!

Regards
Alex

 

[WouterBeerten]

Hi Alex,

Thx I found it out

Another problem does anyone now how to pick up the induction in the receiver coil, one I use to induce the current in the bar, the other one is to pick it up.

grtz Wouter