Does someone here konw about thermoelectric analysis with ANSYS, I've got some question to ask.
I am quite intrested in thermoelectric cooler and want to simulate it with ANSYS. But I got a problem.
I read the ANSYS 9.0 documentation and found an example of thermoelectric cooler. I modified it in the foolowing step.
- In the original model, the temperature of the two junctions are fixed. In order to simulate some 'real' conditions, I applied convection loads on the junctions. On the cold junction, the film coeffiency is normal and on the other one, the film coefficency is quite large.
- The original example applied a static analysis. But in some conditions, transient analysis is requied. So I applied a new transient analysis.
After the simulation, I got a curve of temperature of the cold junction according to time. But the problem came out.
First I set the analyse time to 20 and the final cold junction temperature is about 24 deg.C. The second time, I set the time to 50, the temperature is the same! In my opinion, the first curve should be part of the second one. But now, the second one seemes to be the first curve, stretched 2.5 times according time.
It' quite werid. I look up the ANSYS 9.0 documentation and found that the thermoelectric analyse was a new function of that version of the software. I searched the library, but coludn't get any help.
Hope someone could answer me this question.
Post my batch code in the following: !================================================================== FILNAME, THERMOELECTRIC COOLER /TITLE, THERMOELECTRIC COOLER /VUP,1,Z ! specifies the global cartesian coordinate system reference orientation. /VIEW,1,1,1,1 ! view point /TRIAD,OFF ! /NUMBER,0 ! show colors and numbers /UNITS,SI ! standard international units !/NOPR
/PREP7 L=1E-2 ! element height W=1E-2 ! element width and length HS=2E-3 ! strap height
TOFFST,273 ! temperature offset, deg.C
! N-type material MP,RSVX,1,1E-5 ! electrical resistivity, ohm*m MP,KXX,1,1.8 ! thermal conductivity, watt/(m*k) MP,SBKX,1,-170E-6 ! seebeck coefficient, volt/k MP,DENS,1,3E3 ! density, kg/(m^3) MP,C,1, 0.8e3 ! specific heat, Joule/(kg*deg.C)
! P-type material MP,RSVX,2,0.769E-5 ! electrical resistivity, ohm*m MP,KXX,2,1.4 ! thermal conductivity, watt/(m*k) MP,SBKX,2,180E-6 ! seebeck coefficient,volt/k MP,DENS,2,3e3 ! density, kg/(m^3) MP,C,2, 0.8e3 ! specific heat, Joule/(kg*deg.C)
! connecting straps (copper) MP,RSVX,3,1.7E-8 ! resistivity, ohm*m MP,KXX,3,400 ! thermal conductivity, watt/(m*k) MP,DENS,3,8.9e3 ! density, kg/(m^3) MP,C,3,0.39E3 ! specific heat, Joule/(kg*deg.C)
! FE model ET,1,226,110 ! 20-NODE THERMO-ELECTRIC BRICK ET,2,227,110 ! 10-NODE THERMO-ELECTRIC TET
! modeling BLOCK,W/2,3*W/2,,W,,L BLOCK,-3*W/2,-W/2,,W,,L BLOCK,-3*W/2,3*W/2,,W,L,L+HS BLOCK,-1.7*W,-W/2,,W,-HS,0 BLOCK,W/2,1.7*W,,W,-HS,0 VGLUE,ALL
ESIZE,W/5 ! element size TYPE,1 ! element type 1 MAT,1 ! material type 1 VMESH,1 ! mesh volume 1 MAT,2 ! material type 2 VMESH,2 ! mesh volume 2 TYPE,2 ! element type 2 MAT,3 ! material type 3 LESIZE,61,HS/3 LESIZE,69,HS/3 LESIZE,30,W/8 LESIZE,51,W/8 LESIZE,29,W/8 LESIZE,50,W/8 VMESH,6,8 ! mesh connecting straps EPLOT
! boundary conditions and loads NSEL,S,LOC,Z,L+HS ! select cold junction CP,1,TEMP,ALL ! couple temp dofs NC=NDNEXT(0) ! get master node number
NSEL,S,LOC,X,-1.7*W ! first electric terminal D,ALL,VOLT,0 ! ground
NSEL,S,LOC,X,1.7*W ! second electric terminal CP,2,VOLT,ALL ! couple volt dofs NI=NDNEXT(0) ! get master node NSEL,ALL
FINI
/SOLU ! solve begin ANTYPE,4 ! transient solve
TIME,50 ! total solve time DELTIM,5,2,10 ! specify step OUTRES,ALL,1 ! wirte every step to file
TUNIF,27 ! initial temperature distribution
NSEL,S,LOC,Z,L+HS ! convection on all nodes on the cold junction SF,ALL,CONV,0.014,27 NSEL,S,LOC,Z,-HS ! convection on all nodes on the hot junction SF,ALL,CONV,500,27
I=28.7 ! input current F,NI,AMPS,I ! apply current i, amps to the master node
ALLSEL SOLVE
/POST26 NSOL,4,NODE(0,W/2,-HS),TEMP,,T_H NSOL,3,NODE(0,W/2,L+HS),TEMP,,T_C PLVAR,3,4 FINISH !=================================================================