1. Heat sink analysis: analytically and via ANSYS ME 340 Final Project - Dr. Soloviev - Fall 2010 by Mathew Marshal & Kevin Hoopes

2. Problem definition Intel core i7 processors can dissipate up to 130W under full load They must be kept below 373 K to prevent hardware damage We are given a certain rectangular fin, integral heat sink Find the required convection coefficient to keep the base below 373 K.

3. Boundary Conditions Base exposed to constant heat input of 130W Sides of base are adiabatic Sides and tops of fins are exposed to convective heat transfer to surrounding atmosphere at 298 K Heat sink is solid Aluminum

4. ANSYS Solution Define Geometry Apply boundary conditions Mesh Solve

5. ANSYS Solution Results obtained for initial guess for h Iterated until base temperature reached approximately 373 K h value found to be 37.6 W*K/m^2

6. Analytical Solution h = 39.8 W*K/m^2

7. Summary ANSYS Solution – 37.5 Analytical Solution – 39.8

8. Appendix Analytical Solution ANSYS Log file

10. *SET,_REMOTE_VIS_ID,'39' WPSTYLE,,,,,,,,0 /PREP7 !DEFINE THE BLOCK BLC4,0,0,0.042,0.001,0.045 !MAKE A FIN BLC4,0,0.001,0.0021,0.055,0.045 !COPY THE FINS FLST,3,1,6,ORDE,1 FITEM,3,2 VGEN,2,P51X,,,0.004433333,,,,0 FLST,3,1,6,ORDE,1 FITEM,3,3 VGEN,2,P51X,,,0.004433333,,,,0 FLST,3,1,6,ORDE,1 FITEM,3,4 VGEN,2,P51X,,,0.004433333,,,,0 FLST,3,1,6,ORDE,1 FITEM,3,5 VGEN,2,P51X,,,0.004433333,,,,0 FLST,3,1,6,ORDE,1 FITEM,3,6 VGEN,2,P51X,,,0.004433333,,,,0 FLST,3,1,6,ORDE,1 FITEM,3,7 VGEN,2,P51X,,,0.004433333,,,,0 FLST,3,1,6,ORDE,1 FITEM,3,8 VGEN,2,P51X,,,0.004433333,,,,0 FLST,3,1,6,ORDE,1 FITEM,3,9 VGEN,2,P51X,,,0.004433333,,,,0 FLST,3,1,6,ORDE,1 FITEM,3,10 VGEN,2,P51X,,,0.004433333,,,,0 FLST,2,11,6,ORDE,2 FITEM,2,1 FITEM,2,-11 VADD,P51X FINISH /SOL FINISH /PREP7 !DEFINE ELEMENT TYPE ET,1,SOLID70 ET,2,SOLID70 MPTEMP,,,,,,,, MPTEMP,1,0 !DEFINE CONDUCTION COEFICIENT MPDATA,KXX,1,,250 FLST,2,59,5,ORDE,23 FITEM,2,10 FITEM,2,12 FITEM,2,-14 FITEM,2,16 FITEM,2,-20 FITEM,2,22 FITEM,2,-26 FITEM,2,28 FITEM,2,-32 FITEM,2,34 FITEM,2,-38 FITEM,2,40 FITEM,2,-44 FITEM,2,46 FITEM,2,-50 FITEM,2,52 FITEM,2,-56 FITEM,2,58 FITEM,2,-60 FITEM,2,64 FITEM,2,-65 FITEM,2,67 FITEM,2,-81 /GO !DEFINE CONVECTION COEFICIENT, THIS IS ITERATED TO OBTAIN THIS SOLUTION SFA,P51X,1,CONV,37.60,298 FLST,2,4,5,ORDE,4 FITEM,2,5 FITEM,2,-6 FITEM,2,82 FITEM,2,-83 /GO FLST,2,1,5,ORDE,1 FITEM,2,3 /GO !DEFINE HEAT FLUX ON BOTTOM OF HEAT SINK SFA,P51X,1,HFLUX,68783 FINISH /SOL FINISH /POST1 FINISH /PREP7 SMRT,6 SMRT,2 SMRT,1 MSHAPE,1,3D MSHKEY,0 CM,_Y,VOLU VSEL,,,, 12 CM,_Y1,VOLU CHKMSH,'VOLU' CMSEL,S,_Y VMESH,_Y1 CMDELE,_Y CMDELE,_Y1 CMDELE,_Y2 FINISH /SOL SOLVE FINISH