QUESTION:
What is the procedure for using SURF152 to define both convection and radiation acting on one side of a mesh of SHELL131 layered shell elements having throug thickness conduction capability.
ANSWER:
An example input file is listed below. Procedure can be inferred from comments and commands appearing in the listing.
fini
/cle
C*********************************************************
C*** MODEL DEMONSTRATES PROCEDURE TO USE SURF152 TO
C*** CONVECT AND RADIATE HEAT AWAY FROM THE TOP
C*** SURFACE OF SHELL131 LAYERED THERMAL SHELL
C*** HAVING THRU THICKNESS CONDUCTION. A TRANSIENT IS
C*** PERFORMED.
C*********************************************************
/sys,del *.png
/vie,1,3,2,1
/vup,1,z
/esha,1
/pnu,mat,1
/num,1
C*********************************************************
C*** PARAMETERS
C*********************************************************
a=0.100 ! PLATE EDGE LENGTH (m)
t=0.010 ! PLATE THICKNESS (m)
k=1 ! PLATE THERMAL CONDUCTIVITY (W/m-C)
emsvty=1.0 ! EMMISSIVITY
formf=1 ! FORM FACTOR
Hc=5 ! CONVECTION COEFFICIENT (W/m^2-C)
Ht_area=500 ! HEAT FLUX APPLIED TO UNCOOLED SIDE OF PLATE (W/m^2)
T_env=21 ! ENVIRONMENT TEMPERATURE (C)
t_final=500 ! END OF THERMAL XSIENT
z_xtra=-1*t ! Z COORDINATE OF RADIATION XTRA NODE
C*********************************************************
C*** GEOMETRY
C*********************************************************
/prep7
rect,-a/2,a/2,-a/2,a/2
C*********************************************************
C*** ATTRIBUTES
C*********************************************************
et,1,131 ! PLATE (LAYERED THERMAL SHELL)
keyopt,1,3,0 ! UP TO 15 LAYERS, QUADRATIC TEMP THRU t
keyopt,1,4,1 ! ONE LAYER THRU t
sectype,1,shell ! SECTION PROPERTIES
secdata,t,1
mp,kxx,1,k
mp,dens,1,7800
mp,c,1,5
et,2,152 ! CONVECTION SURFACE EFFECT ELEMENTS
keyopt,2,4,1 ! NO MIDSIDE NODES
keyopt,2,8,2 ! EVALUATE Hc @ AVERAGE TEMP
r,2
|
QUESTION: What is the procedure for using SURF152 to define both convection and radiation acting on one side of a mesh of SHELL131 layered shell elements having throug thickness conduction capability. ANSWER: An example input file is listed below. Procedure can be inferred from comments and commands appearing in the listing. fini /cle C********************************************************* C*** MODEL DEMONSTRATES PROCEDURE TO USE SURF152 TO C*** CONVECT AND RADIATE HEAT AWAY FROM THE TOP C*** SURFACE OF SHELL131 LAYERED THERMAL SHELL C*** HAVING THRU THICKNESS CONDUCTION. A TRANSIENT IS C*** PERFORMED. C********************************************************* /sys,del *.png /vie,1,3,2,1 /vup,1,z /esha,1 /pnu,mat,1 /num,1 C********************************************************* C*** PARAMETERS C********************************************************* a=0.100 ! PLATE EDGE LENGTH (m) t=0.010 ! PLATE THICKNESS (m) k=1 ! PLATE THERMAL CONDUCTIVITY (W/m-C) emsvty=1.0 ! EMMISSIVITY formf=1 ! FORM FACTOR Hc=5 ! CONVECTION COEFFICIENT (W/m^2-C) Ht_area=500 ! HEAT FLUX APPLIED TO UNCOOLED SIDE OF PLATE (W/m^2) T_env=21 ! ENVIRONMENT TEMPERATURE (C) t_final=500 ! END OF THERMAL XSIENT z_xtra=-1*t ! Z COORDINATE OF RADIATION XTRA NODE C********************************************************* C*** GEOMETRY C********************************************************* /prep7 rect,-a/2,a/2,-a/2,a/2 C********************************************************* C*** ATTRIBUTES C********************************************************* et,1,131 ! PLATE (LAYERED THERMAL SHELL) keyopt,1,3,0 ! UP TO 15 LAYERS, QUADRATIC TEMP THRU t keyopt,1,4,1 ! ONE LAYER THRU t sectype,1,shell ! SECTION PROPERTIES secdata,t,1 mp,kxx,1,k mp,dens,1,7800 mp,c,1,5 et,2,152 ! CONVECTION SURFACE EFFECT ELEMENTS keyopt,2,4,1 ! NO MIDSIDE NODES keyopt,2,8,2 ! EVALUATE Hc @ AVERAGE TEMP r,2 rmore,1e-10 et,3,152 ! RADIATION SURFACE EFFECT ELEMENTS keyopt,3,4,1 ! NO MIDSIDE NODES keyopt,3,5,1 ! RADIATION REQUIRES XTRA NODE keyopt,3,9,1 ! RADIATION WITH FORM FACTOR REAL CONST r,3,formf,5.67e-8 ! FORM FACTOR, SB CONST rmore,1e-10 mp,emis,3,emsvty C********************************************************* C*** FINITE ELEMENT MODEL C********************************************************* n,1,,,z_xtra ! DEFINE XTRA NODE mat,1 $type,1 $real,1 $secnum,1 ! MESH PLATE ames,all mat,2 $type,2 $real,2 ! CONVECTION SURFACE EFFECT ELEMS esurf mat,3 $type,3 $real,3 ! RADIATION SURFACE EFFECT ELEMS esurf,1 C********************************************************* C*** BOUNDARY CONDITIONS C********************************************************* toffs,273 d,1,temp,T_env ! XTRA NODE TEMP esel,s,type,,2 ! CONVECTION BC's ON CONVECTION SURF EFCT ELEMS sfe,all,,conv,1,Hc sfe,all,,conv,2,T_env esel,s,type,,1 ! HEAT FLUX ON PLATE (SIDE OPPOSITE CONV & RAD SURFACE) sfe,all,1,hflux,,Ht_area alls ! SET TTOP=TEMP TO COUPLE SHELL131 TO SURF152 nsel,u,node,,1 *get,nnds,node,,count nd=0 *do,i,1,nnds nd=ndnext(nd) ce,next,0,nd,temp,1,nd,ttop,-1 *enddo fini C********************************************************* C*** SOLVE C********************************************************* /solu anty,trans time,t_final autots,on nsub,100,100,2 outres,all,all kbc,1 tuni,t_env alls eplo save solv fini C********************************************************* C*** POSTPROCESSING C********************************************************* /post1 esel,s,type,,1 nsle layer,1 plns,temp ! PLATE TEMPERATURE CONTOUR /sho,png $/rep $/sho,close $/wait,2 fini /post26 ! TOP AND BOTTOM SURFACE TEMPS vs time nsol,2,2,tbot,,T_hotside nsol,3,2,ttop,,T_coolside axl,y,Temperature (C) plva,2,3 /sho,png $/rep $/sho,close $/wait,2 fini/post1 esel,s,type,,2 ! CONTOUR CONVECTED HEAT etab,area,nmisc,1 etab,hfctot,smisc,2 sexp,hc_area,hfctot,area,1,-1 /ann,dele /tla,-.25,.80,Convected Heat (W/m^2) plet,hc_area /sho,png $/rep $/sho,close $/wait,2 esel,s,type,,3 ! CONTOUR RADIATED HEAT etab,area,nmisc,1 etab,hrtot,smisc,3 sexp,hr_area,hrtot,area,1,-1 /ann,dele /tla,-.25,.80,Radiated Heat (W/m^2) plet,hr_area /sho,png $/rep $/sho,close $/wait,2 alls ssum ! NET CONVECTED + RADIATED HEAT SHOULD BE 5W *get,t_srfc,node,2,ttop ! EXPECTED RADIATED POWER (W/m^2) qr_nom=(5.67e-8)*((t_srfc+273)**4 - (t_env+273)**4) **** Entered By: swescott @ 04/28/2006 05:31 PM **** |
||
|