More than Two Materials in Enclosures - How to Model?
More than Two Materials in Enclosures - How to Model?
(OP)
I have several enclosures in my model that have more than 2 materials - each with different emissivities. I was wondering what the appropriate means of modeling this is. I've tried the general radiosity solver, but I get the following error when I try to input more than two radiating surfaces in an enclosure:
My input is below. Any suggestions? Thanks in advance for the help.
Quote (ANSYS):
*** ERROR *** CP = 227.219 TIME= 15:59:34
The Nlist field of ( RAD_ ) on the SF command is invalid. Only the
labels of ALL,blank,P,P51x, or a COMPONENT name are allowed. The SF
command is ignored.
My input is below. Any suggestions? Thanks in advance for the help.
CODE
/prep7
sf,RAD_SURF_1A,rdsf,0.200,1 ! Nickel 0.05-0.86, (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_1B,rdsf,0.200,1 ! Nickel 0.05-0.86, (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
spctemp,1,850
sf,RAD_SURF_2A,rdsf,0.535,2 ! Zirconium (0.62-0.45), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_2B,rdsf,0.441,2 ! Type 304SS (http://www.nordicinnovation.net/nordtestfiler/rep570.pdf)
sf,RAD_SURF_2C,rdsf,0.150,2 ! Aluminum (0.11 - 0.19), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
spctemp,2,134
sf,RAD_SURF_3A,rdsf,0.200,3 ! Nickel 0.05-0.86, (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_3B,rdsf,0.535,3 ! Zirconium (0.62-0.45), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_3C,rdsf,0.950,3 ! Microsil Insulation (http://www.zircarceramics.com/pages/microporusinsulation/microporous.htm)
sf,RAD_SURF_3D,rdsf,0.900,3 ! Fiberfrax, (http://www.fiberfrax.com/files/Fiberfrax-Durablanket-Mat.pdf)
sf,RAD_SURF_3E,rdsf,0.150,3 ! Aluminum (0.11 - 0.19), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_3F,rdsf,0.001,3 ! Blockoff Shells
spctemp,3,29.04
sf,RAD_SURF_4A,rdsf,0.535,4 ! Zirconium (0.62-0.45), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_4B,rdsf,0.400,4 ! Nickel 0.05-0.86, (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
spctemp,4,950
sf,RAD_SURF_5A,rdsf,0.150,5 ! Aluminum (0.11 - 0.19), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_5B,rdsf,0.535,5 ! Zirconium (0.62-0.45), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_5C,rdsf,0.950,5 ! Microsil Insulation (http://www.zircarceramics.com/pages/microporusinsulation/microporous.htm)
spctemp,5,150
stef,5.67e-8
toffst,273.15
hemiopt,10
tunif,500
/solu
rsymm,,0,y
rsymm,,0,z
rsurf
sf,RAD_SURF_1A,rdsf,0.200,1 ! Nickel 0.05-0.86, (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_1B,rdsf,0.200,1 ! Nickel 0.05-0.86, (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
spctemp,1,850
sf,RAD_SURF_2A,rdsf,0.535,2 ! Zirconium (0.62-0.45), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_2B,rdsf,0.441,2 ! Type 304SS (http://www.nordicinnovation.net/nordtestfiler/rep570.pdf)
sf,RAD_SURF_2C,rdsf,0.150,2 ! Aluminum (0.11 - 0.19), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
spctemp,2,134
sf,RAD_SURF_3A,rdsf,0.200,3 ! Nickel 0.05-0.86, (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_3B,rdsf,0.535,3 ! Zirconium (0.62-0.45), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_3C,rdsf,0.950,3 ! Microsil Insulation (http://www.zircarceramics.com/pages/microporusinsulation/microporous.htm)
sf,RAD_SURF_3D,rdsf,0.900,3 ! Fiberfrax, (http://www.fiberfrax.com/files/Fiberfrax-Durablanket-Mat.pdf)
sf,RAD_SURF_3E,rdsf,0.150,3 ! Aluminum (0.11 - 0.19), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_3F,rdsf,0.001,3 ! Blockoff Shells
spctemp,3,29.04
sf,RAD_SURF_4A,rdsf,0.535,4 ! Zirconium (0.62-0.45), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_4B,rdsf,0.400,4 ! Nickel 0.05-0.86, (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
spctemp,4,950
sf,RAD_SURF_5A,rdsf,0.150,5 ! Aluminum (0.11 - 0.19), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_5B,rdsf,0.535,5 ! Zirconium (0.62-0.45), (http://www.omega.com/temperature/z/pdf/z088-089.pdf)
sf,RAD_SURF_5C,rdsf,0.950,5 ! Microsil Insulation (http://www.zircarceramics.com/pages/microporusinsulation/microporous.htm)
spctemp,5,150
stef,5.67e-8
toffst,273.15
hemiopt,10
tunif,500
/solu
rsymm,,0,y
rsymm,,0,z
rsurf





RE: More than Two Materials in Enclosures - How to Model?
Gee, in that context the error message makes sense, eh?
Well, if anyone needs an example of using the radiosity solver in ANSYS, see above.
Step 1: Define radiating faces as nodal components (i.e. named selections)
Step 2: Apply radiation using the SF command; set the emissivity and the associated enclosure for each surface
Step 3: Set the space temperature for the solver to radiate to through any holes or in the enclosure (can also use SPCNODE)
Step 4: Set the Stephan-Boltzmann constant, offset to absolute zero, hemiopt, and tunif.
Step 5: Enter solution, create symmetry conditions if they exist or decimation if desired, and mesh the surfaces with SURF252 elements.