Rotating Disc Transient-Thermal-Structural

[KOTS]

Hello,
I am looking for some help in setting up an analysis as follows:

I have a rotating disc with a thermal load applied to a rectangular area offset to one side of the disc's face, the disc if then radiatively cooled whilst it rotates at a given speed.

I use workbench v14.5 regularly for simpler coupled non moving thermal-structural analysis regularly but this is a little beyond me and I don't have any experience with ADPL programming (yet) which I assume is required?

Many Thanks

Paul

 

[rickfischer51]

Hmmm. What effect does the disc speed have on radiation heat transfer? Or does "radiatively cooled" mean heat transfer in a radial direction out the OD of the disk via convection? Is the thermally loaded rectangular area fixed in space (like a disk brake) or does it move with the disk?

Rick Fischer
Principal Engineer
Argonne National Laboratory

 

[KOTS]

Hi Rick, the speed of the disc does not affect the radiation heat transfer but there will be a point that the disc is rotating at the optimum speed to maintain the lowest temperature I think?

The loaded rectangle is fixed in space like a brake disc type problem, Should note that the whole assembly is in UHV environment so it can be assumed that radiation is the main heat transfer mechanism.

 

[rickfischer51]

One way to do this would be to apply the heat with a series of tables, then pulse the heat from each table with another table. Problem is that in workbench a table applied load can only have one variable (x,y,x,t). I think it would be cleaner to run this in MAPDL. The code would look something like this:

*afun,deg
pi=acos(-1)

tinc=.01
tyme=10
ninc=tyme/tinc

rpm=1000
omega=2*pi*rpm

hh=2 ! height of rect patch
ww=4 ! width of rect patch
mr=4 ! mean radius of patch
t=1 ! disk thickness

antype,,new

*do,time,tinc,tyme,tinc
bfdele,all,hgen
angle=omega*180/pi*time
csys,1
clocal,101,0,mr,angle,t/2,-angle
nsel,s,loc,z,0
nsel,r,loc,x,-ww/2,ww/2
nsel,r,loc,y,mr-hh/2,mr+hh/2
bf,all,hgen,.....

radiation BC's here

solve

antype,,restart

*enddo


The idea here is to create a local rectangular coordinate system at the center of your rectangular patch that rotates around the global cylindrical system at your specified speed, and use this to select the nodes in the rectangular patch and apply the heat generation.

Rick Fischer
Principal Engineer
Argonne National Laboratory