mcad bridge import and export, velocity inlet b.c
 

Hello,

1) I am facing a problem while importing geometry to mcad bridge. I draw it in autocad 2015, export it to .igs file and when I try to import it with FLOMCAD Bridge 10.1 I get weird results - entities in my drawing are rearranged (f.e. If I draw a rectangular duct with a cylinder on top of it and a small rectangle on top of a cylinder, the duct moves away from the rest). When I exported .dwg into .stl file and loaded it in mcad bridge I didn't get any geometry at all.

2) I don't know how to export stuff from mcad bridge to flotherm, when I go to Transfer Assembly tab is blanked, I couldn't find any reference to it in user's guide, or ocumentation.

3) I would also like to ask if there is a way to specify velocity profile at the inlet to a duct - is there anything like udf from fluent.

Thanks in advance ;)

hello,
1) try exporting as *.stp (STEP file) or *.sat (ACIS SAT file). Try to make it simple so MCAD won't crash at opening it. Also, the XYZ system coordinates must be arranged in the corner of the rectangle (you'll see later why). Hint: make one part at a time and import it into MCAD (not all in a big model).
2) before transferring the assembly you have to convert your CAD into recognizable flotherm format (cuboids, prisms, cylinders, sloping blocks...etc). To do this use "tools" tab: "voxalize" and "dissect body" are usefull (read in the help about). For voxalize it's efficient to have the system coordinated parallel with the faces of the rectangle (see above) ;) When you original CAD is "transformed" into flotherm parts color changes to dark blue.
After each of you original CAD is converted you can hit "Tools" -> "Transfer Assemblies" to have the geometry in flotherm project tree.
3)to specify inlet, outlet speed you could use "fixed flow"...etc. Here it depends on the simulation...etc.

Are you sure fth is suitable for your CFD needs? :confused:
Best regards, Gabriel

Hello Gabriel,
thank you very much for the help - .stp exporting seems to be working fine ;)
However I still cannot hit "Transfer Assemblies" button. Everything is dark blue, model is really simple, and I don't know what am I doing wrong.

I also do not understand your last question because of the "fth" word. If you are asking if i need paraboloidal velocity profile at the inlet, the answer is that I don't know, I wanted to investigate effects. I can also check for the heat transfer coefficients in the literature, but I think those are applicable only in simple cases.

Hello,

1. fth = Flotherm
2. follow these steps:
a. open flotherm !!!
b. open MCAD (from flotherm: go to Window -> Launch FloMCAD Bridge)
c. import just a cube (*.stp made in your CAD software)
d. click to select the cube in FloMCAD
e. Tools -> Single object... -> OK
f. Tools -> Transfer Assembly.

If all those simple steps don't work... send me a private message so we can exchange e-mail address and exchange files. :)

Best regards, Gabriel

ok it works, thank you very much!

I knew I was doing some basic mistake, which was starting flomcad bridge and flotherm independently.