How to model furnace coils

[Crusader911]

I'm working on a line that's coming out of the radiant section of a furnace. Since the nozzle is not restrained, I have to model some of the coils in order to have a decent anchor point. The piping is bent in a helical coil with about 12 rings. the coil is supported by u-bolts, 4 per ring. My questions are:

1. How do I model the bent piping? I recall doing this once before for a line that made a long curve around a storage tank. I put in many small-angle elbows and did a polygon approximation. Is there no better way?

2. How many rings do I need to include to get an accurate boundary condition?

 

[DSB123]

Crusader,
"Model" the pipework as it is physically. If you compromise on your "modelling" you get compromised results. On the second point, model sufficient of the rings to ensure that the coils you do not model have no effect on the results. Simple eh!!

 

[Crusader911]

I get it to look right-but I get errors because there's not enough downstream length to contain the bend curvature. Someone on another forum suggested eliminating every other bend, but I haven't tried that yet.

 

[richay]

For an example of a coil model, e-mail techsupport@coade.com and ask for the "COIL" model.

Richard Ay
COADE, Inc.