Discussion Forum

I am using 4.3 and have selected "form an assembly" as opposed to "form a union" for the Finalization Method.

Hi

The easiest way to model a pipe in COMSOL is to draw a rectangle and add an upper and lower layer of the tube thickness. But be aware that in 2D it's not really a "pipe" but two plates infinitely long in the out-of-the-paper direction (Z)

in 2D axi it's a rectangle going along the vertical axis direction with a layer on the right side.

And in 3D it's a cylinder with a radial layer of the tube thickness, and desired tube length.

For complex shapes, you can draw a 3D line (tube centre, and add two circles at one edge, then sweep these along the line. But often a CAD software is better suited for very complex geoemetries.

You can also model a pipe, filled with a liquid as two concentric cylinders giving you the pipe wall and the fluid domain, once "Finished"

finally if you do not have the flud volume, only the pipe volume, there is the new "cap ends" feature in v4.3 geoemtry, to create the fluid volume from hollow tubes, by capping the end edges

If the pipes are "long" then the "pipe flow physics module" is of interest, there pipes are "lines" 1D elements and the flow is simulated via lumped equations considering the pipe area

So there you are, pls choose, there are "many ways to Rome" as one say ;)

--
Good luck
Ivar

Brad, that is surprising. If the SolidWorks part is internally partitioned into pipe and fluid space that partitioning should import in COMSOL.

Hi all,
I would like to ask you how correctly implement a tube into COMSOL in order to simulate laminar fully developed fluid flow (first part) and heat transfer in the tube from the fluid (second part). I have tried to make a livelink between COMSOL and Solidworks, to draw a tube in COMSOL. I have used 3D, 2D and 2D axisymmetric geometries for all the problems. I cannot make it to work correctly. I mean, with 3D tube I get fully developed flow profile as being in between two infinitely long plates. I have to use 3D modelling since I have very complicated and not symmetrical geometry.
For the heat transfer problem , I have used conjugated heat transfer for laminar flow. I am struggling how to set boundary conditions properly that COMSOL would give me reasonable results. I wan to simulate the copper tube with the laminar water flow inside. The temperature at the inlet and ambient temperature is known, I want to find heat flux through the tube wall.
Could you please advise me how to deal with COMSOL for this?
Thank you in advance.

Hi if anybody have laminar flow ,level set problem in 3D example? I m looking for that to prepare my model!

Hi;
i also have the same proplem i try to simulate 3D fluid inside pipe and want to study fluid temperature effect on wall thickness of pipe in comsol you need no simulate fluid and the just choose the wall and select type of equation for flow, and then comsol will simulate fluid as it is inside pipe.
but what if i want to draw full wall thickness of pipe complete with fluid and study the heat transfer in wall thickness how we can do this?

i attach pic for my project, you can see thickness not influance with fluid temperature i dont know why?!, any ideas?
i form an Union in geometry