Heat Exchanger with spline path

[Britt007]

Hi,

I'm trying to build a model of an heat exchanger, I'm using bend modifiers and arrays as the pictures below show, but what I'd like to do if possible is build a complete path like a spline path in the shape of the heat exchanger and extrude a circle along it to build one complete pipe, that is because if I want to make a change as it is say to the cylinder radius, and or the shell thickness I then have to alter other things to bring the separate parts to align with each other, and I thought if I could do it the other way it would be easier to make changes without the problems of re-aligning the different parts, any help would be greatly appreciated.

Kevin.

 

[frank beckmann]

Not saying it´s impossible, but connecting end nodes of Splines isn´t fun. I´d build this thing from a half Torus; copy and paste, rotate 90°/180°, snapping to components, bridge tool, (Array/Symmetry modifiers) etc. That´s fun to me:

Déjà-vu: https://www.cheetah3d.com/forum/index.php?threads/14284/

 

[Helmut]

* As I have mentioned in the Déjà-Vu reference quoted by Frank B, this is primarily a stack (array / symmetry) of identical components.
* You need to generate a precise spine for one "level" of the heat exchange tubes and build on that.
* In the sweep creator you can easily tweak the profile (diameter of the pipe) and the subnodal shell (thickness of the pipe).
* Getting a clean base spline is a bit fiddly, the rest is trivial.

 

[ZooHead]

I agree with my fellow C3d users, Franks way is more quick and fun but if you must do the spline thing, it is doable.
I started with a Circle Spline, and selected a point and used Spline/Break Segment to break it into two half circles.
From there use Spline/Join Segment and rotate to change directions.

Here's two larger segments being joined to make one level as Helmut stated.
If it connects improperly, use Spline/Reverse Sequence on one segment.

 

[frank beckmann]

Pipe mesh diameter can be altered via Normal Move:

 

[frank beckmann]

@ZooHead Are the Spline segments really connected or just snapped in place?

 

[ZooHead]

All connected.

 

[ZooHead]

Cheetah even lets me join multiple sections at once.

 

[frank beckmann]

Mmh - I tried to join half of a circle with a straight spline (direction token into account) but no luck - I always can pull one end node from the other. Geometry looks ok though.

 

[ZooHead]

Here's what I'm doing:

 

[Britt007]

Thanks a lot everyone for your input, helped a lot, much appreciated

 

[Britt007]

Hi it's me again, ZooHead Ive been making the spline paths and joining them together like you described but the last few won't join with each other, I've corrected some of their orientations as they were trying to connect to the wrong side of the next spline path, I have 9 layers to my heat exchanger, the firs layer I have taken the splines out of their transform, that is the layer I've been trying to connect all the splines together, could someone take a look at my project and tell me what I'm doing wrong please, I'd really appreciate it, thanks.

 

[ZooHead]

Looks like a few mistakes with the splines construction need to be fixed.
There may be more than I'm showing, you need to alter your method a bit.
Here's a tip: Don't bother using Spline Lines, the Join command does that for you.

Think of the Join command like the Bridge command for splines,
it will always add a spline section between the ends of the sections you are joining.

 

[ZooHead]

Here's an alternate way to set this up.

 

[ZooHead]

I broke it down a little further here to show a version closer to what you've shown.

 

[Britt007]

I broke it down a little further here to show a version closer to what you've shown.

View attachment 39767

Hi, that's what I've been trying to do, I think I'm getting there thanks to your help, what I can't get is joining each layer to the next one, so for now I'm just sweeping each level, and I think I've got the end straights twisted as you can see from when they are swept, but I'll keep trying, and learning, thanks again for your help.

 

[Helmut]

* Returning to the original concept as shown in the deja vu thread:
* The cylinder + bend concept is now replaced with a sweep on a spline.
* I am using here a single basic element, a pipe shaped as a J, equal a quarter-circle plus linear rise. This is just a sweep on a J-spline.
* The rest is just a set of symmetries and arrays.
* The sample shows an exchange with 9x6 layers as in your model on top of this thread.

* To edit the diameter: select all circles in the object browser and replace (just once, the new parameter is applied to all)
* To edit the thickness: select all shells in the object browser and replace (just once, is applied to all)
* The size / complexity of the heat exchange can be easily modified by in- / decreasing the items in the horizontal / vertical array.

 

[Britt007]

* Returning to the original concept as shown in the deja vu thread:
* The cylinder + bend concept is now replaced with a sweep on a spline.
* I am using here a single basic element, a pipe shaped as a J, equal a quarter-circle plus linear rise. This is just a sweep on a J-spline.
* The rest is just a set of symmetries and arrays.
* The sample shows an exchange with 9x6 layers as in your model on top of this thread.

* To edit the diameter: select all circles in the object browser and replace (just once, the new parameter is applied to all)
* To edit the thickness: select all shells in the object browser and replace (just once, is applied to all)
* The size / complexity of the heat exchange can be easily modified by in- / decreasing the items in the horizontal / vertical array.

View attachment 39772

Hi Helmut, thank you for your input, much appreciated, what I've done is scaled your model to what I would need in the real world as this would be resin printed so the tubes just need to sit on each other as to not need supports and to optimise the space, but now I can't add a shell, as I need a shell of 0.1 but it just explodes out of the tubes, could you tell me why this is happening please? I've tried tweaking the diameter of the circles but can only add a shell if the diameter of the circles are smaller than what I need, I've attached the amended project, thanks.

 

[frank beckmann]

Perhaps give the "X-section" a thickness by using 2 circles as a compound path:

 

[Helmut]

* Some more tweakery and we may be getting there.
* I have to solve some spikey artefacts on the elbow of the vertical inflow / outflow.
The rest looks OK to me with a 0.1 shell.
PS: Sorry, this is not 6x9 but 7x9 layers.