Verdrängungskreiselrotor d132|17
Working on a centrifugal displacement hybrid pump, for the rotor (∅ 30mm) i made my first print (PETG) with only 50µm Layer (0.05mm) … I like the result (0.5 nozzle). Two Parts — took about 20min.
Question: will the texture on that surface make it pump better or worse ? Neat idea !
@Dave_Baehr
Depends on the RPM and the viscosity of the fluid to be pumped, and the geometry of the twmexture.
Cavitation is a pumps worst enemy, and the texture might tend to create cavitation at lower RPM.
If the RPM is too low for cavitation to be an issue, then you’re just looking at laminar flow on the part surface which can be affected by the texture, so some sort of top coat or polishing might improve the performance of the pump.
Seems like a good candidate for ABS with acetone vapor smoothing.
@Dave_Baehr normaly a smooth surface should be prefered as everything rough would cause turbulence hence engergy is lost. At least the layer structure is axial to the flow not perpendicular. A microstructure with placoids would be great but that is nothing i can do at the moment. https://upload.wikimedia.org/wikipedia/commons/f/fa/Denticules_cutanés_du_requin_citron_Negaprion_brevirostris_vus_au_microscope_électronique_à_balayage.jpg
@mark_warlick i assume you meant at higher RPM (higher pressure difference) cavitation could be an issue. In my design the pressure within the pump should rise with the diameter and in theory that could minimize cavitation. As i am not rely solely on centrifugal force the pump doesn’t need high RPM. Probably all these are not that importand at the small scale as the reynolds nr is small.
@Ulrich_Baer
Well, I suppose the point is to experiment with the geometry.
It’s a very interesting geometry too.
I’m interested to see what the housing will look like.
You must intend to have very low clearance, in which case you’ll run into hydraulic shear eating into your torque budget.
It looks like you intend to have a dual input and a single output.
Where I work, we buy about 11,000 pumps on that scale per year, if that motor is the size I think it is.
We use them to deliver cleaning fluid to our windshields.
We don’t pay much for them, or expect much out of them except sufficient throughput and durability.
The impellers are injection molded.
The motors are 12v DC.
Do you intend to scale that one up at some point?
Do you have an application in mind?
If you don’t, I do.
Not windshield fluid either.
@mark_warlick you can see the 1st prototype design here https://plus.google.com/u/0/+UlrichBaer/posts/CvHqnPyYuvK the working principle is shown here https://plus.google.com/u/0/+UlrichBaer/posts/XQvgMZcD4xE … and Yes you are absolutly right about clearance and hydraulic shear , stator and rotor are just .1mm appart (one is sliding onto the other). But i convert it into movement - the fluid can stay in place and will be pushed out by the rotor, or it start to rotate and then will be pushed by the stator. In both cases the hydraulic shear will be max, so the fluid will try to stay between these max options. The first model was ∅60mm, now iam trying bit smaller as i like to get the redirector around (this https://plus.google.com/u/0/+UlrichBaer/posts/aaxuZ8oChps ) The basic idea was a powerjet to drive a boat … like a VSP (cyclorotor) but much simpler and smaller - it could run in a puddle and will not harm fish - could be on a outboard motor aswell. Without the redirector you get a flat wide stream which could integrate well into an hydrofoil…
@Ulrich_Baer
Oh my,…
That’s a bit fancier than I was thinking.
Elegant too.
I’m thinking that you should go bigger, and make a casting that will handle some horse power.
Looks like a thruster for a tug boat to me.
@mark_warlick Thanks, and yes if i have a final design - scaling it up should be easy - my bath tub experiment also suggest that with the right nozzle this could power a speedboat. Or maybe just push honey onto my bread 
maybe i really should test viscous fluids, maybe this could build up enough pressure to work as an hydraulic pump. But first keeping things small also keeps cost low and printing time. And it gives me the chance to understand the characteristic better.
@Ulrich_Baer
We pump a lot of automotive paint.
The equipment is fantastically expensive and complex.
I like simple.
@mark_warlick pump for transport it or to get it out an airless nozzle and spray? … i am pretty sure that at least transport would work – cleaning could be a problem but as the parts could be made via injection molding (extruded 2D) you could have a onetime pump and after the job you just change the rotor and stator for a newone … if made from POM, PC or PU it is probably paint resistant enough.
Mine looks like that, i have 0.3mm nozzle
@Ulrich_Baer
I might also know how to apply your concept to simplify some complicated solutions that I won’t mention in an open forum.
@mark_warlick please feel free to contact me directly.
@mark_warlick Will a windshield washer pump handle 100% duty? As in, can it be used to pump water in small hoses for water cooled hotend?
@Daniel_Kruger
I don’t know.
I don’t think the ones I use could, but I’ll ask our testing group if you remind me.
They make a nice stealthy squirt gun though.
If you can get one thats made for a high end automobile, I think it well might, but try a cheap one first.
I’ve never seen one fail on a Honda or Toyota, and the duty life is quite harsh for those, and I don’t hear anything about warranty claims on ours, though we have customers from Columbia to Saskatoon.
In any case, they can be had cheaply.
Get two and see what happens.