Probably be one of the first things my new printer will be used for when it comes in. Guess I should get with it and order it huh? Lol.
IIRC, Beaver got interesting flow numbers using something I sketched up a while back. https://rcwarshipcombat.com/resources/3dp-single-unit-pump-restrictor.80/
its not an ideal application for a thermoplastic 3dp w\o being chased by the appropriate tapers, reams and then regularly checked for wear. I wants me some metal parts.
It may actually be better than you think. The roughness on the outlet can prevent flow separation that when it occurs you loose the diverging half.....
FYI, when I make my nozzles I use a small scissors blade to ream out the tapers. Just make sure you leave enough material in the center, say 1/8"-1/4", that you can drill out the restrictor. Once done, give it a wipe of acetone to strengthen it and it's good to go!
For gory details see the handbook of hydraulic resistance by idelchik. The short of it is that roughness mixes the boundary layer, pulling high momentum fluid towards the wall. This helps prevent flow separation caused by the adverse pressure gradient in the diverging section. While you increase the pressure drop over a purely ideal nozzle, in practice you can end up with a better all around design and/or a much shorter diverging section with less risk of it not functioning the way intended....
1 unit IRCWCC legal, preferably needs to mate up with a line from a BC pump, whose dimensions are currently unknown to me (just ordered it). No idea on inlet and outlet IDs or taper angles sadly, lacking the tooling to machine such I haven't really paid attention to what people have suggested as ideal.
The next time I have the lathe pulled out I'll machine a couple out. Been wanting to try one of these on the Barham anyway. Anybody know the tubing that ships with the BC pump (ID and OD)?
