Rocket engines are known for one thing above all else, and that’s getting hot. It’s this very property that makes them such a challenge to build and run from a materials engineering standpoint. It’s hard enough to build one with advanced metal alloys, but [Integza] presses on with trying to make one on a 3D printer. Progress is being made, but success remains elusive.Β (Video, embedded below.)
To try and mitigate the thermal effects of burning propellants in his engine design, [Integza] looked to vortex cooling. This is where oxygen is swirled around the outer edge of the combustion chamber in a vortex, acting as a buffer layer between the burning fuel and the chamber walls. With 3D printed chamber components, keeping temperatures as low as possible is key, after all. Unfortunately, despite using a special ceramic-laden resin for printing and lathering the rocket components in various refractory materials, it wasn’t possible to stop the chambers leaking. Solid combustion was possible for a few seconds at a time, but eventually each motor tested turned into a ball of flames as the walls broke down.
Thankfully, nobody was hurt in testing, and [Integza] has a clear idea of the problems that need to be fixed in the next iteration. We’ve featured other vortex cooled rockets before – the theory is sound. As always, the devil is in the implementation.
Learning about all the ways that *dont* work is a good way to find one that does. Often. And getting to blow stuff up is always its own reward.
Some ways he is more and Edison than a Tesla.
I was quite amazed a while back when I used a ceramic exhaust paint on a header (car exhaust manifold) and it dropped temps above it from “melting all the plug wires and clips” to not. I didn’t have an IR thermometer at the time I did this, so can only guesstimate something like a 100C drop, as ABS parts were going really gloopy and flowing, and after weren’t even sticky or malleable. It was only going to be a “first layer” before I wrapped it in fibreglass cloth and applied another layer on top, but it seemed to do the trick so well I dropped it way down the priorities and it never got done. I think it was VHT flameproof or something like that. Was a rattle can I got on clearout a year or two before, so was double amazed that it was old stock, rattle can stuff that worked. Was the silver I used. There’s some internal stuff available now also I think.
By “above it”, I thought at first you meant “upstream of the exhaust flow”…as in exhaust ports, valves, head…
B^)
If it is “Lizard Skin” brand (not making this up) then it seems to be the “small quantity and hot rodder” version of their industrial and marine product. They rate its insulation at about R1 per moderately heavy spray layer. Evidently it can be layered on forever if the coats are allowed to dry between sprayings. It’s used on supertankers to prevent water condensation and subsequent rust between the inner and outer hulls. “#vanlife” van conversion builders also use it to prevent condensation. Finally, the hotrod crowd reports it also works well on the firewall and floorboards to lower the cockpit temperature. The stuff is just pure win all the way. Oh, and its a factory finish on high grade, commercial-building-style metal roofing. Close to $100/gallon.
The method described in the paper “The Electroless Deposition of Nickel-Phosphorus-Tungsten Alloys” may be a good way of sealing porous 3D printed ceramics as well as reducing IR transmission by making the inner surface more reflective, and this will protect the goop on the outside that is going to burn no matter what if the pure O2 get to it.
Ceramics tend to be porous, and I suspect 3D printed ones, more so. The traditional solution in pottery is to vitrify the ceramic, a process that makes it water-tight. There are lots of possible glazes (https://en.wikipedia.org/wiki/Ceramic_glaze) to use, but the probably the most accessible is simple table salt. Also, maybe firing at high temperatures (above 1000C) may reduce porosity, at the cost of more shrinkage.
The key concept is vitrification, with it comes even more risk of deformation.
Try using CO2 at a lower volume instead of O2?
One would expect the O2 to induce the flames TO the walls, while a thinner layer of CO2 would push it AWAY and also insulate the chamber walls.
how is that supposed to work? where does the oxidiser come from is you use co2 instead of O2?
also if you watched his previous videos you would know that his full resin vortex rocket didnt melt only the nozzle did proving the temperature inside the chamber is not the problem only air tightness is an issue.
I’m saying to add the tangential input be completely, but the axial input could still be air.
You could literally design it as a vortex tube, and the O2/CO2 components would stay separate in the chamber.
Tang input as pure CO2, axial input regular atmosphere.
Why not use a service that 3D prints in metal?
Do you know of one that is affordable?
In this particular case: because he runs a DIY youtube channel.
But if you’re not interested in doing it yourself, having someone else do it for you is clearly an option. :)
Anti gravity crafts do exist….. they are called Rockets
I bet that if he coated it with a good layer of tomato sauce it would work like a champ.
He’ll have to check with Tomato Lord Jr…
[Non-nice post, ranting against 3DP as a reasonable way to create a rocket engine.]
I would guess that a paper mache rocket engine would hold up nicely for more than 10 seconds… You would need really many layers and enough time to dry in-between – but why not?
Paper mache made from phenolic resin and carbon nanotube paper will, once it is pre baked in an inert atmosphere, stand up to very high temperatures, but the oxidation is always going to be a problem that ceramics does not have, given they are formulated from oxides. So you could coat the carbon-carbon “mache” structure with hafnium oxide to prevent that. And if you are thinking that sounds like rocket science, well yes it is. :-)
Use the product the way it’s intended, people complain “It’s not a hack”. Use the product on the most unsuitable way “just because I can” and it’s labelled as garbage that needs to stop.
Let them be happy printing a rocket engine with butter! I have fun watching, and that’s enough for me.
Is 3d printed ceramics not meant for rocket like environments? Im certain I saw rocket nozzles in the marketing material for these ceramic 3d printers.
[counter-rant]
Integza is trying to entertain, and he’s doing it very well. His videos are fun to watch.
It wasnβt an FDM printer. It was a resin printer… using silica ceramic.
But please, keep being sanctimonious.
“… using a special ceramic-laden resin…”
He’s not using plastic and on the surface, the material (once properly post processed) seems perfectly suitable from a thermal standpoint.