3D Printing A Water-Cooled Jet Engine?

Everybody knows the trick to holding a candle flame to a balloon without it bursting — that of adding a little water before the air to absorb the heat from the relatively cool flame. So [Integza], in his quest to 3D print a jet engine wondered if the same principle could applied to a 3D printed combustion chamber. First things first, the little puddle of water was replaced with a pumped flow, from an external reservoir, giving the thin plastic inner surface at least a vague chance of survival. Whilst this whole plan might seem pretty bonkers (although we admit, not so much if you’ve seen any of other videos in the channel lately) the idea has some merit. Liquid cooling the combustion jacket is used in a great many rocket engine designs, we note, the German WWII V2 rocket used this idea with great success, along with many others. After all, some materials will only soften and become structurally weak if they get hot enough in any spot, so if it is sufficiently conductive, then the excess heat can be removed from the outer surface and keep the surface temperature within sensible bounds. Since resin is a thermoset plastic, and will burn, rather than melt, this behaviour will be different, but not necessarily better for this application.

The combustion chamber itself didn’t burn

The issue we can see, is balancing the thermal conductivity of the resin wall, with the rate of cooling from the water flow, whilst making it thick enough to withstand the pressure of combustion, and any shock components. Quite a complicated task if you ask us. Is resin the right material for the job? Probably not, but it’s fun finding out anyway! In the end [Integza] managed to come up with a design, that with the help of a metal injector separator plate, survived long enough to maintain some sort of combustion, until the plate overheated and burned the resin around its support. Better luck next time!

This isn’t the first time attempting to use 3D printed resin for such an application, here’s an attempt to use the air-multiplier type setup with a combustion chamber. Of course making a combustion chamber from a toilet roll holder is far more sensible, just as [colinfurze] will attest, don’t try this at home folks!

14 thoughts on “3D Printing A Water-Cooled Jet Engine?

  1. Rocket engines usually duct the fuel or oxidizer through the jacket surrounding the combustion chamber to keep it cool. Not water… carrying water for that purpose would be rather inefficient, no?

    1. To be fair, he did try cooling it with liquid butane… And it went as well as expected. Ducting is a necessity, and he just had a large chamber wit a significant air gap.

      1. I think butane was wrong even from a fundamental perspective: it’s garbage at conducting heat, like 0.1 W/mK versus water’s 0.6 W/mK. Even though it’s a bit colder I don’t think it’s able to pull the heat off the plastic. It’s also got a lower heat capacity, but I doubt that matters since there’s probably nowhere near enough time to absorb that much heat.

  2. 3d printing enthusiasts?!

    You don’t know anybody with a lathe? Your shape is simple, not a good candidate for 3d printing.

    If you must 3d print something, print an ablative liner for your metal combustion chamber.

    Also does he even LOX? Compressed air?

    I hope that top shot with with a long lens and he isn’t really that close. I don’t think he even has on safety squints.

    For ref: My planned last thought…’at least I’m not on fire…’

    1. You are completely missing the point, it is more to see if it is possible than doing serious design work, sure he could find someone the machine it but that’s not the point. Not everything needs done in the most optimal way, especially when experimenting.

      1. I agree with haha, he’s basically just making badly designed, non-functional and dangerous toys based on old

        The outlandish and ridiculous project titles are purely for the youtube views, and most engineering logic and good practices goes right out of the window. Who needs to make something that actually works if you can make thousands from people watching you making useless crap.

        Sure it’s briefly entertaining but ultimately a waste of time, materials, energy and effort.

    1. And now you also know you can boil water in a plastic by holding over a flame\fire and the bottle will not melt. A survival tip since you can find plastic trash all over if you find yourself in need to boil water before drinking it.

      You can also put a bit of stick tape on a balloon and prick it with a needle and it won’t pop.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.