Everyone knows the trick of lighting a candle flame on a balloon without bursting it – adding a little water in front of the air to absorb the heat of a relatively cold flame. Therefore, in his quest for 3D printing, a jet engine wanted to know whether the same principle could be applied to the combustion chamber of 3D printing. First, the small puddle was replaced by pumped water from an external reservoir, which gave the thin plastic inner surface at least a vague chance of survival. Although the whole plan may seem crazy (although we admit that if you’ve seen any other videos on the channel recently, it won’t be so crazy), the idea has some value. Liquid cooled combustion jackets have been used in many rocket engine designs. We note that the German World War II V2 rocket, like many other rockets, successfully used this idea. After all, some materials will soften only when the temperature anywhere is high enough, and the structure will become weak. Therefore, if the material has sufficient conductivity, the excess heat can be discharged from the outer surface and the surface temperature can be kept within a reasonable range. As the resin is a thermosetting plastic, it will burn rather than melt, so this behavior will be different, but not necessarily better for this application.
The problem we can see is to balance the thermal conductivity of the resin wall and the cooling rate of the water flow, while making it thick enough to withstand the combustion pressure and any impact components. If you ask us, this is a rather complicated task. Is resin the right material for this job? Maybe not, but anyway, it’s fun to find out! Finally, [integza] managed to come up with a design, that is, with the help of the metal injector diaphragm, it can survive long enough to maintain a certain kind of combustion until the diaphragm overheats and burns the resin around the support. Good luck next time!
This is not the first attempt to use 3D printing resin for such applications. Here, an attempt is made to set the air multiplier type for the combustion chamber. Of course, it is much wiser to make a combustion chamber with a toilet paper holder. As colinfurze proved, don’t try this method at home!