Small Steam Generator Creates Educational Experience

Steam turbines have helped drive a large chunk of our technological development over the last century or so, and they’ll always make for interesting DIY. [Hyperspace Pirate] built a small turbine and boiler in his garage, turning fire into flowing electrons, and learning a bunch in the process.

[Hyperspace Pirate] based the turbine design on 3D printed Pelton-style turbines he had previously experimented with, but milled it from brass using a CNC router. A couple of holes had to be drilled in the side of the rotor to balance it. The shaft drives a brushless DC motor to convert the energy from the expanding steam into electricity.

To avoid the long heat times required for a conventional boiler, [Hyperspace Pirate] decided to use a flash boiler. This involves heating up high-pressure water in a thin coil of copper tube, causing the water to boil as it flows down the tube. To produce the high-pressure water feed the propane tank for the burner was also hooked up to the water tank to pressurize it, removing the need for a separate pump or compressed air source. This setup allows the turbine to start producing power within twelve seconds of lighting the burner — significantly faster than a conventional boiler.

Throughout the entire video [Hyperspace Pirate] shows his calculation for the design and tests, making for a very informative demonstration. By hooking up a variable load and Arduino to the rectified output of the motor, he was able to measure the output power and efficiency. It came out to less than 1% efficiency for turning propane into electricity, not accounting for the heat loss of the boiler. The wide gaps between the turbine and housing, as well as the lack of a converging/diverging nozzle on the input of the turbine are likely big contributing factors to the low efficiency.

Like many of his other projects, the goal was the challenge of the project, not practicality or efficiency. From a gyro-stabilized monorail, to copper ingots from algaecide and and a DIY cryocooler, he has sure done some interesting ones.

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British Trains To (Maybe) Make Way For Steam Once More

There’s nothing more guaranteed to excite a grizzled old railway enthusiast than the sight of a steam locomotive. The original main-line rail propulsion technology still clings on in a few places, but for practical purposes, it disappeared a lifetime ago. It’s interesting then to hear of a brand new steam locomotive prototype being considered for revenue freight use on British metals. Is it yet another rebuild of a heritage design to be used for enthusiasts only? No, it’s an entirely new design with nothing in common with the locomotives of the past, as [Terrier55Stepney] tells us in the video below the break.

Gone is the huge boiler and reciprocating pistons of old, as indeed is the notion of boiling anything. Instead, this is a steam turbine, nothing like the 1920s and 30s experiments with conventional locomotives, nor even the Union Pacific’s oil-fired condensing turbo-electrics. The new idea here from the British company Steamology is to create steam directly from the combustion of hydrogen in a series of small modular steam generators, and the resulting prototype turbo-generator will replace the diesel engine in a redundant British Rail class 60 freight locomotive. It’s unclear whether it will incorporate a condenser, but since it has no need to retain the water for a boiler we’re not sure it would need one.

Prototype locomotives featuring new technologies have a long and inglorious history of not making the grade, so while this is definitely an exciting and interesting development we’re not guaranteed to see it in widespread use. But it could offer a way to ensure a low-carbon replacement for diesel heavy freight locomotives, and unexpectedly provide engine upgrades for existing classes. The fact it’s technically a steam locomotive is incidental.

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3D Printed Parts Hold Up To Steam Heat

Steam turbines are at the heart of all manner of industrial machinery, particularly that used for power generation. [Integza] decided he needed to better understand this technology, and decided to build one himself – using 3D printing, at that. 

First, a steam source was needed, with a pressure cooker on an electric stove pressed into service. The steam was passed out via a nozzle printed in resin, which better resists heat than most FDM-printed parts. Similarly, a turbine wheel was printed in resin as well, with the steam outlet pointed directly at its vanes.

To really stress test the parts, more steam was required.  To achieve this, hydrogen peroxide was pumped through a manganese dioxide catalyst impregnated into steel wool to create steam. This made an absolute mess, but the printed parts nevertheless survived.

The steam turbine didn’t do any useful work, but was able to survive the high temperatures at play. We’d love to see such a device actually used to bear some load, perhaps in some sort of 3D printed power generating turbine design.

Alternatively, if you prefer your steam turbines more classically driven, consider this build. Video after the break.

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