Homebrew Traveling Wave Thermoacustic Engine

[booman809]

Hey im new to this forum and ive been super interested in Thermoacoustic engines and wanted to make a taveling wave type loop for fun but having a hard time starting it up. Is my steel wool and wet paper towel placement wrong? would love any tips or sentiments of wrong doing

[Fool]

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I'm bumping this thread. It is a valid help question by a new poster on a new version of engine. It looks like it got caught in the spam onslaught and didn't stay visible for long.

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[Fool]

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I don't know if I can help much. Your engine principal is new to me. I can describe the idea for some other engines. Try doing a search on 'laminar flow engine'. Or 'fluidyne engine'. They often go by other names, acoustic, thermal lag, pop pop boat, ...

Also there are pulse jets, valve less pulse jets, jam jar pulse jets, I've even seen wood powered valve less pulse jet.

The goal of all those is to set up a resonance with the hot and cold spaces. In the case of the pulse jets the outside air is the cold space, and new cool air is brought in to supply oxygen to the fuel. The pop pop boat brings in cool water to flash again into steam in the hot tube/boiler.

The laminar flow engine has a constrictor tube between outside and inside to speed up the velocity and slow the frequency. Yours may need something like that. It also may need a closed end to form a tuned chamber.

A fat hot chamber connected to a fat cold chamber by a skinny capillary tube between them, but not too skinny. It could be as simple as a smaller tube slid into the current one. Both the hot and cold chambers could have a thermalizer/regenerator/stainless steel wool I them. Placement and density could be very important.

Yours appears to have openings on both ends of the hot and cold spaces. It could work if the hot space were big enough and the flame were big enough.

I would try blocking the left side of the glass tube near the PVC , put in a constriction between the hot left space and the cold right space. It could be as simple as a smaller tube slid into the current glass tube. Then heat it with a bigger torch if needed, not too hot. Could melt the glass.

https://m.youtube.com/watch?v=q-n7mzCjzU4

https://en.m.wikipedia.org/wiki/Thermoa ... eat_engine

https://en.m.wikipedia.org/wiki/Fluidyne_engine



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[tom-rock]

Hi, looks very nice, thanks for sharing.

It is very similar to my new engine, I think the concept is very promising as I hav much problems with friction and wear with my kinematic engines.

Here is a link to a Youtube video of my thermoacoustic engine:

https://youtu.be/ySnDT01dIpE?feature=shared

I hope it helps!

[booman809]

After much adjustments and tweaks I'm convinced this design won't work, likely too small of diameter of tube (1/2 PVC pipe) , or steel wool placement issues. Can someone remind where to place the steel wool in the tube? I thought it was a quarter of the length in but I'm at a loss.
Thanks

[Fool]

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Most of the Thermoacoustic Engine I've seen have a diaphragm and weight for a piston. The weight is adjusted for resonance. I don't know enough to suggest anything. Maybe where your Tee with the screw in plug us. The plug could be replaced by a diaphragm with a weight glued to it. To tune it, add weight in little increments, washers or coins, even different sized nuts?

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[tibsim2]

Hello! I mean you want to make a loop thermoacoustic machine. The machine won't work in this open state. If you want a branch, you put it on the other side, and the length of the branch is equal to a quarter of the loop. Since the loop is not very long, it will only work with a good quality core. Instead, I suggest that you get four test tubes and four mop tubes to be sure it will work. You don't need the branch as a first step. The machine works closed. Use four cores, and the loop should be 4 meters long. In this case, the machine will work with any quality core, but it will be stronger with rarer cores. The beginning of the video:
https://www.youtube.com/watch?v=5-r3HNbHEnQ&t=306s