A narration of this (including the other vid), how it works, why it works and, maybe, how to make one. If I recall properly, this technology, or some variation of it, is making its way into refrigeration. Thanks for sharing.
Milan: The two frequencies you hear are because there is another engine in the same assembly that starts up just after the one I'm filming here. The third engine is covered and so it doesn't run. See "Triple Solar Thermoacoustic Engine" to see the whole thing. The length of the tube is 26 cm.
It should certainly be possible to build a refrigerator but I simply have not tried it yet.
@blackcreekresearch Uh, I calculated frequency for open/open resonator cavity (for Rijke tube, f=nV/2L) instead close/open (for Sondhauss, f=nV/4L). So, at average temperature of the cavity of 63.26°C speed of sound is (on average as well) 369.2 m/s if your cavity is 0.26 m long.
It is also interesting that I see second and third harmonic, while no other harmonics. And amplitude of both high harmonics are about the same, so that might be reason of canceling out other harmonics.
Measured two frequencies - one 300 Hz, and another about 355 Hz. If temperature difference is over 100°C (if ambient is 25°C, then hot spot is about 125°C), then this may explain two frequencies due to two different speeds of sound inside resonant cavity.
If I am correct, and your tube is 50 cm long (total, including prime mover), then acoustic refrigerator is (almost) easy to build. Got "Eureka moment", so please help. :-)
Very nicely made. Have you tried putting an audio speaker at the output and seeing how much power it can generate? I'm thinking of placing an array of these along the exaust stack of my outdoor boiler. I assume proportions of the resonance chamber are critical. Did you find them somewhere or derive them yourself?
@Nanopaulg: Google "Thermoacoustic engine" for a complete description. Watch out for "laminar flow stirling engines", which are pretty cool but are sometimes mistakenly called thermoacoustic engines. Briefly, this acts like an organ pipe, but it is not driven by external air pressure. There's a region inside filled with small capillaries that allow the air to alternately take up and release heat to the walls very quickly until the heat reaches an exchanger that releases it outside.
I have no way of measuring acoustic power, but the efficiency must be in the ballpark of single-digits. However, this is far from an optimized design! The main problem is tha tit uses atmospheric-pressure air as the working fluid. Engines designed to provide useful power use about ten bar helium as the working fluid, which greatly raises the efficiency. Google "Thermoacoustic Engine" to find some good sites where real research is going on. Los Alamos and U Penn are both working on this.
@blackcreekresearch did u put some wool inside and the inbetween of the pipe, i made a copper pipe do that once with some metal wool inside, it was not as loud as that though, great work!
A narration of this (including the other vid), how it works, why it works and, maybe, how to make one. If I recall properly, this technology, or some variation of it, is making its way into refrigeration. Thanks for sharing.
darthom 2 weeks ago
Milan: The two frequencies you hear are because there is another engine in the same assembly that starts up just after the one I'm filming here. The third engine is covered and so it doesn't run. See "Triple Solar Thermoacoustic Engine" to see the whole thing. The length of the tube is 26 cm.
It should certainly be possible to build a refrigerator but I simply have not tried it yet.
blackcreekresearch 6 months ago
@blackcreekresearch Uh, I calculated frequency for open/open resonator cavity (for Rijke tube, f=nV/2L) instead close/open (for Sondhauss, f=nV/4L). So, at average temperature of the cavity of 63.26°C speed of sound is (on average as well) 369.2 m/s if your cavity is 0.26 m long.
It is also interesting that I see second and third harmonic, while no other harmonics. And amplitude of both high harmonics are about the same, so that might be reason of canceling out other harmonics.
MilanKarakas 6 months ago
Can you tell me length of the tube?
Measured two frequencies - one 300 Hz, and another about 355 Hz. If temperature difference is over 100°C (if ambient is 25°C, then hot spot is about 125°C), then this may explain two frequencies due to two different speeds of sound inside resonant cavity.
If I am correct, and your tube is 50 cm long (total, including prime mover), then acoustic refrigerator is (almost) easy to build. Got "Eureka moment", so please help. :-)
MilanKarakas 6 months ago
that made my screen resonate!
khoham 6 months ago
And sound will not traverse a vaccum, but sure beats wind chimes nice tone,put a speaker on it and use the vib coil to generate a/c
advthinker 9 months ago in playlist biochar carbon sequestration syngas
where can I purchase one of these or learn how to build one? verys interested, thanks
doxprodigy 11 months ago
I'd set these in my backyard XD
xXfreakbotXx 1 year ago
Very nicely made. Have you tried putting an audio speaker at the output and seeing how much power it can generate? I'm thinking of placing an array of these along the exaust stack of my outdoor boiler. I assume proportions of the resonance chamber are critical. Did you find them somewhere or derive them yourself?
MichiganMaker 1 year ago
@Nanopaulg: Google "Thermoacoustic engine" for a complete description. Watch out for "laminar flow stirling engines", which are pretty cool but are sometimes mistakenly called thermoacoustic engines. Briefly, this acts like an organ pipe, but it is not driven by external air pressure. There's a region inside filled with small capillaries that allow the air to alternately take up and release heat to the walls very quickly until the heat reaches an exchanger that releases it outside.
blackcreekresearch 1 year ago
This is interesting, how precisely does it work?
Nanopaulg 1 year ago
@boxa888: You can make a pipe oscillate with a metal screen in the end heated with a torch, but this is a little different. Thanks for the comment.
blackcreekresearch 1 year ago
interesting idea, Im now going to go away and pump my lamina flow engine full of helium and retest its rpm , Thanks for the idea
mimic58 1 year ago
I have no way of measuring acoustic power, but the efficiency must be in the ballpark of single-digits. However, this is far from an optimized design! The main problem is tha tit uses atmospheric-pressure air as the working fluid. Engines designed to provide useful power use about ten bar helium as the working fluid, which greatly raises the efficiency. Google "Thermoacoustic Engine" to find some good sites where real research is going on. Los Alamos and U Penn are both working on this.
blackcreekresearch 2 years ago
@blackcreekresearch did u put some wool inside and the inbetween of the pipe, i made a copper pipe do that once with some metal wool inside, it was not as loud as that though, great work!
boxa888 1 year ago
thats awsome!!
I want toknow the efficiency of the this engine. or atleast output power!
plz respond!
hottermale 2 years ago
very coolllllllllll
SWINGREGORY 2 years ago