Optimum dimensions of a Rubens Tube?
There are several Instructables posted for Rubens Tubes, and I have seen a few elsewhere.
I'd like to make one myself, for demonstration purposes, but I'm wondering if there is an optimum set of dimensions?
I have seen diameters from about 2-10cm, and lengths from about 80cm to 2m.
And what diameter holes should I drill?
If it makes a difference, I'll be fuelling it with mains natural gas (methane) in a school lab.
(And, while I'm here, what would be a good rescued speaker to drive it? An old PC speaker?)
Discussions
Best Answer 8 years ago
What about push-pull speakers ? One at each end, in anti-phase.
The gas type affects the hole size, you have to make sure the burn velocity is comparable to the jet speed.
Steve
Answer 8 years ago
(Sorry Steve, hit Best instead of reply - that's the second time this week!)
I'm after minimum work and maintenance - it will probably end up spending 51 weeks of the year wedged in a cupboard. So, I plan to use a single speaker at one end, and a solid cap at the other (although I am also considering a rubber diaphragm so that children can shout at it and affect the flames...)
I don't know the pressure of the gas supply, but it doesn't burn back down a half-inch pipe, and makes a flame over a foot long when lit directly at the pipe (instead of at the Bunsen).
Answer 8 years ago
This is an interesting link, off the wikipedia entry.
http://www.fysikbasen.dk/English.php?page=Vis&id=6
Steve
Answer 8 years ago
So, looking at that, as long as you have a tube and holes, it will work...
(There are some other interesting demonstrations on that link)
Answer 8 years ago
You may have to play a bit with the gas pressure, but it looks like it.
Would be a neat thing for Halloween.....
Steve
Answer 8 years ago
Ha, I just had a mental image of a row of little pumpkin lanterns, all with flames coming out the top like candles.
Answer 8 years ago
What ? You too ?
8 years ago
Your school probably has a stereo set that will suffice, if you turn the volume up enough.
The rubber diaphragm (AKA deflated latex balloon) at one end is a great idea. Twelve years after the science lesson, I still remember being able to shout at those flames to make them dance!
That tube must've been about a meter and a half long, with centimeter-diameter holes. The smaller the holes, I'd imagine, the more sensitive they'll be to changing air pressure.
Answer 8 years ago
Thanks.