|
|
Post by PNW Dave on Nov 15, 2014 0:36:09 GMT -8
I found these old videos on youtube and started putting together a playlist " Flow Visualization". The concepts of laminar flow, flow stall, reverse flow, pressure vs velocity etc. are demonstrated. While this is done in a liquid medium and we are generally interested in gas, the concepts are presented clearly. I enjoyed watching these so much, I just had to share. I'll embed one for your viewing pleasure. |
|
|
|
Post by satamax on Nov 15, 2014 2:35:23 GMT -8
|
|
|
|
Post by PNW Dave on Nov 15, 2014 2:38:50 GMT -8
The segment below immediately made me think of the P-Channel, and so potentially adding to the theory of why it works. Where gas of higher density is added into the flow at the top of a lower density gas.
Fresh air entering the burn tunnel through the P-Channel is presumably cooler than the air (flames) already in the burn tunnel. This causes instability which provides for turbulent mixing, as shown below. Although, in our situation we may want the air to be preheated in order to prevent excessive cooling of the burn and aid in efficient combustion, it won't ever be preheated to equal temperature as the combustion itself. Thus the effect still has potential, in theory. Whether or not this actually has a significant effect, I don't know.
I figure this concept in combination with Peter's idea of the volatile gasses tending to flow at the top of the burn tunnel makes for efficient mixing and a nice clean burn.
I've embedded the video set to start at 23:05, where the example I reference is demonstrated-
|
|
|
|
Post by satamax on Nov 15, 2014 2:46:14 GMT -8
Dave, i think the best visualization for the P channel would be one of a pitot tube! That post would earn you apples at permies  ! |
|
|
|
Post by PNW Dave on Nov 15, 2014 3:01:09 GMT -8
For fuck sake mate! Whay haven't you dug that before! Well, the sound seems to be a little wonky! Thanks a lot anyway! HA! I've only recently found these myself!  But physics and conceptual understanding is one of my favorite late night pastimes. For anyone with similar interest, I highly recommend Richard A. Muller's course "Physics for Future Presidents" from Berkley, CA. (though not rocket stove related at all). All lectures from the course are available to view for free. I've seen every one since the 2006 semester at LEAST once, so long as it is Muller or Bob Jacobsen... I didn't care for the more recent lecturers. Here is a playlist on YouTube- Physics for Future PresidentsYes, who ever did the video conversions did not compensate for differing video and audio rates, so the video progressively lags more and more behind the audio. In some places you'll hear the narrator describe something that won't be on screen for a few seconds. So it is good to keep that in mind while watching. |
|
|
|
Post by Daryl on Nov 15, 2014 4:48:23 GMT -8
Awesome thread, Dave. For those wanting to get even more lost (in a good way), google Thermodynamics. Another topic to google, Bernoulli's Principle.
|
|
|
|
Post by satamax on Jul 20, 2015 4:07:28 GMT -8
So, two new ones i discovered today!
The first is rather close, i think, to what is happening in the port of a batch box and behind.
The second one looks prety much like what should happen behind Matthewwalker's pre port secondary air!
HTH
Max.
|
|
|
|
Post by satamax on Jul 19, 2018 5:00:59 GMT -8
Thought these should be added here.
Thanks to SteveStuff.
|
|
|
|
Post by satamax on Nov 18, 2018 7:33:24 GMT -8
Getting grumpy with people who don't understand fluid mechanics. I had to research few other videos, here they are.
Despite the funnel end, this can well illustrate what the exhaust of the heat riser does.
This one is even better,
If you immagine what happens in, a T, the two blue regions are increased, even more turbulent, and the gases crashing on a flat surface instead of a sharp point, create even more turbulence. Mixing with the stalling blue adds more and more drag on the gases.
|
|
|
|
Post by Orange on Dec 4, 2018 11:14:45 GMT -8
|
|
|
|
Post by satamax on Oct 1, 2019 10:08:50 GMT -8
Guys, did anybody save those disappeared videos? I went to the wayback machine, none of the videos were saved. These were posted by VerraStrngNUCF There is a link where a whole set of flow visualisation video is. web.mit.edu/hml/ncfmf.html |
|
|
|
Post by satamax on Oct 20, 2020 4:04:28 GMT -8
|
|
|
|
Post by satamax on Jul 2, 2021 2:13:25 GMT -8
Guys, something cool looking .
12.50 and 20.30, check for the vortices!
|
|
|
|
Post by Vortex on Jul 2, 2021 4:55:50 GMT -8
|
|
But physics and conceptual understanding is one of my favorite late night pastimes. For anyone with similar interest, I highly recommend Richard A. Muller's course "Physics for Future Presidents" from Berkley, CA. (though not rocket stove related at all). All lectures from the course are available to view for free. I've seen every one since the 2006 semester at LEAST once, so long as it is Muller or Bob Jacobsen... I didn't care for the more recent lecturers. Here is a playlist on YouTube- 
