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.
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-
Last Edit: Nov 15, 2014 3:03:38 GMT -8 by PNW Dave
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 Presidents
Yes, 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.
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.
mercedes: Not sure where this question will end up...I just registered. HOW THICK SHOULD PERLITE/VERMICULATE/CLAY INSULATION BE BEHIND THE THERMAL BATTERY/COB BENCH IF IT BACKS UP TO A STRAW BALE WALL? Thanks! Can you please also post me: email@example.com thnx!!
May 28, 2018 20:05:23 GMT -8
kkp: Mercedes: Benches don't get real hot. In fact, they are rather cool compared to other areas. You shouldn't need a mix like you described
Jun 7, 2018 18:10:52 GMT -8
maartenmartens: beste Peter, ik heb je eergisteren een mail gestuurd via het contact formulier op je website , heb je die goed ontvangen ? mvg Maarten Martens, architect - geobioloog (mail betreffende de bouw van onze eigen RMH)
Jun 20, 2018 13:21:57 GMT -8
martinm: any one here with info \ experience with heat (from a mass heater) distribution with ducts throughout two storey house ?
Sept 8, 2018 22:58:52 GMT -8
padica: Good morning, this is a wonderful subject, please someone can help me with the theme of double and triple combustion, how it is achieved, theory and design, thank you
Sept 15, 2018 7:13:40 GMT -8
wiscojames: I'm afraid you won't get a response to such a vague question - I suggest reading through some of the threads related to your questions before asking for an explanation. People will be very generous with their knowledge if your question is more specific.
Sept 18, 2018 4:48:00 GMT -8
daniel: in my experience as I am working now on something of that nature, I have thought of making a heat exchanger and distributing the heat through vents using a slower fan. Now after a few years I realize that mass heaters give out primarily radiant heat, for
Nov 30, 2018 12:48:38 GMT -8
coastalrocketeer: Anyone posting in this shout box... if you have something you want people to see and respond to, create a thread in the appropriate forum section... this is not the place...
Dec 16, 2018 18:10:49 GMT -8
vesuvius: High Temperature Glass options,
Jan 4, 2019 16:28:17 GMT -8
vesuvius: Do any of you have experience with using the glass from home oven doors on a rocket stove? I'd like to have a viewing port on my stove but don't want to fork out for new ceramic glass. Any thought as to whether it would take the heat of a rocket stove?
Jan 4, 2019 16:30:40 GMT -8
yaya: you dont need the blowair for that temp..
Jan 13, 2019 16:43:57 GMT -8
flybywire: Glass window from an old washing machine is designed to take high temps. Cheap solution to your need.
Jan 27, 2019 0:10:58 GMT -8
coastalrocketeer: Anyone posting in this shout box... if you have something you want people to see and respond to, create a thread in the appropriate forum section... this is not the place to have a discussion... it is for short announcements
Feb 7, 2019 0:11:23 GMT -8
coastalrocketeer: you won’t likely get replies to questions here, and it is not a spot that makes holding an ongoing discussion possible...
Feb 7, 2019 0:12:22 GMT -8
TexasGonzo: Sooooo glad I found this site! Its always rewarding to find such a super group of folks! To any and all, feel free to PM me anytime. Thanks for having me!
Mar 11, 2019 18:56:41 GMT -8
jlmtech: GADGET: CONSIDER USING A JET PUMP INSTEAD OF A BLOWER FAN TO INDUCE DRAFT; NO CLOGGING.
Mar 26, 2019 8:19:28 GMT -8
michaelegan: i am unable to open the sketchup files on my mac. I used sketchup a few years back but apparently the company now requires a subscription. does anyone have any advice/instructions on how to use the program or how to view pictures without spending money?
Aug 20, 2019 18:41:48 GMT -8
mannytheseacow: michaelegan: download AutoCAD student version for free... import .SKP
Aug 23, 2019 13:33:44 GMT -8