Another FrankenBurner

3D printed plastic burner experiments (photo heavy)

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13 hours ago, Another FrankenBurner said:

As is, with the 1/2" burner, I am anxiously awaiting the mig tips.

Can't you print jets? They aren't in a HOT zone if you mount the burners horizontally or vertically up. I'm thinking 0.0175" would be a good departure point for a 3/8" burner. 

Increasing induction is a good darned reason to taper the mixing tube to the nozzle you know. You'd be able to feed it more fuel and it'd inhale enough while the taper slowed the mix so it didn't just blow through the forge. 

Hmmmmm?

Frosty The Lucky.

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I could try to print jets.  My print quality would leave a bore which causes turbulence.  I might be able to print small and use letter bits to open it up.  Fun idea.  

A burner head with a taper after the throat lengthens the head which I imagine decreases the required diameter so it is a trade off.  The big challenge I have been up against is that it also means the mix tube length is shorter which is no good when the head is plastic.  

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You will probably end up needing a .020" to .022" jet orifice size, although his burners might even draw enough air to support an .025" orifice. I ended up with slightly longer than 1/2" lengths of heavy wall capillary tube trapped in MIG tips with interference fits, on my own 3/8"  burners.

With such small orifice sizes, friction increases with tube length much faster than in MIG tip orifices. As a result of high friction resistance, tube length becomes a better method of fine tuning jet performances than than exact orifice diameter. I ended up settling on heavy wall stainless steel "gauge" tubes, which only come in sizes like. .005", .010", .015", >020", etc. I cut my tubes 5/8" long, pushed them into position. and then hand sanded them back with very fine sandpaper, until the burners ran correctly.

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2 hours ago, Another FrankenBurner said:

I suspect that increasing the diameter increases both, spin and air induction.

The greater the ratio between air entrance diameter and mixing tube diameter the stronger the vortical flow is. Vortical flow is much subtler than simple air induction.

How much air is induced is mainly a question of jet orifice diameter to mixing tube diameter. Induction is also effected by mixing tube length, which substracts from the amount of induction the longer the mixing tube is, by friction. Induction is also effected by the diameter of the flame retention nozzle, which adds induction to a smaller amount than mixing tube friction subtracts from it.

Clear as mud?

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So, you might need to drill jets, be careful friction doesn't melt the plastic to the drill bit.

You could easily print the correct gauge tube into the unit. Easy peasy.

I was jonesing for full length taper mixing tubes like the old days. Printing one from plastic is a nonstarter for the REALLY obvious.

Mike: The stronger the vortex the stronger the vacuum in the center. Doesn't that mean a stronger vortex means greater induction? Induction is about pressure differential or do I have it wrong?

Frosty The Lucky. 

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5 hours ago, Mikey98118 said:

How much air is induced is mainly a question of jet orifice diameter to mixing tube diameter. Induction is also effected by mixing tube length, which substracts from the amount of induction the longer the mixing tube is, by friction. Induction is also effected by the diameter of the flame retention nozzle, which adds induction to a smaller amount than mixing tube friction subtracts from it.

I think I am misunderstanding, are you saying that the main factor to amount of air volume induced is the jet orifice diameter to mix tube diameter ratio?  

With the same mix tube and jet diameter I have printed inducers which vary the air induction widely, depending on their design, so I am confused as well.  

I induced smoke into a few of the versions.  It induced straight in until it entered the fast moving cyclone inside the inducer.  The closer to the throat, the tighter and faster the cyclone.   Now I just need Frosty's smoke pressurizer.  I also want to play with the aquarium and food coloring.  Fun to actually see something instead of imagine it.

I also played with the 3/8 burner some more.  I am able to induce enough air to have a neutral flame at 5 psi.  It's btu minimum is higher then the 1/2 inch.  I have a piece of fire suppressant pipe which is also 3/8 pipe but the ID is larger.  It runs neutral at 3 psi.  Amazing how small of changes in dimension make such big changes in flame.

1 hour ago, Frosty said:

I was jonesing for full length taper mixing tubes like the old days.

I am trying to figure that one out as well.  

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The smoke gun was based on the ones used by bee keepers and frankly what worked best escapes me right now. It was basically a closed container with a tube outlet. Put straw, saw dust, etc. in the chamber with a burning coal and feed air in. The fresh air keeps it smoldering and forces smoke out the spout. I messed with a couple versions till I got one that worked. Later I realized a 4th of July smoke bomb pellet would've worked a treat but maybe made too much. A cigarette wasn't quite right, too hard to aim.

I think Mike's referring to the balance a burner needs to strike between induction forces and the losses caused by skin friction in the tube. I don't think it's something to worry about at this stage, what you're experimenting with is intake shape and it's effects.

I tossed out tapering the whole mixing tube more for conversation's sake than as a serious suggestion. It is the old school way to handle both factors at the same time though. The expanding cone greatly reduces skin friction while lowering pressure which increases induction force. It's just not something to mess with right now, it's a wheel that's been invented and developed long back. 

Changing more than one thing at a time will only confuse what changed what. 

Frosty The Lucky.

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Mikey: I reread principles material on vortex burners and think maybe I am understanding a little better.  The intent is to create a fast moving vortex so that more air can be induced without providing additional push/pressure.  Instead of focusing on how much air I can induce, I should be focusing on creating as strong a vortex as possible, as it will induce all the air needed along with a host of other benefits.  Do I have that right?  

In the latest burners 101 post about burner dynamics, you mention both spin and vortical flow, could you elaborate on the difference?  I am thinking spin is air spinning down the outside of the mix tube where as vortical flow is a fast moving cyclone down the center of the mix tube.  Do I understand that correctly?

If so, is there anything I should change to attempt more votical flow?

Frosty: I was just thinking of how to make a tapered tube.  I will not change more then one thing at a time.  I am confused enough without making it worse.  Especially when Mikey comes in with a mental curve ball. 

For smoke, I rolled a piece of paper towel tightly and let it flame until an ember.  I created a small ember to see a small piece of the stream and a long one to see it flow around the ribs and such.  I learned a bit about what is going on in there.  I have some video's but I have to see if any are good.  Between lighting, holding the camera, holding the smoke, and remembering there was a hot flame at the one end, I suspect the video's are fairly poor.  If so, I may try to pull out a few stills.  

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On 2/10/2019 at 4:47 PM, Frosty said:

Mike: The stronger the vortex the stronger the vacuum in the center. Doesn't that mean a stronger vortex means greater induction? Induction is about pressure differential or do I have it wrong? 

Yes, it does, but not induction generated at the mixing tube entrance. Air induction from vortex action will happen at the mixing tube outlet; in other words induction from a burner's vortex action comes about just behind the flame, and it comes by strengthening the partial vacuum created in a flame retention nozzle (or by increasing the difference between mixing tube pressure and forge atmosphere pressure, at the flame interface at the end of a bare mixing tube). This difference only effects flame retention nozzle design; not overall air induction, as such. So, most builders would find this to be a distinction without a difference; but designers need to know that difference :)

In a classic venturi burner it should require changes in taper angles, for instance.

It, might lead to a taper/stepped nozzle becoming superior to either tanered or stepped nozzles; who knows?

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Putting a flare on the mixing tube is the result of a misunderstanding on Ron's part about tapered mixing tubes. I started to correct the mistake but he'd included a pic of the flame and I had to admit it REALLY improved his. 

That it also held the flame on or near the nozzle is serendipity. The tapered nozzles aren't retention devices unless you're pushing way too fast a mix down the burner to keep it lit, making it a bandaid. 

Frosty The Lucky.

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6 hours ago, Frosty said:

That it also held the flame on or near the nozzle is serendipity. The tapered nozzles aren't retention devices unless you're pushing way too fast a mix down the burner to keep it lit, making it a bandaid.

I used flares from the first because I found them necessary; remember that I always considered the burners role as air/fuel hand torches, rather than just as burners within heating equipment. It did not take very long to find his tapered flame nozzles insufficient for my needs :)

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And I just break out my oxy propane rig when I need a torch of any normal type.  Another reason so many people have trouble getting hand torches to work in bean can forges, they just aren't intended for the environment.

I'm not arguing flares work or not, they're just not really "flame holders," though they do that too. If you use one just for holding the flame and it works. It's a good mod.

Frosty The Lucky.

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I was under the impression that flame holding was the original reason that flared nozzles were added to homebrew burners.  Ron described making solid fuel fires inside a forge, which used aussie burners, until the forge got to autoignition temperatures, so the flame would not be blown out.

Isn't having an increase in volume after a straight mix tube important?  Whether that be a forge or nozzle of some sort.  

I am able to maintain a clean flame out the mix tube sans nozzle but it's btu output is low and the mix tube velocity is critical.  Too high and I get blow off, too low and I get suck back.  This range is pretty small.  If I want for higher output, I have to move more volume.  The only ways I can think of doing that are higher velocities, larger geometries or a combination of both in the case of a nozzle.  

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We are on the verge of falling into an "apples and oranges" misunderstanding. Ron is speaking about what is necessary to maintain a burner flame within a forge. You and I look on burners in themselves; with or without a forge. Both viewpoints are right and necessary. Thre is no argument, unless we cause one...

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On 1/8/2019 at 7:04 AM, Mikey98118 said:

I have been looking for a way to invite the interest of home casters; they have a lot to teach blacksmiths about some of these subjects; not to mention that 3D modeling is the perfect tool for helping to manufacture up to date equipment. I hope John in Olympia will jump into this discussion with both feet :D 

I THINK IT'S TIME FOR ANOTHER PERMANENT THREAD!!!

It looks like you have settled the question of whether or not spiraling air opening are worthwhile; they are :)

After looking at this design and since I've been looking at yours as well and have a little experience with blacksmithing now I am wondering if you were to heat your air opening up and twisted it wouldn't it create this same effect and cut the need to cast it? I'm just guessing here but that what I'm seeing when I look as this is the slotted material left would turn and it should create a twist in them essentially making them into blades. The only issue I can think of with doing that would be keeping it perfectly aligned centered with the opposite end.

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1 hour ago, Mikey98118 said:

Thre is no argument, unless we cause one...

My intention was not to argue.  I am not the arguing type.  If a discussion has devolved into an argument, it is no longer constructive.  When I do question or disagree with a statement, my reasoning for discussing is to educate myself.  I have no convictions in any of this.  I'm just the curious type and question everything, trying to get to the whys of things.  

 

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2 hours ago, Matt Watson said:

I am wondering if you were to heat your air opening up and twisted it wouldn't it create this same effect and cut the need to cast it?

Not even close. I am all in favor of home builders being able to do everything possible by themselves, but trying to turn a sow's ear into a silk purse is taking a step too far :P

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3 hours ago, Matt Watson said:

I'm just guessing here but that what I'm seeing when I look as this is the slotted material left would turn and it should create a twist in them essentially making them into blades.

No, the 3D printed / cast blades are air foils, not flat paddles. Big difference. It's an idea worth a little thought though. Don't stop.

Frosty The Lucky.

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Matt,

It takes four cuts to make a rectangular opening in a burner tube, but those cuts don't have to form a rectangle; they could be made into a parallelogram almost as easily. Furthermore, if only the forward and aft cuts, (across the tube's axis) and the forward (longitudinal) edge of the   parallelogram remained in place, while the back longitudinal was joined by a third bend line (parallel to the axis) before cutting, and then the forward crosswise line was extended to reach the cut line, then, after cutting, and bending three such equidistant air opengs, while not for getting proper beveling of all cut surfaces...this would be as close to Another Frankenburne's air chamber as you're going to get on a tube burner, The same treatment could by made to the air chamber on a Hybrid type burner.

BUT, that's a wholl lot of work to do on a gamble :)

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Ok, I do not have the intelligence yall have. Frosty you stated the paddles aren't flat and while my initial comment was to simply twist the air opening on the Mikey burner to achieve this I believe a little tweaking with scrolling pliers would be needed to  get the right pitch of the blades. Also in order to get the blades to create the desired effect they would have to be on the inside diameter of the pipe I think is what you were saying Mikey. I read your comment several times and still couldn't fully understand it. could you have a smaller diameter pipe section (use a spring fuller to radius the section that you want the blades in prior to cutting) then cut the equal blade section out and twist / bend into the desired blade pitch. I state pitch since that is the term used for boat propellers. Also you could use 4 instead of three if thinking along the idea of a propeller. Although I am probably again just making things too complicated and in the end may not work.

I looked at an older propane burner that just screws onto a 1lb bottle last night. It had a larger diameter flame retention nozzle than the new ones that are the same diameter as the mixing tube and you could unscrew it and separate the mixing tube and flame retention nozzle at the orifice which seemed to be a solid brass pipe. I did this while it was lit and started to see how far away from the orifice I could get it before it extinguished. I was able to get about an extra inch away from it before the flame went out. But while I got to looking at it and a new one that I have I noticed they are both the same except for the diameter of the flame retention nozzle. Both were roughly 3/8'' pipe from orifice to end and the orifice was I'm guessing but probably .010''.  The older one had a 1/2'' flare retention nozzle over the mixing tube but instead of fitting flush against the other pipe it had tack welded spots or little cut outs around basically a washer with a 1/8'' center hole. The newer one has a recessed smaller washer with about a 1/8'' center hole and instead of the cutouts like the other one it looked like a crimped piece of sheet metal all the way around it in like a star pattern. Can either of yall explain to me how these work compared to the designs such as yours? 

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There are several ways that work to make incoming air swirl:

The most common way is to stick a reducer fitting on the air entrance of your burner. Any kind of funnel shap will cuase air passing through it to form a vortex. vortical flow produces far more benifit than merely swirl the incoming air. Nevertheless, their are ways to increase vortical flow, from the right kind of fan blade, to using blade shaped ribs to hold the gas tube and and its jet in place at the burner opening. Hybridburners.com have air chambers on the large opening of their burner's reducer fitting, with three air slots in them to do the same job.

Jet-ejector burners have one or more side air entrances to create swirl. On a tube design like a Mikey burner, the entrances are cut into an air chamber section  that dumps the air induced from the gas stream into the mixing chamber; in these burners the air is swirled by being forced to make a change of angle as it enters the tube, but there is no vortex action going on. In a "T" burner the swirling action happens from two air streams from two pipe openings meeting at the fittings center, before funneling down a smaller opening that the exit into the mixing tube through; that smaller opening is smaller, and therefore creates vortical flow in the swirling air. So, vortical flow; not just air swirl is the secret behind the "T" burner's excellence. There are burners being marketed that are basically a gas drilled a drilled and capped gas tube welded across the end of a mixing tube. As the drilled hole in the side of the gas pipe induces air between the wall of the gas pipe's sides and the remaining opening of the mixing tube, it is forced to swirl; thus, this dimple burner works surprisingly well. Whether such a tortured shape ss these two air paths can also create a vortex is past my understanding.

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Thanks for the clarification Mikey.  I have been studying vortices lately.  I also borrowed my grandfather's copy of Basic Science for Aerospace Vehicles by Northrop Institute of Technology and have been reading about airfoils, turbulent and laminar flows, drag, boundary layers, skin friction, etc.  I have a handful of idea's to play with.  My latest experiments have all been geared towards a more powerful vortex.

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Yes, I noticed. You have combined the best features of Hybrid burners and Mikey burners, and added a nice little twist of your own :)

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Thank you Mikey for simplifying that I understood it a little better.  I like it when yall add specific scientific terms in these post so I can look them up and learn some more. I'm starting to enjoy the science behind the burners and forges / and also building them just as much as I enjoy actually forging. If I could just get my son to sit down and learn it with me that would be an amazing accomplishment for him. He stays with me for a few minutes then gets bored with it and would rather just burn something. Guess I cant blame him since he's ten and has ADD just like me. 

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