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3D printed plastic burner experiments (photo heavy)


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On 1/7/2019 at 6:14 PM, Another FrankenBurner said:

I have been labeling the burner heads in 3 sections.  The accelerator block at the top, the ribs in between and the outlet below the ribs in the images.  The nomenclature could use some help.  The entrance to the "outlet" is an inlet.  I haven't put much thought into it.  The terms evolve as I gow.  For a while the ribs were labeled vanes.

I appreciate you being careful about proliferating terms. However, they are vanes; not merely ribs. I would call them vanes, if it was up to me :rolleyes:

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Vanes, NOT ribs. Ribs are not longitudinal elements, they are circumferential structural elements though not necessarily full circle. 

One of these days I must get a spinning lathe set up! I can't even experiment with what I think. <sigh>

Frosty The Lucky.

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6 hours ago, Another FrankenBurner said:

Uncle. Uncle. I yield. I shall refer to them as vanes going forward. :)

Here's the thing; when people just reach for the first handy term to attempt to describe burner or forge parts, without reading what others are using to describe those same parts, then a babel of confusion is generated.

When someone provides a NEEDED new term for a new part, with increased function, thoughtful people should go along with his or her new term; thus, consensus is generated.

When I started describing the struts that separated the air intakes in my burners as ribs, it was because it described their main function. When you deliberately changed the mere ribs in my burners to highly curved air foils in yours," ribs" simply ceased to be an adequate description for them.

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  • 1 month later...
On 2/14/2019 at 2:24 PM, Matt Watson said:

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.

I know this is quoting way back into this thread, but I'll let you know if this works because I accidentally did it to the little 1/4" burner I'm making when trying to thread the end to take the gas orifice assembly :lol::rolleyes:. The three-jaw chuck of the lathe clearly gripped the mixing tube better than the upwind end so when I applied pressure while trying to turn it, the tap gripped and it twisted at the supports between the air slots! 

My 3d printer extruder nozzles should arrive tomorrow so I'll hook it up and see if it will still function. Thankfully I've got plenty of this pipe left so I'll definitely be making a few of these with slightly different mix tube lengths and flame nozzle sizes/styles to better my understanding of the whole process. I'll be sure to make one "vanilla" version (without the accidental twist!) as a control to compare to.

Cheers,

Jono.

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Did the connecting ribs twist out or stay concentric?  Do you have a picture?

Another idea I entertained but never followed through was air inlets cut on the diagonal. I posted about it a few pages back.  I wanted to build the straight slot control burner and the diagonal version to see the differences. 

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Twisting the ribs between the air openings is one of the reasons I changed my design, post book, to three air openings, no matter how large the burner. I also found out that air openings, which are over wide can produce a ragged flame. As always, good performance comes from the right balance of all factors, rather than just "more, more, more."

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AFB, they stayed concentric (and nearly snapped!). They squashed right in tight and I had to untwist them. Think basket twist but they didn't bulge in the middle as they untwisted. I would have taken them back to straight but it looked like they would snap off.

I honestly don't know if it will make much difference but still I have to solder/braze a fitting on and take delivery of these 3d printer nozzles before I can test it.

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  • 4 months later...

I finally got around to learning enough to mess around a bit on FreeCAD.   After gleaning pertinent information and looking at the pics posted here I was able to create a reasonable facsimile of AFB's inducer.  AFB was kind enough to look over my file to see if there were any glaring errors as well.

I've been using NARBs for the past several years, and I like them a lot.  My idea was to marry the inducer with a a multiport burner.   So far I haven't done much testing, but I have found that a burner block that is about 3 inches deep with 180+ nozzlettes is extremely quiet, doesn't burn back into the plenum ever - even when shutting the fuel off- but unfortunately doesn't seem to reach the temps I'm looking for.  Just to be sure the burner block was the issue, I removed the inducer/mixing tube from the NARB and aimed it at a glowing forge interior. Wow!  The performance characteristics are amazing to me. It functions under 1 psi without burning back into the mixing tube and I was able to easily reach forge welding temps in a few minutes using less than 10 psi.  This was with a 3/4" mixing tube and a 0.30 mig tip - and my first attempt with no fine tuning and no flared nozzle on the end.

I still want to see if I can find a combination of this inducer and a multiport burner that function well together, so to that end I've designed a NARB body which should allow me to swap out burner face blocks so I can try different diameters, lengths, and numbers of holes using the same inducer, mixing tube, plenum, burner body, and forge.  Fortunately I can design and print plastic mold forms now. 

If I come up with anything that I think is worthwhile I'll probably post it over on one of the NARB threads.

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Well, yes, but within limits. More than a three to one constriction ratio between funnel entrance and the mixing tube's internal diameter is problematic. The limits also apply to shortening the conical air entrance. A sixty degree cone is a better shape than a forty-five degree cone. The shorter the cone the worse the problem.

So, why say probably? I have observed the problems that accumulate with forced-flow burners, but free-flow burners are more subtle; nevertheless, an obvious, repeatable, event in one type is likely to show up in some degree in the other type.

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I went with the ratios illustrated somewhere in this thread, and shown on the top right of the screen under posted images:  3 times the mixing tube diameter for the funnel entrance and twice the mixing tube diameter for the height of the funnel.  For the curve between the funnel opening and the the mixing tube I just played with it until it looked right to me.  I'd call it more of a trumpet shape.  I may not have all the dimensions optimal, but I was impressed with the unrefined results.

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