3D printed plastic burner experiments (photo heavy)

[D.Rotblatt]

9 hours ago, Frosty said:

I'm wondering if fluting the OD of the jet holder in your second series of pics might improve or inhibit vortex.

I have some versions of that.  I'll print one up and see.  Might just disrupt the flow though...I'll give it a try.

30 minutes ago, Another FrankenBurner said:

Do the flames look the same to the eye as they do in the pictures?  

Pretty much, they have a slight dark or hollow center and the flames are very feathery on the edges.

 

30 minutes ago, Another FrankenBurner said:

Are you meaning the spiral ridges in the reducer or the shape of the reducer itself?

The spiral ridges in the reducer.  It is definitely better then a pipe reducer.  Besides, as soon as I get into putting in fins/spirals inside the burner, it becomes difficult to create a core to sandcast the pieces.  

30 minutes ago, Another FrankenBurner said:

I tried some similar experiments I called version 3.2

Thanks!  I'll look back and see what you did.  I've read the thread, but don't remember all the different iterations.

OK...I looked back at the beginning of this post and all I can say is: D&*^n you FrankenBurner....now I'll have to reread the whole thread.  You're experiments are detailed and done very well!  Thanks for all the work!

DanR

[Another FrankenBurner]

You are welcome sir.  If you think this thread is long, I have kept a journal with scribbles, doodles, equations, and mad ramblings through the process.  

As to the version 3's where I did similar wasp waist experiments with the expansion after the throat, I did see some interesting/radical performance.  I ended up going a different direction along my travels but I have not followed that design style far enough.  

[D.Rotblatt]

2 hours ago, Another FrankenBurner said:

I ended up going a different direction along my travels but I have not followed that design style far enough.  

I'd been following the thread, but totally forgot the wasp shaped burners you made.  It's amazing that the one I made is almost identical to yours.  I was looking at the Amal burner and riffing off that...form follows function I guess. I think it may be an interesting direction.

After rereading some of this thread I'm now printing out some more wasp necked with larger funnel in three lengths.  Also some funnels alone without the wasp neck...we'll see the differences.  I also am doing a mid length wasp with a spiral "fins"? like your final design to see if it makes a difference.  The longer wasps neck down smaller then the 3/4" tube then have a 1:12 expansion to the size of the ID of 3/4 pipe.   

My parameters are a little different: 1) 3/4" burners rather then 1/2", 2) something I'll be able to sandcast without much difficulty, 3) they work better then the riel burners or the mickey ones I have.  4) will make a good injector for my NARB - it's set up to take any 3/4" burner as the injector.  5) I want to be able to choke it down so I can get a reducing flame for forge welding, or slightly reducing for regular forging.

Thanks again for your fine scientific method and work! (I used to teach MS Science...love good scientific method!)

Dan R

[Another FrankenBurner]

No problem on the work.  I learned a lot on this forum and wanted to share.  

I look forward to your experiments and results.  I think the wasp waist(venturi) is superior but I could never get it to play well with pipe after it.  With your 3/4 pipe, if you stick to standard ratios, the throat will neck down to around 1/2 inch.  The long slow 1:12 taper will be the mix tube.  This makes the 3/4 pipe a supply line more than part of the inspirator which you just choked down.  If you have a throat that matches 3/4 pipe ID and taper up from there, you end up with an outlet around 1 3/8 which makes the burner quite larger then a 3/4 pipe burner.  If you cast this larger burner, you probably still need a section of pipe to distance the cast from the heat of the forge.  Maybe not with a NARB.  

Maybe in the partial venturi ratios there is a balance point which performs better then a reducer alone.  I didn't tinker enough to know much of anything here.

I followed any direction that induced as much air as I could.  This was so that I could push more btu/hr out of the pipe.  This inevitably cranked the velocity flowing down the mix tube which requires larger nozzles to put on the brakes.  It is still smaller and outperforms the 3/4 burner I used to use.  I am happy with it's performance and my fuel savings.  I would like to see what it would do with the proper outlet taper.

 

[Frosty]

8 minutes ago, Another FrankenBurner said:

I would like to see what it would do with

Funny how so many advancements start out with someone saying, "I wonder what'll happen if . . . "

If you're going to taper a full 8x mixing tube the output should be slow enough it'll work a treat in a multi outlet burner. Remember they like a trumpet bell intake too. 

Frosty The Lucky.

[Another FrankenBurner]

I have recently been doing a lot of quick and dirty experiments to increase my understanding of things:

[Frosty]

Is that sort of a home made manometer? Cool test indicator, I can't see water in the tube in the epic, a little food coloring fixes that. The lowest pressure should be at the throat, narrowest place. What did the burner nozzle indicate pressure wise?

What a great idea, wish I'd thought of that.

Frosty The Lucky.

[Another FrankenBurner]

Manometer, what's that?  This is just some aquarium tubing and water.  

Or as my coworker always says whenever anyone says manometer, "How do you measure a man?"

I would use the food coloring but whenever I do, I always get caught red handed.

The pressure is lowest at the throat, yes.  Below ambient pressure.  The pressure at the beginning of the converging section(inlet) is near ambient, it drops in the throat and it mostly recovers by the end of the diverging section.  When measuring the difference between the inlet and the outlet, the inlet is just a bit higher than the outlet.  The diverging section on this print had a length of 8x the throat diameter.  

By varying the position of the jet, I can tweak the throat pressure.  I have a few more quick experiment ideas before I tinker with inducers some more.  

[Frosty]

Yeah, I guess it's more of an un-metered gauge than a meter itself. 

When I use food coloring I get out a syringe to keep my hide as far away as possible. A tiny styrofoam bead or chip on each end of the water makes a good marker.  

None of the gas company guys using a manometer has laughed when I asked them that, most don't react at all. Think they've heard it before?

That's about what I expect pressure differentials to be in the burner structure. I'd sure like to see a more exaggerated intake wider but not much deeper. The trick is getting an efficient curve to encourage lower psi on the surface. The wider the bell the more angular momentum is conserved and greater the vortex. 

The problem is it'll probably require a choke plate so the intake air must start at the outside edge of the intake flare

I can't help thinking about this stuff. Math just looks like the beginning of a scrabble game to me though. I only know who Bernoulli was, not how to use any of his hard work. <sigh>

Frosty The Lucky. 

[Another FrankenBurner]

I was kidding about it not being a manometer.  It is the original.  I could easily get out a ruler and measure pressure in inches of water column.  Not that I did.  Makes a handy level as well.

I too want to know more about the inlet curve.  I have tried several wider and shorter curves but they weren't as successful.  I know nothing on the science behind the best curve.  I can't seem to find much information on the subject.  If you have any information on the subject or even have a guess at what might work, I am interested.

I am pretty sure we want more power to the vortex for his lower internal pressures and mixing but I haven't quite figured him out.  All I know is that the current versions produce 3 vortices which feed into the main vortex in the throat and when that started, I had to jump in orifice size.

While I enjoy math, there is not a lot of calculating going on over here for this.  Definitely no Bernoulli calculations.  Mostly a lot of observation, head scratching, research, new idea and repeat.  Sometimes I stumble into better understanding, other times into deeper confusion.  

[jwmelvin]

AFB, thanks for continuing your work and posting about it. Seeing the venturi tube made me think. I'm still not clear as to the role of the throat, in that it accelerates the flow but then expands the flow right after that; such an action will lose energy compared to just flowing through a fixed diameter, so there must be a point. Perhaps the reduced pressure at the throat is what induces more air flow from the ambient pressure around the entrance. Or maybe there is something about a reduced diameter that allows the gas jet to impart more momentum to the induced air flow. Anyhow, I did a bit of reading and came across this study, which seems pretty relevant to our purposes. Have you seen it? One point I found interesting is that the optimum inducer nozzle design depends on the configuration of outlet ports (i.e., the back pressure created by an array of outlets, which we call a ribbon burner). So I will probably work on inducer design more now that I have settled on an outlet block that I like. 

[Frosty]

AFB: I just THOUGHT it was sort of a manometer but don't you have to measure water column against a vacuum or is that mercury? 

From what the old commercial linear inducers looked like. The intake trumpet bell was air foil shaped and usually several times as wide as the throat but the choke plate caused all the intake air to enter on the rim of the flare. I never noticed any vortex in the flame however every application I've seen turns corners and or feeds a multi outlet burner. The asphalt hot pan on the patch truck had two pipe with outlets ribbon burners under the pan driven by a single linear inducer. I never took it apart to measure and there were no specs on the ID plate but it wasn't very big.

JW: The throat accelerates the fuel air mix driven by the primary. (jet output) Accelerating through the throat lowers pressure in the stream and behind it. Largely due to boundary effect lowering pressure against the curved surface of the throat itself. It only appears to be MAKING energy, it's really lowering entropic effects be eliminating friction almost completely. Bernoulli's observation and calculations showing that any fluid flowing over a curve creates a boundary of low pressure in contact with the curved surface and so moves more easily, eg. FASTER. A curved surface is a curved surface inside the curve, outside, along it or across it, it causes a boundary effect. This happens full length of a burner. The intake ports on the T burner may not.

The flow then expands in the mixing tube after the throat but is slowed down because it has to expand to take up more volume. The same quantity of gas filling a larger volume must be at a lower pressure, twice the volume, half the pressure. Yes? It's still moving though so it MUST lose velocity, it's converting a % of flow and energy sideways to fill the wider tube. Yes? All this adds up to better induction.

I can't do the math but understood what Bernoulli was talking about and got a decent handle on what was going on. But NO I still don't know why a jet ejector type inducer is more efficient than a linear. He explained that almost entirely with math.

Frosty The Lucky.

[Another FrankenBurner]

JW: I was writing my response and Frosty posted.  I will still post my response even though it says similar.

No problem on the work, I enjoy it so it doesn't seem like work.  Thank you for sharing your work as well, same for Dan and anyone else sharing their knowledge.  You never know where inspiration will come from.  My playing with the standard venturi again was a direct result of Dan playing with something similar in his experiments. 

You are correct about the venturi losing some energy but a better way to think about it is the venturi is using that energy.  The potential energy of the fuel pressure in the cylinder is converted to kinetic energy at the orifice.  This kinetic energy is the motor.  The only purpose of the motor is to draw in air, mix it with the fuel and deliver it.  I think the purpose of the converging inlet is both of the reasons you listed.  The reduced pressure draws in the primary air.  The increased velocity allows a violent clashing of fuel and air which mixes them and matches their velocities.  

You can aim the motor at a straight tube as Mikey has done with his burners.  This requires higher input energy to entrain air.  As such, his burners run a smaller orifice at a higher pressure to run neutral flames. 

In terms of fuel output(possible heat output), a smaller orifice at a higher pressure can match a larger orifice at a lower pressure.  What matters is how well the fuel is burned and how much energy per time (eg btu/hr) is being sent through a given area.  Any resistance or turbulence impedes this throughput.  Energy in = Energy out.  The less of it lost/wasted, the better the performance.  

You can point that kinetic motor at a converging/reducer inlet at the beginning of a straight tube like Ron Reil, Larry Zoeller, Rex Price, and I have done.  This has the benefits previously discussed.  They can run larger orifices at lower pressures which can allow more energy/time.

You can add the diverging mix tube which is less resistant then a straight tube.  Even less of the motive fluid's kinetic energy will be required.  More air will be induced and the FAM will be delivered at a lower velocity/higher pressure.  This can allow even higher energy/time.  I think the outlet pressure also helps push the stream through upstream resistances.  The only reason it is not employed more often is because there is nothing readily available which has the proper dimensions and can withstand the heat requirements.  

My inducers crank the velocity down the mix tube as I have increased the throughput.  This high velocity blows the flame off the burner.  I then employ a larger than normal nozzle to put on the brakes.  This is some of that loss/waste of energy I talked about.  Throughput could be increased even still if I could limit/eliminate this step by slowing it down gently.  

On ‎6‎/‎10‎/‎2019 at 10:36 PM, Another FrankenBurner said:

I would like to see what it would do with the proper outlet taper.

Here is my latest experiment v55:

V46 1/2" inducer with the expanding mix tube.  Eight hours of printing, a few minutes of running before melt down, big smile on my face.  I knew what was going to happen and it still excited me when it happened.  He delivers a highly oxidizing flame with the 035 jet which is better performance than my 3/4" pipe burner.  He can not be categorized with the pipe burner sizing.  A throat of 1/2 inch pipe and an outlet of 1 inch pipe.  

I had not seen that study on burners, thank you for sharing it.  I will give it a thorough read.  

Hopefully that was all legible and I didn't say anything stupid.  We have the potential energy of the cylinder, the kinetic energy of the stream, and the heat energy of the fuel.  It's hard to keep it all straight in conversation when talking about more than one.

Frosty:  You don't have to measure water column against a vacuum but you can and I was.  I regularly measure the positive water column pressure of natural gas against ambient pressure.  When I measured the throat of the venturi against ambient, I was measuring vacuum.  Water can be used because it is a very light vacuum.  For bigger pressure difference mercury is used because of it's higher density.  My vacuum pump is said to pull to 29.5 inches of mercury which is ~401 inches of water.  Mercury also has a lower vapour pressure so it won't boil off under the deeper vacuum like water will.  Thankfully I have Bourdon tube and analog/digital electric gauges for work.

I will play with inducing air from the sides of a curved inlet.  Sounds like a fun adventure.

[D.Rotblatt]

I'll be doing some testing tomorrow.  Both with single burner and with NARB - I'm wondering how they work differently.

From looking at the article referenced by JWMelvin (thanks for that!), and examining the Amal burner, a 2 degree flare seems best for the injector.  The 1:12 flare is actually about a 4 degree flare which is quite a difference.  Of course a nozzle flare and an injector flare are different.  

On 6/16/2019 at 11:41 AM, Another FrankenBurner said:

Here is my latest experiment v55:

I'm liking that!  I wonder how that will work on a NARB - it would stay nice and cool....

Just some thoughts, real life experiments tomorrow!

Dan R

[Another FrankenBurner]

The 2° in the paper JWMelvin pointed out is the angle to center line which is only half of the 4° included angle of the taper.  The 1:12 taper is an included angle of 4.76364°.  The standard venturi outlet has an included angle of 5°.  I usually use the 1:12 taper just because I've been reading about it for so long but I think anywhere in the 4-5° range will not cause turbulence through the expansion.

I've been playing around with it as well.  First I did the outlet on v46 which is posted above.  Then I printed a partial length tapered adapter for v46 to upsize to 3/4 pipe.  

He induces more air then his 3/4 pipe burner counterpart.  

Then I printed a full length(8x) taper from 1/2" pipe down to a smaller throat.  

He attaches to 1/2" pipe as well.  He runs the 030 tip with a neutral flame.  His v46 counterpart is a better flame but when I open the throat a little bit, it will be superior.

It still has the odd business of pipe after the fact.  If only I could cast him in iron.  The pipe after him makes him longer than v46 but it would be needed as a thermal buffer.  I used a 4 inch section of pipe to add nozzles.

Thank you again for the paper, JWMelvin.  It has confirmed my findings and showed me that I am reinventing the wheel for the most part.  I like that.  The people before us were smart folks and we are spending all this effort trying to figure out what was figured out a hundred plus years ago.  Not unlike the entire blacksmithing hobby. 

I had just started measuring burner pressures as a method of measuring burner efficiency.  In the paper, the level of static pressure was also their measurement of burner efficiency.  Once again, figuring out the already figured out.  Good stuff.

We are still working on producing the v46 inducers for supply as they are practical for home builders and make a hot forge but I will continue to tinker with the wasp waist.  They will be superior for the NARB folks as they deliver at the higher static pressures.

 

[jlpservicesinc]

Great work and love all that has been going on here.. 

As an addendum for casting.  Pipe can be forged pretty easily to the required shape/profile.   Also metal lathe work (prototype) and with CNC lathe work, they could turn out maybe 1 every few minutes..  Crazy fast. 

 

[Another FrankenBurner]

We are talking about all the possible ways that we might be able to produce something with what we have.  The other part of the fun, how can it be accomplished?  More reason to tinker.  

 

[D.Rotblatt]

I tried 6 different configurations.  3 funnels @ .5, .75 and 1.0" deep with a 2" OD on the funnel.  Also using the same .75" funnel as the top, I made two with a wasp extension to the bottom.  One with a 2 and one a 4 degree slope.  I didn't think, and now realize that the 2 degree is the 1:12 and the 4 degree is steeper.  All finish on a 3/4" x 8" pipe.

I tried them on a plain single burner and my modified NARB with 1/8" holes.  

The most exciting thing about these injectors is the choke.  It's simply a cone placed around the jet. The pipe for the jet is held in a clamp and can be moved forward or back, while the cone either allows or restricts the air intake.  On some of the burners it was very finicky and short range of movement (maybe 1/4") caused a a huge change in the mixture, but on the 4 degree wasp (which I'll show below).  On that one it seemed to be effected much further away, and had maybe a 1/2" of movement. This allowed for easy fine tuning of the mixture...something I consider important.

 

The best of them was the Wasp waisted one with 4 degree sides.  The actual inlet size is only .54" but it seems to draw more air then the others.

On the NARB I had to use a .041 mig tip to get a neutral flame.  The flames were very even.  .048 was too large and produced greenish flames, while .035 produced sharp blue flames that pushed away from the burner.  Pic below:

4 Degree Wasp with .041 mig tip at 5lbs pressure:

     

Compare with a Real burner and #60 nozzle hole (which is about .040") in a pipe (standard setup):

With a single burner the 4 degree wasp injector had the flame with the least central cone.  This pic is with a .041 tip.

The same injector as above with .030 mig tip:

As above without choke:

Conclusions: first, they all worked.  The 4 degree wasp was the most stable with a single burner.  I was able to run it with the burner nozzle furthest back.  With the NARB the difference was most noticeable.  The 4 degree wasp pulled the most air and had the most oxidizing flame.  It required putting on a .041mig tip to bring the flame to a neutral mix.  The choke worked great on all of them, and is a viable method to adjust the mix.  I noticed very little difference between using a choke and not using a choke in the flame characteristics.

 

4 degree Wasp Injector:

 

Back to the virtual drawing board....got some other thoughts to try!

DanR

 

 

[Another FrankenBurner]

Those NARB flames are looking really great.  Can't wait to see what happens when you point them at a forge.

[D.Rotblatt]

Update: Played around with some other burner designs, and looked at the last batch.

All injectors were tried on an 8" x 3/4" pipe either ending in a nozzle or attached to the NARB.

 

Correction on the last burner test:

Turns out the 2 degree wasp was looking bad because the flame was so lean, this burner really pulls air.  Moving up to a .041or .044 tip really made a difference, and it seemed better than the 4 degree wasp.  This wasp burner has the biggest intake hole at .685".  It definitely pulled the most draft.

New injectors:

I tried a longer burner at 2 degree slope.  Basically I elongated the 2 degree section of the 2 degree wasp with the same intake funnel.  Because it's twice as long, the intake hole is only .545" vs .685" diameter.  This was a very stable injector and showed easy adjustment with the choke. 

On a single burner the 2 degree wasp performed the best. On the NARB I got good results with anything.  Seems it is a much more stable platform for the flames.  I ended up switching mig tips between .044, .041, .033, .030 until I got a neutral flame with maximum air allowed.  The largest flame I got at 5 lbs was 5/8" with the 2 degree Wasp injector/.044 mig tip.  The long 2 degree injector was happy with the .041 mig and had a 19/32" flame - a little smaller then the shorter 2 degree.  

Conclusions (at present): the shorter 2 degree wasp seems to work best, while the longer 2 degree wasp was also very stable.  The shorter had a larger opening which allowed for more air and thus a larger mig tip and more BTU.  The wasp shape definitely pulls more air then a simple funnel.  A larger opening is better.  This opening is limited by the ID of the 3/4" tube (.84" or so).  Two questions come out of this: 1) is this the most efficient shape to maximize air flow, and 2) is there some way to cause a vortex, and would that help or hinder air flow - yes AFB, your spiral intake is genius, but I'm still wanting to see if this can be sand cast.

Next up: Play with some short designs that have large intakes and wasp bodies.

 

Short 2 degree Wasp injector @5 lbs, .044 mig tip:

 

___

Close up of flame:

 

___

Long 2 degree Wasp injector @5lbs with .041 mig tip:  

___

Closeup of flame:

 

___

Long 2 degree Wasp Injector, @10lbs:

 

 

 

 

[D.Rotblatt]

On ‎6‎/‎18‎/‎2019 at 7:37 AM, Another FrankenBurner said:

I am reinventing the wheel for the most part

Actually, there was nothing in there about that spiral intake....that's out of the box! 

[Another FrankenBurner]

Those are looking great Dan.  The outlet taper is fun to tinker with.  It dramatically changes induction.  I am printing another experiment today.

I know exactly what you mean about the outlet diameter limiting the inlet diameter, I am fighting with that as well.   The inlet diameter is the major dimension controlling throughput.  Just to state the obvious, as you increase mig tip size, if pressure and flame quality are constant, your fuel usage and output energy increase.  The difference in fuel usage between the 035 and the 044 will be quite noticeable.  In pipe burners, this would be comparable to stepping up a couple of sizes.  

To clear something up, when you say 2°, are you meaning the angle to center line(red)?  (Not the included angle, yellow)

Thank you for the kind words.  I have tested with/without the fancy intake with the outlet taper and it is still doing great things.  About a single mig tip size difference.  I think it is all about causing a vortex.  There is probably a simpler way to accomplish this but I haven't thought of it.  I think streamline is key here, anything aggressive hinders flow.  Simpler would be better even if it didn't look as good.   

I am more than willing to abandon everything I have done to follow a better path if we find one.  

 

[D.Rotblatt]

1 hour ago, Another FrankenBurner said:

To clear something up, when you say 2°, are you meaning the angle to center line(red)?  (Not the included angle, yellow)

Yes, the red dimension.  Seems I've been making all my tapers twice as wide as necessary for decades.  I always think of 1:12 on roofs and such, so when I first made tapered nozzles 20 years ago or so, I didn't use the included angle, just one side.  Probably explains way the flame pulled so far into the nozzle and burnt them up over time...sigh.

"Fancy Intake"...  I like that name!  Anyway, I just added your "Fancy Intake" (best I could guess from your pics) to the 2 degree wasp burner.  I put an open top so I can use my same moveable choke system.  We'll see if there is any difference.  I'll print it up today or tonight.  If it works it makes a much more difficult sand cast, but with the open top end it might be doable.  Cool thing about the 3d printer is I can make a core mold with it...haven't done that yet so that's kind of an exciting thought!

1 hour ago, Another FrankenBurner said:

I know exactly what you mean about the outlet diameter limiting the inlet diameter, I am fighting with that as well.

Yup...I just want to go to a 1" pipe...but that kind of defeats the point. 

DanR

[D.Rotblatt]

2 hours ago, Another FrankenBurner said:

The difference in fuel usage between the 035 and the 044 will be quite noticeable.

The wasp style was very stable at nearly 0 pressure. Low enough so the flame went lazy orange.  If true in a forge, that means I can just turn it down lower and it has a higher upper end!

[Another FrankenBurner]

1 hour ago, D.Rotblatt said:

I just want to go to a 1" pipe.

it has a higher upper end!

Somewhere Tim Allen is grunting.  How much burner are you after?  What are you forging over there, anvils? 

Looks good.  I am looking forward to the report back.