Another FrankenBurner

3D printed plastic burner experiments (photo heavy)

Recommended Posts

I couldn't resist :)

Matt.

Look up vortice and laws of vortical flow; streamlining; turbulence; drag; and Bernoulli's Principle, for the science behind NA burners.

Share this post


Link to post
Share on other sites
14 hours ago, Another FrankenBurner said:

A nice little twist of my own.  It's usually Frosty who likes the play around with words.  Thanks Mikey.

Mike has his own spin on things. I try to keep friction low you know, don't want anybody to get burned.

Frosty The Lucky.

Share this post


Link to post
Share on other sites

Frosty: I have written a few responses and deleted them.  I got nothing.  Your wordcraft is strong.

I am still awaiting mig tips so I have been playing with dynamics.  I have been focused on more power to the vortex.  Most of the experiments were flops.

I tried a cone drop shape on the accelerator block.  This caused less vortex and more push.

2.7_11.jpg.6a6bbb4bb1db4ee5c9042cb4e8566c67.jpg

I tried curved airfoil ribs.  First in similar dimensions.  Then in a constricting pattern.  Then in a very aggressive angle.  All versions induced less air.  The similar dimensioned curved ribs showed turbulence in their curved section with smoke.  The constricting pattern blocked too much air.  The aggressive angle got in the way of the vortex I think.

645366772_curvedribs.jpg.4fd754bdafe3b17ae89b8493f51b64c9.jpg

Then some vortex success with another rib.

2.7_15.jpg.73096992d5bdae65cd6232639b0a2456.jpg

More powerful vortex.  Too much.  It comes out the pipe rotating very fast and spreads.  If the pressure is higher, the center of the flame is void and a full rotation can be seen in the flame.  It is louder and has a scattered secondary flame.  It induces less but I did not change the length of the ribs to keep the 50/50 ratio.  If a longer mix tube is used to calm the rotation, it doesn't induce as much.  Mesmerizing to watch the flame.  Here is a low pressure shot:

vortex.jpg.e2de00ef792e4a123378f354ba642b98.jpg

 

In my playing, I discovered that 2.7.8 which has 1 inch long ribs does better then 2.7.9 with 1/2 inch long ribs.  I am now printing a version with 3/4 inch long ribs.  I am up to 2.7.17 with all the vortex play and 2.7.8 is still holding it's place.  It induces a lot of air, it forms a good vortex in the inducer, it mixes well, it has good range, and it can do all of this at very low input pressures.  Now we'll see what that does with a bigger jet.

Share this post


Link to post
Share on other sites

Have you tried including a sliding choke on the air chambers during your experiments? Since such a choke is a safety measure, it will end up being included on some burners anyway, so you might find it timely to to including one now :)

Also, I find the fact that that much rotation can even be maintained in a burner's flame to be a strong indication that you are on the right path.

Share this post


Link to post
Share on other sites

All of these burners have a sliding choke on them.  As you said, mostly as a safety measure.  I do partially close the air inlets once in a while to tinker but usually they are wide open.  

I have enough vortex that I think it needs to be toned down but you think I am on the right path.  You have previously stated the more the better.  What is your thinking on that?  Is there a limit?  What is the end goal with your vortex burners?  

Share this post


Link to post
Share on other sites
2 hours ago, Another FrankenBurner said:

You have previously stated the more the better.  What is your thinking on that?

Its like acceleration, braking ability, or power steering; it just ain't possible to have too much. The more you have, the more carefully you must use it--or end up in a ditch. But less is the wrong answer for sure!

There are three ways to control stronger input:

Longer mixing tubes.

 Larger flame retention nozzles.

Internal fins inside the mixing tubes.

Having said all that, if you think I'm over selling the case, you're totally right. Good judgement is priceless, BUT it is so dang easy to overlook the obvious, and end up tripping over facts at our feet! Some times we have to hold apparent inconsistency in balance, to get a useful outcome :)

Share this post


Link to post
Share on other sites

If only punny wordsmithing paid better. <sigh>

2.7.11 fins are too short in my eyeball gaugementer, it can't draw enough air.

I like the flame vortex provided you can get enough FAM per second burning to make good heat. It puts paid to impingement in the forge chamber, work even. A strong vortex is how high temp chemical erosion is controlled in oil boilers. The flame doesn't touch the refractory, only the boiler tubes. 

Of course there's such a thing as too much. . . Anything. Worse you're not talking about the other control method. Larger jet lower psi. will control excessive velocity and put more FAM per second in the fire. Hmmmm?

Another thought is becoming evident to me here. The more you try to control the vortex the less it behaves as we wish. The (Aerospike) type intake cone is a bust though a version MIGHT make a good jet mod. 

The more severe the air foils become the worse the performance. I think you're down to minor most here. Remember the intake air WANTS in fact MUST form a vortex. Trying to force it causes turbulence as seen. Yes? 

I'm thinking minor changes to the inside of the existing fins on 2.7.2, 2.7.3 is almost reversed for an air foil. Increasing either the leading or trailing edge almost to trim tab or even flaps profiles just looks wrong.

I'd be looking at low aspect wing profiles. The bottom surface maybe almost flat and the upper surface only exaggerating the line of the cord from leading to trailing edge. The slant you're putting on the fins looks like a delta wing. Reversing it did exactly what reversing the sweep or camber does for combat aircraft, made it more unstable. Controlled instability is what makes combat aircraft maneuverable. A burner needs a smooth FAM stream. Yes? 

https://images.search.yahoo.com/search/images?p=wing+profiles&amp;fr=crmas&amp;imgurl=http%3A%2F%2Fwww.koryoswrites.com%2Fwp-content%2Fuploads%2F2015%2F01%2F1022px-Wing_profile_nomenclature.svg_.png#id=0&amp;iurl=http%3A%2F%2Fwww.koryoswrites.com%2Fwp-content%2Fuploads%2F2015%2F01%2F1022px-Wing_profile_nomenclature.svg_.png&amp;action=close

Frosty The Lucky.

 

Share this post


Link to post
Share on other sites

The 2.7.11 fins are too short, shorter then 1/2 inch.  I took 2.7.9 and made versions with 1/2, 3/4, and 1 inch length ribs.  The 1 inch ribs induce more air and more vortex. 

I suspected when printing the more extreme ribs that they would be poor performers.  I agree that brute force can do nothing here.  Now I am trying to learn what the vortex wants so I can feed it properly.  Make him happy to exist.  In the smoke tests, 2.7.15 has the strongest vortex.  2.7.8 has clearly visible vortex with smoke but he also induces much more air.

2 hours ago, Frosty said:

I'd be looking at low aspect wing profiles. The bottom surface maybe almost flat and the upper surface only exaggerating the line of the cord from leading to trailing edge. The slant you're putting on the fins looks like a delta wing. Reversing it did exactly what reversing the sweep or camber does for combat aircraft, made it more unstable. Controlled instability is what makes combat aircraft maneuverable. A burner needs a smooth FAM stream. Yes? 

I will have to think about this and research to fully understand.

I have played with many rib profiles and 2.7.2 has been the most successful.  When monitoring smoke, it flows around 2.7.2 ribs without turbulence that I can see.  I intend on small changes to it soon.  

I have a few more big changes to try first.  I am still playing with the extra rib but bringing the rib/inlet ratio to 50/50.  I am also making the rib length 1 inch.  

2.8.jpg.6a8d5c8bd1fbb7547508d58147b18ef2.jpg

I am also playing with 3 ribs with the 2.7.2 rib profile but decreasing the helix pitch length to see if it hurts or helps.

2.7_19.jpg.3f618d2db5b095c5e42ba82960f8ad1e.jpg

I have not printed either yet.

 

 

 

Share this post


Link to post
Share on other sites

Remember the vortex isn't the goal, inducing air and mixing it with fuel is. The more FAM you can get in the forge per second the more heat. Assuming the correct fuel air ratio of course, that's #1. a MUST.

A good vortex is undoubtedly an important factor for performance I just don't think it's the most important.

I'll be surprised if a 4th. rib will improve anything. Been wrong before though, looking forward to it.

Frosty The Lucky. 

Share this post


Link to post
Share on other sites

I'm on the same page.  I have not lost sight of the burners purpose.  I was just tinkering with vortex as I wait for bigger jets.  I was trying to see how much is too much, why, and how to get there.  

Share this post


Link to post
Share on other sites

It's really hard to sit here and watch someone else with the talent and tools doing so much really cool experimenting. This is all just so wicked cool.

I'm thinking the thick cap with the rounded inside edge could be flat and thin instead. Have you taken note of how the smoke behaves near the cap? The aerospike structure didn't work and my intuition says it should have been beneficial. Now I'm wondering if anything in that area is a good thing.

Frosty The Lucky.

Share this post


Link to post
Share on other sites

Intuition tells me that you need thin edges on the outer edge of the ribs; not just the inner trailing edge. After all, you aren't attempting to provide lift to a plane wing.

Share this post


Link to post
Share on other sites
19 hours ago, Frosty said:

It's really hard to sit here and watch

Each print costs less then $1.  If you can explain things clearly or put up drawings of your ideas, I will CAD/print them and report.

19 hours ago, Frosty said:

This is all just so wicked cool.

Agreed.  It is hard not to be enthusiastic about how cool it is.  I drive my wife crazy routinely.

19 hours ago, Frosty said:

I'm thinking the thick cap with the rounded inside edge could be flat and thin instead. Have you taken note of how the smoke behaves near the cap?

I think it could be thinner as well.  I originally made it thick so that the jet would be axially aligned and so the choke had a good flat to seal against.  I don't think much length is required for either purpose.  The smoke rolls down the radius and into the back of the vortex.  It seems smooth flowing.  Are you thinking skip the radius and have a thin flat disc instead?

19 hours ago, Frosty said:

The aerospike structure didn't work and my intuition says it should have been beneficial. Now I'm wondering if anything in that area is a good thing.

I have not been fair to the aerospike yet.  The ribs were too short on that model and I suspect the spike too large.  The spike ended where the reducer began so the mig tip barely came out of it.  I was thinking it would kill dead airspace up by the accelerator.  Instead it causes the streams to flow in and straight down the mix tube.  More forward push.  It doesn't induce as much air but it's output velocities seem higher.  I had already created another version which has a thinner disc with much smaller spike.  Part of the spike will be the jet itself.  

 

You were right about the four rib version.  For the most part, there isn't much change at all.  I think it may induce a little more vortex and a little less air but, if so, it is small enough that it is hard to tell.  Version 2.7.8 is still the golden boy.  Changes are variations of him at this point.  I still haven't printed 2.7.19 with the extra twist yet. 

You were also right about the 030 mig tip.  Version 2.7.8 runs neutral from 1 to 10 psi with the stepped/flared nozzle.  Above that, it begins to go purple.  A 1.25 inch diameter flame at 1 psi is pretty awesome.  If I put the smaller nozzles on it, it can be run on the peg still.  I tried the 035 but that was too much.  I got a neutral flame above 15 psi, a bit much.  I think the 030 is a good balance.  

 

15 hours ago, Mikey98118 said:

Intuition tells me that you need thin edges on the outer edge of the ribs

I was wondering about this one.  Originally I went with a standard symmetric teardrop airfoil.  I will be playing with airfoil shapes.  If you describe it and think it might be a good idea, I will try it.  

 

Share this post


Link to post
Share on other sites

Another FrankenBurner what about printing a  fan blade like a 3 blade boat propeller that is a couple millimeters less of a diameter of the pipe so it can rotate. Would that help with what your trying to do? Just trying to figure out a way to insert it into the mixing tube and where at within the length would be the problem I see with doing this. I have a friend who had a 3d printer for a while and he printed a box with gears in it that turned and there wasn't any assembling any pieces of it it wort just as it was printed. If there was a way you could do some type of cylinder insert where the propeller was in the center and spun like the gear box my friend did and the top and bottom of it were just hollow allowing the air to flow through it turning the prop it might work. But please tell me if the theory of my concept is wrong and maybe why if you dont mind. I am new to this and trying to learn as much as I can.

Share this post


Link to post
Share on other sites
1 hour ago, Another FrankenBurner said:

If you can explain things clearly or put up drawings of your ideas, I will CAD/print them and report.

I'll see if I can draw my thoughts. Being able to test might put some ideas to rest in my head. 

 

1 hour ago, Another FrankenBurner said:

I drive my wife crazy routinely.

Me too but Deb married me and I was as crazy then, I'm just TBI modified crazy now.

1 hour ago, Another FrankenBurner said:

Instead it causes the streams to flow in and straight down the mix tube.

Interesting effect, it stops the vortex till it hits the tube? Did you know you can cause two vortices in a tube that are moving opposite directions but have their rotations coupled? I'm thinking we're seeing something like it with this test. This site describes it pretty well and has pictures. https://www.instructables.com/id/The-Hilsch-vortex-tube/

Maybe a flatter disk and a more acute aerospike that ends with just the tip of the jet protruding. 

Darn, I can't quote Mike in edit. 

Intuition is telling me an airfoil is a good way to increase both intake and vortex motion in the intake. A wing lifts because the pressure on top is lower than below but the shape of the foil causes both halves of the air stream to rejoin at the trailing edge. What causes the lower pressure is the air is traveling a longer distance but almost without friction because of the boundary effect.

If the inside of the rib follows the circumference of the intake bell and the rib's "leading" edge is rounded like a wing and it's curve returns to the inner surface. The air on the outside surface will be flowing more towards the center of the vortex in a tangential current. It's not being pushed, it's being drawn by reduced pressure and higher velocity.

It may not be much but it'd be increasing the velocity of the vortex at the outside edge where it will multiply as it's drawn to the throat.

A round leading edge air foil lift on the outside and a sharp trailing edge to minimize or hopefully eliminate turbulence. 

Does that make sense?  

Frosty The Lucky.

Share this post


Link to post
Share on other sites

Matt Watson: What is the intended goal of your idea?  I think it's a case of "There is no free lunch."  Your idea would require energy and would be a partial blockage of the mix tube.  It takes very little blockage to severely reduce air induction.  Also, 3d printed, there would be enough friction, it probably wouldn't rotate with just FAM flow.  

Mikey suggested fins inside the mix tube but they would be intended to purposefully remove some energy if we had a vortex which was too strong at the flame end.  

Any time I try to aggressively control anything, it is more harmful then helpful to performance.  The best performance has been when the geometries go with the flow.  All shapes are designed to cause as minimal drag as possible while encouraging flows to move how we want them too.  Doing any more takes energy which reduces induction.

You say you are new to this and learning as much as you can, read Burners 101.  It is long and there is a lot of information, take your time.  I have read it twice and learned from it, both reads.  If after that, you are still hungry, read the T burner thread, Mikey's book, Ron Reil's pages, Zoeller's pages, the Hybrid Burner pages, and Wayne Coe's pdf's.  There is a lot of information out there.  Just remember that some of it is aged.

Frosty: Even crude hand drawings with a good explanation, will work.  Nothing too crude though, I don't want you to get moderated.  :P  

I don't think I am creating the very cool dual vortex.  I think the short ribs and lack head room cause the streams to flow through so fast that it is almost linear flow.  I will play with it a little more with smoke and really pay attention.  I saw a severe drop in air induction so I didn't play with it much.

I am pretty sure I have a good picture of the airfoil you describe.  I understood how lift works with wings but when it came to burners, I didn't know if or how any of it would help.  I took the safe approach and went symmetric.  Increasing the outside velocity makes sense.  The four rib model with smaller air openings absolutely increased vortex because it increased the induction velocities but at a cost of induction volume.  Here, a drawing would be great so I can get it right.  Definitely worth a shot.  

With the vortex, the stronger it is, the more the air is induced at a lower angle of attack.  The streams line up.  Said backwards, the weaker the vortex, the more likely the air is to come in around the ribs from all angles.  Some of it, at the centers of the inlets, induces straight in towards the accelerator.  If we get the outside air streams to higher velocities, it naturally changes the direction of the straight induced air into the inside of the next rib.  That was a stumble of words, did that make sense?

 

Share this post


Link to post
Share on other sites

I wasn't suggesting the aerospike was making a second vortex like a vortex tube. I was suggesting it was altering the natural vortex in the burner intake in a similar manner as the cone in the hot end of a vortex tube. As I recall the cone causes or helps the cold molecules migrate to the center and reverses the cold vortex's direction in the tube towards the cold end. 

I was just struck by the similarity in shape, position and the interesting effect on the vortex so I brought it up. Hoping it increases the general befuddlement, a boy has to have a hobby.

Matt: we're not ignoring you, we're just lost in out own caverns of imagination here. Installing a rotary impeller to induce a vortex is how it's done in our Burnham oil boiler but it's a gun burner, the energy is supplied by the blower. 

We've discussed using something to increase the vortex but just haven't come up with an idea that didn't cost too much in air induction. One that can take the heat at the nozzle end where the velocity isn't desirable might be a perfect spot. It's be an interesting flame holder.

Something else to think about. A boat screw isn't even close to the right shape, they're designed to turn rotary motion into thrust in water. Water is what, 80 times as dense as air and requires a very different geometry even though the theory and rules are the same. 

If you wish to turn linear motion into rotary as in cause intake air or a stream in a tube you want to look at wind turbine geometry. I've always wanted to experiment with those spinning beehive shape caps on air vents you see on rooves. Modifying air flow is a really huge subject, I have no doubt there are better ways of doing what we're noodling with here and no telling where it'll come from.

Frosty The Lucky. 

 

Share this post


Link to post
Share on other sites
41 minutes ago, Frosty said:

Hoping it increases the general befuddlement, a boy has to have a hobby.

As stated by someone somewhere else recently, a good rabbit hole can be fun.  I will be playing with the dual vortex on the side just because it's cool.  I still happen to think the tornado in coke bottles is cool though.  Luckily I have a daughter to give me a reason to build those again.  I even get to call it teaching.  

I enjoy working within the confines of naturally aspirated.  We could add energy and do a lot of cool things, but working only with the potential energy of the fuel is challenging and entertaining.

Share this post


Link to post
Share on other sites
44 minutes ago, Another FrankenBurner said:

As stated by someone somewhere else recently, a good rabbit hole can be fun.

Now you're citing hare brained statements. Where do you think your parents went wrong? I don't think mine ever figured it out.

Yeah, vortex tubes are cool and HOT at the same time. 

I like the home school type experiments, good science does't need to be big, shiny and expensive. 

Frosty The Lucky. 

Share this post


Link to post
Share on other sites

Well, Matt's suggestion could work, but would be way more work than is warranted--in normal construction--but is well worth pursuing in a printed version. At present you have a large solid end cap. If you you include the ribs-as- airfoils idea by turning the end cap into a hub and wheel structure...

Share this post


Link to post
Share on other sites
1 hour ago, Frosty said:

Where do you think your parents went wrong?

I think part of it is that when I asked why, they pointed me in the direction of the answer.  

My daughter is home schooled.  I wanted her to graduate thinking that learning is a great thing.  I sure didn't learn that in school.  I think we are born scientists, curious about the world around us.  Unfortunately, that goes extinct in some people.  With my daughter, we encourage it and get out of the way.  On a regular basis, she becomes the teacher.

Who knew you could learn so much from mouse trap catapults, water rockets, and paper airplanes?

51 minutes ago, Mikey98118 said:

If you you include the ribs-as- airfoils idea by turning the end cap into a hub and wheel structure...

Are you meaning draw air in from the back with a fan looking assembly?  

Share this post


Link to post
Share on other sites

I've only ever known a couple home schooled kids who weren't years ahead of public schooled kids like me. The closest I ever got were flash cards and Mother keeping an eye on me so I didn't goof off. 

Interesting idea Mike, shaped something like a jet engine compressor fan maybe? I'm sure it'd enhance the vortex in a linear burner. Including a screw type variable pitch mechanism would make the choke. That or an iris mechanism. Hmmmmm, another tunnel for the bunny to explore. 

Frosty The Lucky. 

Share this post


Link to post
Share on other sites

I think your rabbit hole is producing a nice crop of workable ideas so far. I'm only waiting for it to slow down before dumping another packet of seeds down it :D

Share this post


Link to post
Share on other sites

I tinkered a bit more.  I played with 2.7.11, 2.7.15, and 2.7.19.  

I gave bad data when it comes to 2.7.11 which is the aerospike version.  With the shortest ribs of the bunch, it induces around the same amount of air as golden boy 2.7.8.  It is partly unstable at start up.  It has visible high speed rotation in the flame.  The rotation causes the flame to come out in a cylinder. The flame is impossible to blow out with my lungs.  I can blow out all other versions.  It is a weird flame, it seems to oscillate.  I also noticed during the smoke tests that the smoke which rolls in from the side of the ribs forms it's own small vortex on it's way to join the main vortex.  I definitely want to play with the aerospike a bit more.  

Here is a low pressure flame in the 1.25" nozzle with the 030 mig tip:

small.jpg.1c6c17aaab308d4eae3d7fd9b2088fd0.jpg

Here is a 5 psi flame with the 030 jet:

big.jpg.412dd33c7509f00bc4fe277483ae9ef3.jpg

Here is a short video to show the small smoke vortex:

 

2.7.15 which has the 4 ribs which were short produces the greatest vortex.  It is visible in the flame.  The reduced air inlet area causes the induction air to rush in but it reduces induction volume.  Here is the best image I could get which sort of shows the rotation.  This is with the 023 jet:

twist.jpg.f23418ca68613466c95632ba25d61cb2.jpg

 

I also played with 2.7.19 which has the extra twisted ribs.  It induces better vortex then 2.7.8 without decreasing induction air like 2.7.15.  I may play with more twist a bit more.  Unfortunately I broke it when switching out mig tips.  

Share this post


Link to post
Share on other sites

All the photos and the video are impressive. The gas pressure is so low that the flame is barely flame reaching beyond the flame retention nozzle in the first photo  (probably considerably under 4 PSI), and yet it is very strong. The flame in the middle photo Is what I consider perfectly centered in the neutral range; you can tell by its light blue tint. I would not expect it to generate anymore scale in a forge than a lightly reducing flame. It would be interesting to see what effect internal finds in the flame nozzle would do to that combustion vortex you have coming out in the third photo.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.