Burners 101

[Mikey98118]

You might just be falling a little behind, Frosty

I still size burners by schedule #40 pipe internal diameters. That came from the narrowest point in wasp-waste burners; this has not changed. What has changed, just a little bit, is that fan-induced vortex burners can run two different flame retention nozzle diameters; no other burners, including naturally aspirated vortex burners, can use more than one flame nozzle diameter. So, for fan-induced vortex burners ONLY, it is true that flame nozzle diameters are the limit of burner output, rather than mixing tube inside diameters; its a very limited exception to a rule that normally applies.

1 minute ago, Mikey98118 said:

You might just be falling a little behind, Frosty

I still size burners by schedule #40 pipe internal diameters. That came from the narrowest point in wasp-waste burners; this has not changed. What has changed, just a little bit, is that fan-induced vortex burners can run two different flame retention nozzle diameters; no other burners, including naturally aspirated vortex burners, can use more than one flame nozzle diameter. So, for fan-induced vortex burners ONLY, it is true that flame nozzle diameters are the limit of burner output, rather than mixing tube inside diameters; its a very limited exception to a rule that normally applies.

It is still another case of circumstances altering cases

This only applies to fan-induced vortex burners; these must use more than one flame retention nozzle diameter. No other burner needs more than one flame retention nozzle diameter; not even naturally aspirated vortex burners. So, these particular burners prove the only exception to the rule--at present

[Another FrankenBurner]

There’s a loop?  No wonder I’m always confused.

[Mikey98118]

AFB, your naturally aspirated vortex burners are stronger running than any naturally aspirated design of mine. Nevertheless, they don't come up to the point where two different flame retention nozzle diameters are needed--yet. It would be fascinating to find out what the inclusion of angled fins at the air entrance might add to your design...

"Just when you thought it was safe to go back into the water."

[Frosty]

Did I miss  where you said you were discussing GUN rather than NA burners?  NOPE I just now skimmed the whole post and you specifically said "naturally aspirated burners" after almost every example. 

I'm wondering where this loop is Curtis, someone took an offramp to elsewhere.

Frosty The Lucky.

[Mikey98118]

I was not discussing gun burners per say. Nearly all gun burners use fans to push air into the burner; this causes the gas/air mixture flow to increase in both speed and pressure. The pressure increase severely limits how much flow the burner's flame retention nozzle can handle; it is largely self-defeating; or if you prefer it self-limiting.

This is why I call call vortex burners with moving impeller blades, which reduce mixture flow pressure to be fan-induced--not fan blown. A reduced pressure mixture flow, is much easier for flame retention nozzles to control.

[Frosty]

No, you were discussing NA burners and didn't say a word about inducing a vortex. You might want to re-read your past couple long how to posts, the "specs" aren't jibing. 

Frosty The Lucky.

[Mikey98118]

You are right, Frosty. I need to go back and make things clear.

Vortex burners with moving impeller blades at their air entrances (ex. funnel openings), as you get from installation of modern axial computer fans, create two differences from other linear burners, whether naturally aspirated, or fan-blown (blades that push air forward):

The first, and desired difference, is that those impeller blades swirl the incoming air around inside the funnel structure, creating much stronger vortex motion; creating fast swirl, with forward motion of about one-half the high velocity around its axis. But unlike any other method of increasing mixture flow speed, the air in that mixture is reduced in pressure.

The second thing that happens is that the low pressure area at the funnel entrance can suck fuel gas back into the fan, where it ignites, if you aren't careful to prevent that from occurring, by careful design.

This high-speed low-pressure gas/air mixture is then dumped into the flame retention nozzle at the far end of the mixing tube. When the fan speed is turned up to maximum, and the fuel gas pressure is turned up to match the greatly increased air flow, a second larger diameter flame retention nozzle is needed to handle this increased flow. Thus fan-induced burner output; not fan-blown, or naturally aspirated burners, can be rated by largest flame retention nozzle diameter. No other burner can be rated that way, because no other burner can be turned up anywhere near this high, without blowing its flame out.

 

[Frosty]

That's more clear Mike, thanks. 

Frosty The Lucky.

[Another FrankenBurner]

I’m confused. Not about what Mike is talking about. Just in general. Things are back to normal. 

[Mikey98118]

2 hours ago, Frosty said:

That's more clear Mike, thanks. 

I've been thinking about this stuff for so long, that I lose track of what all I have discussed, and what I merely intended to

AFB; so what do you think about adding fins at the entrance to your burners? I like you to be generally confused

[Another FrankenBurner]

When I imagine impeller vanes on my burner, I see a rework of the entire top half.

Air entering parallel the mix tube instead of perpendicular.

[Frosty]

3-4 vanes might be enough to induce a strong vortex.

Frosty The Lucky.

[Mikey98118]

On one hand, strong or weak is all too often in the eye of the beholder. When it comes to our own equipment, that eye may be too fond to be trusted

On the other hand, we could compare naturally aspirated equipment to bicycles. Fat tires replaced by narrow, three speeds replaced with 15, steel tube frames replaced by...well, you get the idea.

Then one day a motorcycle zooms by, and what we think about fast or slow, changes forever. Fans with impeller blades is the equivalent of a gasoline engine; much will change...but much will not

No shoe size fits all.

[Mikey98118]

So what limits do I foresee on the usefulness of fan-induced burners?

First of all, they should prove unworkable on ribbon burners, because such burners have plenum chambers, rather than flame retention nozzles. The greater potential pressure drop in a plenum chamber probably needs increased mixture flow pressure; a reduction in its pressure would only invite back fires into the mixing tube. I do expect small 12V fans to begin being employed on ribbon burners, but they should be squirrel cage fans, which increase the pressure of the burner's gas/air mixture.

I do not see fan-induced vortex burners ever become popular on small burner sizes (3/8" and less), because the whole point of these burners is control of small spaces; thus, supercharging them to get more flame is pointless.

So, we see the usefulness of fan-induced burners, while real,, is itself limited

No one shoe fits all.

So, what advantage do I think a little 12V squirel cage fan could possibly add to a naturally aspirated ribbon burner? Some increased pressure in the gas/air mixture, might be just what is needed to get better control of the flames, for complete combustion in a single flame envelope--or not; but if it works, it would be worthwhile.

[Frosty]

36 minutes ago, Mikey98118 said:

all too often in the eye of the beholder.

Confirmation bias is human nature and requires a n effort of will to temper.  For example my experience says adapting a NA burner to a multiple nozzle of whatever shape is just a matter of balancing flame velocity to inducer output. Might have to resort to a round plenum to maximize a vortex burner, adding a fan to induce a stronger vortex should only be a matter of tweaking. 

Of course that's just my opinion I COULD be wrong.

Frosty The Lucky.

[Another FrankenBurner]

I thought I was wrong once, but I was mistaken. 

[Mikey98118]

Being right is becoming so much more complicated; the more I learn the further away right gets. Soon it will require plane trips to come close.

[Frosty]

I hear you, the more I learn, the more I realize how little I know. I have to make do with pictures and descriptions of right.

Frosty The Lucky.

[Another FrankenBurner]

Where do we find those pictures and descriptions?  I’ve been looking but the Internet is a busy place. 

[Frosty]

That's one of my problems too. <sigh>

Frosty The Lucky.

[Mikey98118]

I have been trying to produce some of them. Alas, it takes a lot of study, before we are able to pronounce a few tiny little "facts." That study makes us see how inaccurate our "facts"are, and how limited. Thus, the more we learn, the less we know. Fortunately, myriads faced this problem before us, and we won't be the last. Misery does love company 

[Frosty]

Then once you have some hard numbers you get folks building the stuff who can't read a dimensioned drawing and make the piece. Not their fault, it's not something taught anymore. I found that out early, developing the first T burner. Ron was all about micrometer precision, follow the directions exactly and don't ask me basic build questions. Drove him a little crazy. Seriously, I keep running into high school grads who don't know WHAT a decimal is or how to read a scale, let alone calculate the area of a circle!

My approach was the opposite, I developed something that can be bought off a list and eyeball assembled and makes a reasonably effective burner.

Most questions I'm asked have answers like, bend the mig tip it's off center, trim it more it's running too rich, part of the liner is blocking the flame, etc.

One of the recurring problems comes from people using too small a mig tip and sticking it way down by or into the mixing tube. It's makes for a lousy T burner. Propane velocity MUST be about 2x to deliver the same volume as a 0.035" mig tip and being so far into the throat the distance to mix is poor. Of course at that velocity those big intake ports are supplying way too much air so it can't work close to what it should.

Look online and you see a gaggle of "experts" showing how to build T burners incorrectly, most even show the first sketches I posted to theForge.list years ago and I haven't seen one using the right size jet.

The thing that gripes me is they put MY name on all those bad copies!

Oh well, I put it out there for anybody to copy with minimal shop skills or tools so I guess it's okay.

Frosty The Lucky.

[Mikey98118]

I only suffered through bad copies with my name on them for the first five years, or so. After that, people started picking and choosing through my design principles, to make their own individual burners; this is exactly what I was shooting for

[Another FrankenBurner]

Anyone with a 3D printer could accurately and easily produce my burner, I originally thought.

You just need a 3D printer and the skill to use it. Oh and the stainless flasks and investment mix. And casting knowledge to get the vents right. And the ramp controlled kiln to vaporize the print without cracking the mold. And the furnace which requires you already have a burner. And a thermometer and flux to keep the metal happy.

So much for that original thought.

[Mikey98118]

Or, they can stick with a plastic air chamber, and avoid some of those steps. If the burner is handled carefully, I don't see that as a problem. Not that some idiot won't make it a problem, sooner or later.

The fans on my induced vortex burners, are also plastic, so I think about this stuff.