Gas lens screen

[Whiskeymike]

I'm wondering if anyone has tried putting a screen in a NA burner after the gas introduction to force mixing of the propane and air.  Much like a gas lens on a tig torch flows the argon.  

Mike

[Buzzkill]

It has been tried on a NA ribbon burner at least. Details and photos on page 2.

https://www.iforgeiron.com/topic/62224-my-forge-development-thread/page/2/

In general my experience with NA burners has been that anything in the mixing tube or at the flame end of the burner that causes a restriction decreases the ability of the burner to induce air and therefore tends to produce a richer than desired fuel air mix. 

However, we're seeing good results from redesigning the intake end of the burners to get better mixing and greater air induction.

https://www.iforgeiron.com/topic/61034-3d-printed-plastic-burner-experiments-photo-heavy/

 

[jwmelvin]

Yes a flat screen didn’t seem to restrict flow much at all. I think I have pretty good mixing so it didn’t offer much benefit either. I was able to stack a few layers over areas of relatively high flow to help even it out and that did seem effective but I think I can accomplish the same thing more efficiently through diffuser design.

As for a jet nozzle, using rolled screen in the mixing tube has a dramatic effect on flow and choked the burner. It was no good. 

As buzzkill says, the vortex-generating inducers seem to be working well to achieve good mix. With a forced-air burner, any drag penalty from mixing screen is easily overcome but with a naturally aspirated burner, it’s questionable. Perhaps with a simpler inducer a single flat screen could offer a meaningful benefit. I do have a plain metal funnel that I’d like to try as an inducer at some point. 

Edit: it’s also worth pointing out that my screen was generally in an area where the flow had expanded and therefore slowed. So it should have less restriction there than in the mixing tube where flow is faster. 

In a ribbon burner it seems you can use a large turbulence like impacting the plenum at 90° like Frosty likes. Not so much with a jet burner as the velocity seems more important there?

[Whiskeymike]

Great, thanks for the info.  I had searched the forums and came up blank.