Liquid fuel nozzles

[noshell]

Hello again all.
I'm trying to design a good liquid fuel system and I can't think of a good design.

For good atomization it seems 100psi is a minimum fuel pressure for most burner nozzles available. This creates a problem as apparently even 300psi only yields around 30 percent more flow.

How have you guys got around this problem? I'm thinking of having a nozzle for idle and then another for more throttle, but it's not going to be a very smooth transition for obvious reasons. How have you guys got around this?
Some Russian dude on YouTube is using about 6 nozzles but this isn't very elegant and leaves you with only 6 throttle positions. Ultimately I want this engine in a bike, I don't want a finite number of throttle positions.

youtu.be/3qbFlg7qm0Q?si=V9H9eY6D30uUuvbf
My source of info about burner nozzles

[richardm]

I dont know of any one on this forum using a dual fuel nozzle system, But I once cogitated about such a system. In real life gas turbine / jet engines do use duplex fuel nozzles Its like one small nozzle embedded inside a bigger one. I realize those nozzle are out of reach to us but what is interesting is the flow divider unit. Many variations exist maybe a look at those could be a source of inspiration

On my side i thought about using an adjustable pressure regulator to feed the second nozzle

[racket]

I used a single spray nozzle in my bike jetandturbineowners.proboards.com/thread/1366/tv84-turbine-bike and eventually was able to have a very civilised throttling , but fuel pressure at full power was at ~750 psi which still left ~50 psi at idle for reasonable atomisation

[richardm]

Watch this from the 18 min. mark: I flew those engines for about 6000 hours and never knew that fuel pressure started at such a low value But it goes all the way up to 850 psi.
See how the fuel flow divider works
www.youtube.com/watch?v=J7DjdtiI3aw

[noshell]

Cheers guys.
These engines are bloody complicated haha

[noshell]

www.ebay.co.uk/itm/375093610803?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=alMbFsQ7RD-&sssrc=4429486&ssuid=0qSIhi1FTAO&var=&widget_ver=artemis&media=COPY

I'm struggling to find info on this type with the spring. Perhaps this is more what I need

[richardm]

This looks like a kerosene space heater nozzle. Wont work. Theses nozzles are air siphon type nozzles not designed to work with pressurized fuel
www.youtube.com/watch?v=oUxNzWsvCzc

[noshell]

The fuel flow divider seems to be the way.

I don't think it would be easy to make one that works well and is reliable though. Probably easier to have several solenoid valves.
Idk. Again, I need some more thinking time

[richardm]

How about a small primary nozzle with a on / off valve or solenoid for starting / idling and a larger nozzle with some throttling.
You 'd start and run idle on the small nozzle and then throttle the larger one to add more fuel . Constant pressure fuel pump. Throttle would have to be a bypass valve back to the pump or tank

[turbotom]

Spill nozzle? Make a "conventional" swirl-type pressure atomizing nozzle and tap into the swirl chamber from the rear. Manipulating the pressure/flow at this return tap line will control how much of the fuel will exit trough the atomizing orifice. The advantage is that the swirl velocity will stay high at all times, providing good atomization. Microturbo / PBS Saphir 5 nozzles work that way.

[jetric]

Yep these are the best nozzles that you can use as you run them at full pressure of 100psi from a bosch 044 efi pump and use the bleed from the swirl nozzle to control the amount of fuel spray. they are commonly known as BPS nozzles on oil burners. Here's some on Ebay,

www.ebay.co.uk/itm/303051891145?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=LomqfTWLQYi&sssrc=4429486&ssuid=dhvoJXG-RcC&var=&widget_ver=artemis&media=COPY

You also need the appropriate nozzle holder aswell.

Richard S

Sept 30, 2024 17:48:40 GMT -5 turbotom said:

Spill nozzle? Make a "conventional" swirl-type pressure atomizing nozzle and tap into the swirl chamber from the rear. Manipulating the pressure/flow at this return tap line will control how much of the fuel will exit trough the atomizing orifice. The advantage is that the swirl velocity will stay high at all times, providing good atomization. Microturbo / PBS Saphir 5 nozzles work that way.

[racket]

delavan.com/products/variflo/

[noshell]

You boys are champions, I've inquired about the variflo nozzles.
That sounds like the optimal solution.

[noshell]

The bastards wont respond to me
id have to make one. orrrr
bete.com/nozzle-configurator/?ncMdlS=PJ&ncFilterDensity=1&ncFilterSprayPatterns=Mist

[richardm]

Went to visit their site Looks like they dont sell directly on line. Probably just dealing with industrials..
But I dont see why you would use such a device. I think they must be quite fragile as the pin must be precisely aligned. Kind of easy to hit it and get it out of place ..
And how can this "elbow "shaped pin not interfere with the spray pattern ? I dont know , never seen one at work But i do know that you dont want fuel streak from a bad nozzle. That streak could easily burn a hole in the can or melt something else..
Anyway I ve found some for cheap on Ali express if you want to experiment..
www.aliexpress.com/item/1005001632612770.html?src=google&src=google&albch=shopping&acnt=631-313-3945&isdl=y&slnk=&plac=&mtctp=&albbt=Google_7_shopping&aff_platform=google&aff_short_key=UneMJZVf&gclsrc=aw.ds&&albagn=888888&&ds_e_adid=&ds_e_matchtype=&ds_e_device=c&ds_e_network=x&ds_e_product_group_id=&ds_e_product_id=en1005001632612770&ds_e_product_merchant_id=107741654&ds_e_product_country=CA&ds_e_product_language=en&ds_e_product_channel=online&ds_e_product_store_id=&ds_url_v=2&albcp=19366866438&albag=&isSmbAutoCall=false&needSmbHouyi=false&gad_source=1&gbraid=0AAAAACbpRIm8o47laNthUFDvKWGzdbUxI&gclid=CjwKCAjwgfm3BhBeEiwAFfxrG4DBh2VYtsZTD6Uvx678yaPmL-yrw1COhgioQLFGbZnltLXU5Sah3xoCOm4QAvD_BwE