How Rocket Engine Fuel Injectors Work: Coaxial Swirlers

[@CopenhagenSuborbitals]

Thanks for watching! We are an all-volunteer, crowd-funded project, fueled entirely by your donations. Head over to www.copsub.com/support-us if you feel like being part of our one-of-a-kind mission! :)

[@RWBHere]

Thanks for the update. That's beautiful machine work! A couple of questions, some of which might be impossible to answer until the tests have been run: What temperatures will the swirlers and the mounting plate experience? Can the brass survive the temperature differential between the different tanks and the combustion chamber? Will they be able to withstand the high temperatures if anything fails to go according to plan, in the combustion chamber? Thanks again.

[@Turcian]

On one side there's SpaceX and RocketLab being super secretive about their engines. On the other side, there's Copenhagen Suborbitals showing pretty much every detail. Love it!

[@CopenhagenSuborbitals]

They have both legal and business reasons for that (ie ITAR). But you also have to give credit to SpaceX, RocketLab and many other new space companies for raising the bar in the commercial/government space industry when it comes to transparency. :)

[@Turcian]

@@CopenhagenSuborbitals That's also true. I appreciate you are reading and replying to comments. All the best!

[@tamasmihaly1]

Information is precious. I do not begrudge SpaceX for keeping things dark. Competition is war.

[@equation1321]

Well actually, SpaceX are not that secretive

[@waterlife.1905]

Group thinking is critical to being better than AI. If you got a few hundred people that are all involved in rocket engines to give free input...and there is a lot to gain listening to non rocket scientists, a different perspective and unexpected ideas.

[@lewismassie]

Nothing better than a quick and easy explanation of a concept, with some CAD and some examples

[@3DigitalCooks]

Top! Love Thomas vloggin about the new injector~~

[@steveeisenburger6011]

Super cool dudes. Saw you on SpaceX'nthnews, special mention. Interesting stuff boys. Keep it up, as I am sure you will

[@CopenhagenSuborbitals]

Thank you, Steve! Glad to have you on board. :) Lots of interesting stuff coming up.

[@j1j250]

this is so cool. i’ve been watching you guys for a couple years and it’s so great that you guys are finally actually working on the rocket that will finally complete your goal. :)

[@the_puzzle3412]

Awesome video, to watch in the coasting phase of Falcon Heavy!

[@RadekSzabla]

this insane . how precise should that be ! Hopefully Ill visit you someday that you will be able to show us live this engine !!

[@aquatone327]

How are the inputs connected to the injectors? ..Nevermind..pressure in the injector flange..got it got it. Very cool!

[@MechInvent]

In the next few months time I plan to print this setup in metal, all swirlers and plates included... no brazing.

[@catherineharris4746]

Simply outstanding!👍👍👍

[@sonofeloah]

Amazing! I had just watched a couple of days ago a DIY aluminum can alcohol stove where he had angled the exhaust holes to perform a swirling effect of the flames, thus producing a flaming vortex. Very crude but very effective use of the fuel. And here you are doing a much more high tech version that in effect does the same thing. I think you are onto something that will revolutionize rocketry!

[@jnielsen20]

Actually the idea of using swirlers in rocket engines have been had before, at least by the pros...

[@Jens.Krabbe]

@@jnielsen20 Even SpaceX new Raptor engine use swirlers: twitter.com/elonmusk/status/1132894389095653376?s=19 "Raptor uses a large number of coaxial swirl injectors, which (we believe) achieves highest theoretical mixing/combustion efficiency."

[@markhatch1267]

Wow! I finally get to see the real magic of how to build a rocket engine. Keep up the great content.

[@miguelarguelles2704]

Excellent work!

[@MortenEngelsmann]

You are doing a terrific job on Copenhagen Suborbitals. Your communication to the public is both educative and good investor relations practice. No doubts. I would kindly ask you to spend a bit of improvement effort on the sound quality, especially the sound / speak in the office chair part could be more distinct. Anyway - GRRREAT job.

[@CopenhagenSuborbitals]

Thank you, Morten! Audio is always a fine balance between getting the best sound and not having the microphone in frame. :) We'll try!

[@RoboticsClubTheRoboticsClubatG]

Thank you for sharing!

[@tamasmihaly1]

Thank you for the education! I love your channel. Fuel injection is quite fascinating under these extreme conditions. Amazing we humans can make the barely possible, commonplace.

[@willywgb]

Would there be any advantage having the cones spinning opposite to each other?

[@youtubeisapublisher6407]

They mention a few comments down that it could improve Fuel/Oxidizer mix due to the increased speed of propellant particle collisions, so it might. They probably have limited budget so trying both out might not be feasible however if I were them and I had budget to spare for such a thing I'd mock up two small scale model test bells one with the normal valves and one with a set of counter-rotating valves and see which one generates better results.

[@alexg3446]

When is the first test flight planned for Spica?

[@handsanitizermk.268]

Love to see progress.

[@telling25]

Hi, thx for the video. Maybe this is a stupid question, but why do you have the angular momentum in the same direction. Would it not give a better mix if the where opposite, resulting in having the fluid collide head on in the cones?

[@CopenhagenSuborbitals]

That's a good question and actually it's something we are trying out as well.

[@Kanerade]

How would you throttle with these injectors?

[@MegaM134]

that's exactly what I wanted to know !! perfect video ! thanks a lot for your explanations.

[@markayala7752]

love your project .

[@BillySugger1965]

Another outstanding development by CopSub! I was expecting the LOX and fuel to swirl in opposite directions for better mixing. Does this not work?

[@DamienPollet]

I wonder as well… maybe swirling in the same direction helps the mist diffuse, because when the cones collide they do not cancel their tangential velocities? 🤔

[@maxk4324]

@@DamienPollet usually in rocket engines there are 3 flow regions. Going from injector to nozzle, 1) injection where you want to break up propellants into as tiny droplets as possible, 2) the diffusion flame where most (~99%) of the combustion occurs, and 3) an acceleration region before the nozzle throat where the hot gasses have mostly finshed reacting and are being accelerated up to sonic velocity by the time they reach the throat. For injectors the goal is not usually diffusion but rather to break up the propellant into tiny droplets and to disperse those droplets as uniformly as possible. So in theory, a counter spinning swirl would improve propellant break up into tiny droplets, but I wonder if it would have a negative effect on the distribution uniformity (ie creating ox rich and fuel rich pockets later in the diffusion flame). Its pretty hard to say without running a full engine test or without some next level combustion flow simulation (ie stuff you'd run on supercomputers).

[@adrianleutner1918]

Hello @CopenhagenSuborbitals thank you for showing your Injectorplate + Injectors. Very Impressive! I am very curious because I can't see a sealing between the different chambers. Is the metal tightening enough? Or is there no Issue when methane gets in touch with the oxidiser prior to Injection?Or is possible to neglect the contamination? Best Greeting from a Munich Student Rocket Team

[@zyxwvutsrqponmlkh]

What are your thoughts on tomatoes, and 3d printed plastic rocket chambers?

[@montage1926]

[ ] How are the fuel are oxidizer feed into the swirler. Since you have 19 of the swirlers and 4 small ports on each of them, it looks like it'll be a challenge to get the fuel and oxidizer inside each of them. How will the piping work?

[@BaldurNorddahl]

Can some of that brazing be replaced by a heat shrink process instead?

[@CopenhagenSuborbitals]

The lids could probably shrinked in place. But the other seals have to be quite perfect to prevent mixing of LOX and fuel in places you dont want it to mix.

[@BaldurNorddahl]

@@CopenhagenSuborbitals I would expect the heat shrink process to produce airtight and strong couplings. In any case, no significant amounts of LOX and fuel will flow in the reverse direction due to differences in pressure.

[@maxk4324]

@@BaldurNorddahl A difference in pressure is exactly what would cause a leak, if the difference is high enough. Unless you're saying that the pressure difference is tiny, which I would contest by pointing out that the fuel will likely be at a much lower pressure since it first has to pass through the combustion chamber cooling jacket

[@BaldurNorddahl]

@@maxk4324 The point being that the pressure differences presses this thing together instead of blowing it apart. Any leaks can only go in the direction of the combustion chamber because that has the lowest pressure. The only seal is from the LOX to the fuel part of the swirler and even if some tiny amount of LOX go that way, it could never burn and it could not enter the fuel stream before the swirler.

[@wilsonmura5930]

It looks like a great job for 3D metal printing.

[@CopenhagenSuborbitals]

It certainly does! And there is a significant effort in the industry to 3D print this type of injectors, or basically any type of rocket engine injector. Sadly, it is prohibitly expensive for us. Moreover the surface firnish is not quite good enough yet from 3D printing. I will expect some variance between elements of this type if it was made with 3D print.

[@lancer2204]

@@CopenhagenSuborbitals This may be of interest, particularly the ability to transition between alloys on the fly kzbin.info/www/bejne/j3i0hKeYltZ0qLs

[@wilsonmura5930]

@@CopenhagenSuborbitals I agree it can be prohibitively expensive, out of curiosity what are the operation temperatures that the swirlers must handle?

[@maxk4324]

@@wilsonmura5930 probably pretty cold, given that their core is passing liquid oxygen. Their downstream face will get some IR heating from combustion, but the combustion reaction itself should take place at some distance downstream of the injector exits rather than right at the injection face. This is why injectors (usually) don't need cooling systems like the chamber, they pretty much are their own cooling system.

[@wilsonmura5930]

@@maxk4324 Oka so then, 3D printing it is not a crazy crazy idea?

[@jojoholly4875]

Why use brass? Is it for budgetary/manufacturability reasons or thermal transfer needs? If you had an unlimited budget, what material would you pick, and why? Maybe because the chamber would fail long before the injectors..?

[@carlosalbertovelascoquirog9957]

Excelente ...!!

[@Behemoth29]

How do you supply LOX and Fuel to the injector? What does your manifold look like?

[@justanotherasian4395]

Behemoth29 probably some small tubing

[@nikosalonen9671]

Question: I think I saw the holes to be directed to same tangent direction. What would happen if the directions would be opposite? Would atomization be better? I would assume the velocity would drop because part of the forces of the flows would be opposite direction, which would not be good for performance?

[@AIM54A]

An Induction heater would probably be great for brazing the individual injectors.

[@CopenhagenSuborbitals]

That could work well. We have an old ceramics oven on hand though, so we will give it a go in that one first :-)

[@davidrivas55]

Looks awesome! The part came out super good. What kind of mass flow rates will this injector see?

[@OldGamerNoob]

would having the fuel and oxidizers swirl in opposite directions be better or worse?

[@CopenhagenSuborbitals]

That is a really good question. We discussed it earlier but seems to have forgotten about it again. Intuitively the increased collision velocity (when moving opposite) should give better atomization. Perhaps we need to ask PH Spaanteknik for another shipment of test elements... :-)

[@OldGamerNoob]

@@CopenhagenSuborbitals oh, ok. I'm a recent subscriber so I'll go back and check videos I missed.

[@s.sradon9782]

Minor issue but I find the lip smacking very distracting. You can automatically cut that out with most audio processing software like audacity.

[@dhrumil979]

Are there any research papers for the design of this injector

[@Slime2112]

Why is brass used for the fuel injector? Other metals have a chemical reaction with the fuel/oxidizer? (Like steel has a higher melting point, lower mass, and higher strength) Am i missing something?

[@JakeBiddlecome]

One thing I've never been able to understand is how those huge tanks of fuel can be forced through those tiny injector holes. There has to be a limit to how much a liquid can be pressure fed through a hole that's just a couple mm in diameter. Even with a dozen injectors there's such a tiny feed it has to go through in just a couple minutes. Just how??

[@Shrouded_reaper]

800bar of pressure will do whatever you want lol

[@hellovikramjeet]

Are the holes in the side on the injector plate due to film cooling? Or do they have something to do with either of the biprop manifolds?

[@CopenhagenSuborbitals]

That is where the fuel comes through from the cooling jacket into the injector.

[@till2911]

Do you have any resources on how I can design my own?

[@jeanpecquet90]

Lovely !

[@pranavdesai5333]

The raptor engine also uses the coaxial swirlers

[@VortrexAerospace]

hi i am interested in buying a few injectors like yours, is it possible that i can buy them somehow? Thank you, good day :)

[@ATINKERER]

Why swirl the outer stream? The inner stream can swirl to fan out, and the outer stream can just go straight and intersect the fan of the inner stream.

[@omsingharjit]

What's pH bond ? Powdered cast !!

[@ShrirajGPethe]

I always considered that these two sections were swirling in reverse direction, Compared to each other.

[@mrveller3441]

Hvad er årsagen til at i bruger messing istedet for et lettere metal?

[@ravener96]

Is there a reason for the size selected? One would imagine a larger nozzle being easier to machine, and you need much fewer of them. Also, a test engine taking only a single nozzle would be interesting for a Vernier engine.

[@FrancescoCruciani-frx08]

cool! so the fuel flow goes directly from the regen cooling chamber to the swirlers? how is the fuel temp at this point, is it problematic?

[@CopenhagenSuborbitals]

It can be, that's why we have been running on 75% ethanol / 25% water mixture. Adding some water to the fuel lowers its boiling point. Then again, a year ago we've tested up to 92,5% ethanol / 7,5% water with a TEOS additive to the fuel, which deposits an insulating layer on the combustion chamber wall to reduce heat transfer to the regen cooling chamber, and the static tests ran with no issues at those mixtures. That's from this test: kzbin.info/www/bejne/oaC2oZ1np7KXj80

[@Philly_Willy]

not to intrude, but could you send the 3d model of this injector? (if its okay of course) I would like to make a rocket engine, and would like to test different types of injectors. Thanks in advance!

[@CopenhagenSuborbitals]

No, we are prohibited to export injector technology by law in Denmark.

[@berkely2577]

What alloy of brass are these made from?

[@CopenhagenSuborbitals]

Should be CW614N.

[@Jens.Krabbe]

@@CopenhagenSuborbitals www.holmedodsworth.com/materials/datasheets/brass-datasheets/cz121-cw614n-free-machining-brass Melting Point: 890 C

[@itsmesuryat7570]

Why brass though?

[@saimohitAeronautical]

Hi sir Iam a student who is working on the rocket injectors designing. Iam trying to get some existing rocket injectors catia/cad/solid works any design but failed to get them.can you please send me the rocket injectors design's. Please sir ,you are my only hope.

[@johnszott956]

Would heat or vibration have a effect on the integrity of the brazed joints?

[@maxk4324]

Since injectors will be passing liquid through them (one being a cryogenic liquod) whenever combustion is occurring heat should, ideally, not be as big an issue, unless some weird fluid dynamic phenomenon occurs that couldn't have been predicted. Vibration, however, is definitely something to keep an eye on. I wonder if they should make a mock up injector flange and then run a heavy duty vibration test to see if it wears out quickly.

[@jamescox7801]

*THICH*

[@jimbojets]

Paraffin wax mixed with carbon and aluminium powder hence colour.. Yep NASA I've been trying this combination as well.. For 6 years..

[@thelloyd87]

I really wanted to see how it works but I can’t get through the tongue clicking.

[@Demirci91]

4:32 listen carefully 🗣🙎

[@phillysauto4724]

IT SOUNDS LIKE YOU ARE IN A TUNNEL

[@hsathgfaaoe3547]

North Korea , Iran have entered the chat. Open source projects are of incredible value but we must not be naive

[@CopenhagenSuborbitals]

We are not really open source because of those reasons. We do share our developments, but when it comes to critical technologies like guidance or injectors, we don't share much more than you could find in a textbook on google.

[@hsathgfaaoe3547]

@@CopenhagenSuborbitals that's very reasonable

[@fbq8yg4k]

Cool but you need to learn how to animate your models. Saves a lot of discussion

[@corymitchell3228]

So pretty I could sleep with it

[@artgreninja3527]

Hue I’m fernch this is astronogeek qui m’a conseiller de vous this KZbin Channel After astronogeek this is in french

[@baseder514]

every smack you make with your mouth after every sentence is getting rather annoying =) stop it please.