Why rocket engine valves are difficult. Specifically the liquid oxygen ones.
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- เผยแพร่เมื่อ 25 มิ.ย. 2024
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In today’s video, we will talk about the culprit of so many hard starts, failed starts, off-nominal mixture ratios, as well as rocket and spacecraft delays universally - propellant valves. And we will try to answer whether our home-built liquid oxygen valve prototype for our upcoming 100kN ethalox rocket engine can actually do its job under all the cryogenic pressure.
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Intro and Outro Music by Everyday Astronaut:
www.everydayastronaut.com
TIMESTAMPS:
00:00 - Intro
00:44 - Valve Assembly Break-down
01:46 - Challenges with Operating Cryogenic Valves
04:29 - Testing our BPM-100 Rocket Engine Valve with Liquid Oxygen
05:08 - Test Results: Real Life Out-performing the Simulation?
06:44 - Solenoid vs. Ball Valves
07:24 - The First BPM-100 Engine Combustion Chamber Parts!
08:03 - You Can Help Support the Spica Rocket!
08:44 - Outro - วิทยาศาสตร์และเทคโนโลยี
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So how exactly do you deal with the differential thermal expansion? It still seems like the label would either leak or seize when exposed to liquid propellants.
I like the term "unscheduled rapid disassembly", I'm going to start using that at work.
@@favesongslist Actually... This is NASA's term for a crash. URD
Elon first used it😂
@@ankitnmnaik229 nope
Cool how Tim Dodd's music is being used by a real rocket company!
Also, love these videos, really cool!
We are just a group of volunteers doing this in our spare time, so not a "real rocket company", but the grown-ups at Rocket Lab do use Tim's music during their launch live streams! ;)
@@CopenhagenSuborbitals Grown ups at Rocketlab, haa! If weather is well, they'll be recovering their first stage for the first time today!!
Copenhagen Suborbitals seems like a cool place to be at!
@@CopenhagenSuborbitals there is a pointy end, a flamey end and it does rocket things. You guys definitely play in the same league as the Big boys.
Starship’s pressurization valve froze on April 17th, 2023.
Been watching for some time. Best of luck to you all!
Yes, this is very true - proceed with caution. I worked at a startup hybrid (polybutadiene+carbon and LOx) rocket company in the 1980's (left when the president passed away). The company was sold. The new company attempted a launch. We used cryo-ball valves, and due to the hybrid nature, it required 25% open of the LOx valve for ~10% throttle to establish a grain in the propellent. Well, it was commanded to go to 100% and the ball-valve shaft failed. Vehicle was clamped down but could not be released and could not shutoff the LOx due to no valve control. Ooops.
This video aged so damn well. Starship 4/17 test flight was scrubbed for same reason.
Unlike Pythom, you clearly are doing the job right. Keep up the awesome work!
Great video and I love the fact that you are using "Moon Dance" from Tim Dodd.
How long until you guys expect the BPM-100 will be ready for the test stand? I'm looking forward to see it in action
Hopefully before the end of this year, but I'll need to check with the booster team whether that has changed. But there are lots of variables, for example our new high-speed spindle on the CNC mill just broke after finishing the second combustion chamber part and now we'll have to wait for a replacement from the manufacturer.
I love these types of updates, the small intricate pieces that make up rockets internal systems is super interesting. Keep up the good work 🤘
The way he's touching his "baby" ;). Proud engineer, and rightfully so :). Well done.
Rocket assembly seems to be in a good way ! You're amazing !
Fantastic progress. Good luck to you all :)
Brilliant. Well done!
Congratulations, Adam!
Man this is cool stuff!
Throttling with a ball valve is very difficult. Awesome video!
This video was ahead of it's time wiht the starship launch attempt
This, I need more of these types of videos! Not many out there that can go into the deep, inner working's of a rocket. Shhhh don't tell ITAR!
Really cool stuff!
Awesome development! Keep up the great work. You guys are an inspiration. I have always dreamed, since watching Neil Armstrong walk on the moon on TV, about joining up with a bunch of guys and building our own space ship!
One of many, many, many reasons why space travel will never be cheap.
Adam Kiss is the PERFECT name for a mechanical engineer!
Good job guys! Denmark is fore sure leading but we should have a race to first Nordic rocket to orbit. As a Finn, I think my Perkele 1 rocket will use Koskenkorva as a fuel. I'll probably need a good 500kg to orbit capabilities as a I need to get my sauna to orbit as soon as possible.
TH-cam algorithm did a half decent job this time, nice work guys.
Thanks for a fascinating discussion!
One quibble: Many of us who watch this sort of thing know what rock music sounds like, but we do not know, or equally enjoy, the sounds made by the equipment and processes being demonstrated.
If you want to know what real rock music sounds like... go to Finland... they have a lot of Hard Rock laying around like everywhere. In Helsinki they even have a Hard Rock church... A church that was digged into a HARD rock... and also on the bus and in the restaurant you will hear DM at daylight... to impress the chicks... get a good wig...
@@Heisenberg2097 That...kinda misses my point. I don't want to hear rock, Finn or not. I want to hear motors, valves, and fluids.
@@50srefugee Try MOTÖRHEAD... louder than the average Lamborghini I see here on the streets in my lovely village so many times... esp. at sunny days they come to burn money for no reason but show-off... they are also very good at parking badly... and the chicks in there are high as a kite...
@@Heisenberg2097 [facepalm]Pretty sure you are trolling, but one last try: MOTÖRHEAD may be loud, yes--but utterly the WRONG sort of noise for an engineering video.
@@50srefugee Ok. So the loudest I have seen and that is maybe more your taste was a MIG-29 going straight upwards in the sky. Turning of the turbine... starting it again. That was the IFA 2005. Very impressive.
Works thats good.
This was recommended after the starship launch which was delayed because of a valve.
thanks.
Here after Starship scrub
You could try making it a "trunnion" ball so that the actuation force is more consistent.
So, the pneumatic servo is probably better. It provides very high torque and very high speed. Also it is not true that pneumatic system can be only 1 or 0. There exist electro-pneumatic positioners. One of the best are manufactured by Siemens. Those uses piezzo valves.
Very informative video, thanks! I see you are using a relatively small brushless outrunner motor (around 40x50?) and probably a Vesc based esc. Can you tell what voltage you use and how many amps is your setup pulling? What kind of torque do you require to open the valve in the working condition? Thanks!
Did you ever figure out why the simulation underestimated the valve speed? I'm no engineer but I feel like that would be an important thing to do as it clearly didn't take something into account, and that something could affect the system as a whole outside of the testing environment.
As Adam mentioned in another comment:
"If you work with COTS components it is really difficult to get high precision and extensive engineering data on many parameters. These parameters are all part of the eventual valve model. You are left with the options of either measuring these parameters yourself, exploding the workload or you can guess your way through it supported with some measurements, resulting in less workload but decreasing accuracy. "Optimized components" and fancy motors with exotic magnets are the privileges of companies having a lot of money for R&D. If you are a crowd-funded volunteer organization, you make do with what you have money and time for. ;)"
Salam sahabat dari Indonesia 🇮🇩🇮🇩
Excellent video! Very informative. Why do you use motor actuation instead of pneumatic?
If I had to take a guess, I would assume because it is lighter and much less complex than a pneumatic system. Kind of like how Rocket Lab and Astra use battery driven pumps in their engines.
@@dr4d1s That along the right avenue of thinking. We already have enough electrical power on board for electrical valves, but starting on a pneumatic system comes with large weight penalties for the piping and the pressure vessels.
My Chevrolet Matiz 2005 also has difficult valves, the return valve in steering lubricating and brakes, air blocks pedal and is released with hissing sound and pressing gas, jaults and fluctuates rpm
Is this in my recommendations because of the Starship frozen valve problem?
Cool
Great job! For such propellants flowrate and pressures level why not the simple pneumatic valves for both Fu and LOX lines with the throttle in Fu line for propellants mixture ratio control or throttles in Fu and LOX lines, if you need to change engine mode during the flight also?
Probably the weight (mass) of 3" diameter pneumatic valves. However a slower rotation speed with a less powerful motor might be good enough for some valves in the rocket, saving further weight.
Pneumatic systems come with a weight and complexity penalty.
When will you guys will make the space capsule
Man
Hopefully once the current recruits finish building their rocket (most of the hardware for their rocket is done), some of them can start helping with the space capsule production.
What is your istemates
Regarding to space capsul
Means when will you send it in space
Reply please
Interesting video. I was wondering why you choose a ball valve versus a gate valve?
Ball valves a faster and seal better. They can also handle higher pressure when throttling high pressure flow. Gate valves like to be open or closed. They don’t like to be under pressure in some intermediate state. But that might be the heuristic for repeated duty cycles. I don’t know if this would necessarily be true for a single use rocket engine.
Krytox works well as a ball lubricant in LOX environments.
Keep the ball moving, even when the valve is closed so it will not freeze.
Hey, how did you figure out how much torque the ball valve would require to open and close?
How about lots of dimples to reduce the friction? Also the center could be drilled with lots of through holes instead of one large hole. Then the whole surface wold be uniform density.
Hi, just one question is it possible to use a proportional hydraulic valve and rebuild it to work with cryogenic oxygen for smaller rockets?
How important such small parts can be
Why does the ball have a round opening on one side, but a baseball-diamond shaped opening on the other?
Nice music choice lol
Liquid oxygen is typically used for the energy derived by the large conversion value of liquid to vapor in conjunction with a secondary vapor fuel - the oxygen liquid vapor kicks in as the rocket gains altitude . The liquid to vapor conversation occurs through a by pass line through a turbo pump. You also have to be aware of "POGO" if you don't manage fuel flow - just an opinion I'm sure you have evaluated. Good luck.
Interesting stuff
Q: Rather than venting to the atmosphere the oxygen stuck in the ball valve cavity when closed, why not have an extra (small) hole in the ball between the cavity and the tank side? Advantages would be less plumbing, no vent (which can become blocked with ice) and no lost oxygen. May affect tank pressure tho
My guess is that it would work but it also would be way harder to seal since ball valves usually have two seals, one on the tank side and one on the outlet side, with this technique you loose the tank seal...
Imagine working on something for 12 months and then it's there and just working
you are effectively building a V-2 from scratch, that's amazing
How did you get the backlash out of those Dynatorque gear operators?
What ball valve is being used?
how is the shrinkage calculated?
Try butterfly valve
Do you test with LN2 first for cost and safety reasons, or do you go straight to LOX?
It depends. This time we had some leftover LOX from a recent engine test, so we went with that.
Why you do not have a stem for a cryogenic valve?
Sure it's good news that the performance of the valve in practise was better than predicted rather than worse. But maybe that raises questions about the simulation models you have been using? Ideally the test results should match the predictions.
I was wondering about this as well.
It could easily be due to safety margins in the simulation that was broken in the test, I imagine. It should be possible to beat the standard model if you do proper repeated testing, and you ensure that all components are optimized properly.
You have to push the limits if you want to go far when fighting gravity.
@ @gijbuis, If you work with COTS components it is really difficult to get high precision and extensive engineering data on many parameters. These parameters are all part of the eventual valve model. You are left with the options of either measuring these parameters yourself, exploding the workload or you can guess your way through it supported with *some* measurements, resulting in less workload but decreasing accuracy. "Optimized components" and fancy motors with exotic magnets are the priviliges of companies having a lot of money for R&D. If you are a crowd funded volunteer organization, you make do with what you have money and time for. ;)
@@Datamanna I wasn't talking about optimizing the individual parts, but optimizing the rest of the rocket for the parts that they have. Tuning things according to actual performance.
Of course trial and error is needed with complex systems like this, regardless of the budget. "Proper optimization" depends on the parts you've got, and those parts aren't all that accurate at this level. You have to establish what "optimized" means yourself, in terms of the entire rocket.
Interesting to see an actual cryogenic valve. I suppose that similar valves are used for regulating the flow of liquid methane/LNG as fuel? Or do these have different requirements?
We use "room temperature" ethanol as fuel. But valves for it will be similar.
@@CopenhagenSuborbitals it's my understanding that using liquid oxygen and LNG is making things more uniform in managing the fuel/oxidizer tanks (similar temperatures etc, so less difference in expansion etc)
@@alcosound
Ethanol are not at all comparable to LNG!
We use LOX at 183 degrees and ETH at 12-17 degrees "ccc" (Civilized Celciated Centigrades ... C for short ;-))
So when you reach space, are you going to change your name to Copenhagen Orbitals?
Funny! Thank you ;-)
Lots of gearboxes for a valve. Those hobby motors can be rewound to increase torque.
Does this valve have DPE (double piston) seats? Thats the best way to vent excess pressure thats captured in the ball area. Also Id put a pressure relief valve where you beed to vent.
Ultra fast actuated valves are usually air/oil actuators so this is impressive to use an electric motor.
Also how do you avoid the actuator from freezing? That cast iron gearbox isnt rated for the cold temps.
I guess they tend to choke under pressure.
Is it going to be subjected to temperatures above 80C?
If so you need to be careful about the neodimium magnets in your motor drive.
You may want to use cobalt samarium magnets, just in case.
It has liquid oxygen running through it. I don't think heat is going to be a big problem.
@@stargazer7644 the motor is located quite far from the oxygen tank. There may be the engine right behind.
@@makerbeelab5546 Quite far? It's directly connected by a metal gear box and mounting flange to -183C. We call that a heat sink. The hot part of the engine will be (by definition) downstream of this valve toward the combustion chamber.
@@makerbeelab5546 Distance to the tank doesn't matter. The oxygen has to stay liquid until it leaves the injector to ensure a constant flow rate, so the valve itself is guaranteed to be very cold. I have a hard time seeing how convection would overcome the conduction at this low temperatures, at the very least if any kind of thermal protection is applied.
In other words, I wouldn't expect the valve to be the first thing to fail if temperatures went high, and I know that they will test things.
Why don’t the valves have warmers?
the raw metal materials for building cryogenic mechanics should be kept in low temperature for one month or more before machining. After internal stress fully released in low temperature, dimensions are much more repeatable / precise.
Wow. Okay. I know this is a prototype. But I still wonder, if this amount of kit actually needs to go to "space". If I guess rocket-science correctly, you would open the valve once and then be done with it? At least for stage 1. (Or do you need to close it for staging?) So could the drive moved to stage 0? Have a long stick poking out of the rocket which can be turned to open and close the valve. Motors and gears stay at the launchpad.
Very informative never realized all these challenges are involved! Are there no of the shelf valves for rockets? Is this like a proprietary thing? And a remark from one creator to the next: the background music IMHO really does not fit your great vibe. Use a bit more mellow space theme instead of this I would suggest.
Hans Zimmer didn't answer the call ...
same as spacex
Going to be honest 12 months to design this is insane.
At SpaceX we redesigned ours in a month
A "better part of a year" does not necessarily mean 12 months. But either way, we wouldn't expect a Master's student at an organization with a yearly budget that matches SX's monthly coffee expenses outpace you guys and gals. :)
Thank you for new video. consider in use titanium valve? have les expansion when temperature change.
Titanium is expensive to gather work with, and if it isn't needed then it's pointless.
An amateur project like this with limited budget has to focus on "good enough" in order to have a chance to make it to the finish line, or the support goes away before you have enough money to show things.
Edit: Besides, I'm sure that an unscheduled rapid disassembly could make way for a lot of interesting content.
I would personally be rather pleased with a failure like that. I'm pretty confident that it would even help the project reach the finish line faster, if it gets covered or retold properly. There is a lot of interesting thoughts that go into the analysis of the remains and the following problem solving.
I think you might have missed the "low cost" and "off the shelf" requirements.
🥶
Do you guys have a goal set for a launch? Either way pretty sure there is no quit in CS and you'll make it....new MACH3 member and want to see my name on your rocket
Quite a bit of assembly and testing remaining to go smoothly to place our bets on a launch date. :) Thank you for the support, it means a lot!
@@CopenhagenSuborbitals as long as it's in my lifetime!
Why didn't you go with a globe or axial valve?
When you get to get to putting things into orbit can you put a ham radio satellite into orbit?
I follow your progress now for quite a while and i am impressed. But there is one question i still have about your operation. Why don't you use additional booster rockets for the initial start? They are cheap, way easier to build and add a lot to the innitial thrust. So were am i wrong with this?
Simple answer is because we don't need it. We believe we can make a liquid engine powerful enough for the task. Adding secondary propulsion systems increases costs, schedules, complexity, and risk.
😎🤘
5:58 Requirement: 1s
Design simulation: 1.6s
Oh well, let's build it anyway!
Well if you don't know how to meet the 1s within reason (economics), building a test setup getting close to requirements to test the theory and gain understanding, is an acceptable engineering approach. That way you can acquire the knowledge required for first principles development and with experience and knowledge gained, redesign a solution to meet technical and economical requirements. Sometimes you have to learn to crawl before you can walk let alone winning a 100m race.
Much more impressive than the rich SpaceX that delays flights all the time
Adam Kiss is a Hungarian?
And you’ve decided/committed here to not use pneumatic/fluid power, right?
Yes. Less complexity and added mass.
@@CopenhagenSuborbitals Do you mean that the electric system may be heavier, but also easier to actually finish?
Hello I have a question , how do you prevent over pressurisation inside the ball when the liquid oxygen evaporates . This ia really a challenge considering use of normal valves for cryogenic application . Also y not use solenoid valves .....I think answer to this is magnetization in cryogenic condition . Magnets if subjected to cryogenic temperature will behave differently and there will be no control over the valves .....let me know if I m correct . Also please do answer the liquid oxygen boil off question .
Watch to the end, although they didn't detail their method of venting the ball.
@@johndododoe1411 watched the full video still unclear ....I don't think they mentioned their secret 😜
@@thecros1076 Near the end they talked about both subjects, but didn't reveal how they avoided boil off inside closed valves.
I am not sure because I haven't seen it, but my guess is that they drill a hole on the side of the ball valve casing to make the ball's hole align with it in the closed position, but remain sealed when LOX is flowing through it. In terms of the solenoid, they want throttle control so a solenoid won't work for regulating the flow of LOX. Also the only change the solenoid would experience is an increase in magnetic force under cryo temperatures which would actually benefit it. I hope that answers your question :D
@@backyarddynamics7297 great answer bro , I thought of the same vent hole mechanism .
Really no one is forcing you to use liquid oxygen --- there are so many other kinds of oxidizers around (not counting those which can be burned in a hybrid motor with aluminium and other metals) ---- however Copenhagen Suborbitals decided to use the original V2 fuels
... I know that music...
Yeah, when I get back in about 10 minutes
Liquid Oxygen is warm. Liquid Hydrogen is -253 C!
stainless steel valve
I hear you talking about THE valve. How about redundancy? Specially when human lives and lots of money are involved?
Exactly how do you expect redundancy on a valve? Redundancy on a valve means running another pipe. Realistically, if you're doing that you might as well just have another engine, which is why rockets like Falcon 9 just have a lot of engines and can tolerate engine failures.
Liquid or supercritical?
Wiley E Coyote technology at its finest 🤪
So German start to build their own cryo engine in stead of depend on French rocket engine.
Hello
hi
You should wear eye protection ...
If it is so difficult then how can SpaceX get it right every time?
Except for the times they didn't get it right? :)
@@CopenhagenSuborbitals I think they got the valves working without an issue - and if the did have an issue - it was quickly fixed. If you are saying that others have had a a many problems with valves as the SLS system… then you are wrong.
@@mullholand Valves causes all kind of problems in the rocket industry. Over the last two years we have had Starliner launch cancelled with valve problems, Dragon capsule blowing up caused by valve problems, Astra rocket a Kodiak failed due to valve and other issues, ISRO rocket failed in august 2021 due to valves. The list goes on and on. In that light, are you still convinced other have no problem with valves or are you just not enlighten about such issues? I mean "I think they got the valves working without an issue". C'mon Dragon blew up. I would have an issue with that.
@@petermaersk-moller3014 So how many have "blown up" since then? None. And it sure didn't take a year to fix it. Come on man - don't believe your own BS.... SpaceX has lighting quick reflexes. Something breaks - they fix it - and have HUMANS going up to space every few months. SLS... not so much.
@@petermaersk-moller3014 Dragon only blew up during stress testing, that's kind of the whole point to find these corner case issues. It's not like Starliner that made it all the way out to a test flight before they discovered the problem.
Using pyrotechnics actuator will greatly reduce the overall weight and aggregate components
Dont tell me you use the imperial(istic) system ?!? That would be ... not that clever lol.
We don't, but a lot of our viewers do, so we help them with the translation. :)
@@CopenhagenSuborbitals better help them to switch to the metric system 😁 And by now everyone knows that the rockets are metric 😉
So much of the time I wish even one space company/corporation would give out internships or even jobs to people under 18. Well this just means I have to build it myself. I will be the first amateur rocket engineer to send a spacecraft to another celestial body and the first person and amateur to return a sample from a planet.