Comparing Turbine Rotors

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NOTE: There's an error in the graphs where i label 20.1W as the max power on a data point below 20W. This was because i accidently clipped the Y-axis at 20W, but the maximum power was in fact 20.1W
This is the second part of my video on building a 3d printed compressed air turbine, which you can find here:
• 3d Printed Compressed ...
In this video I'll be experimenting to find the best rotor and casing geometry for a 2D-flow turbine. I'm focusing on 2D flow because of the relative ease of machining parts, since I eventually plan to build one of these out of aluminum or brass to power with steam.
All the tests are conducted at 50 PSI with a 1/16" nozzle.
Another goal of this project is to see if it's feasible to use a 3d-printed turbine for Brayton cycle refrigeration (like the ACM on an airliner does). This requires extracting energy from the compressed air in the form of mechanical work to drop its temperature, so a more efficient turbine will have more cooling power (and provide more mechanical output to drive auxiliary devices like a secondary compressor).
Overall, my best configuration achieved a ~20% improvement over my last video, but there's a relatively large amount of scatter in my data, probably due to vibration and temperature dependance. Some further improvements I still haven't looked at are:
-Tighter tolerances between the turbine rotor and casing
-A convergent/divergent nozzle to convert more of the pressure energy to kinetic energy
-Better seals to prevent pressure leakage between stages (or to the outside).
Music Used:
Kevin MacLeod - Groove Groove

Опубликовано:

26 апр 2022

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Комментарии : 186

@htomerif Год назад

One of the things million dollar, multistage gas turbines have in common is that each stage has a different geometry. I think maybe when you put a lot of back pressure on one stage and reduced pressure on the next stage, you alter their power bands so severely that they're actually fighting each other through the whole range of flow. (i.e. one or the other isn't acting as a turbine at all, but a really bad impeller) It might be interesting to artificially restrict the output flow on a single stage turbine to see how that affects the power curve. I know you've moved on to the pulse tube cooler and that does seem more promising for LOX/LN2 production, but these turbines are interesting too.

@nigelwilliams7920 Год назад

Agree. Look at the old double and triple expansion steam engines. The piston diameter and ducting increases with each stage. So with this setup the second and subsequent turbines and ducting should all be larger by the 1.6 ratio. The design seems to be struggling between being a pelton wheel (where the energy is transferred from the inflow by the change in momentum of the inflow water stream reversing as it hits the wheel) and an expansion engine. The turbine stages are for expansion, and should be sized accordingly. All the present 'cog' design does is carry pockets of air at constant pressure around the wheel. The intermediate pockets do no work at all. The only pressure differential in each stage is between the first pocket at the inlet and last pocket by the outlet - so 90 degrees or 180 degrees to the exit may not make any difference. The ostensible purpose of a longer rotation to the exit is simply to reduce the air losses around the cog's sides by increasing the area of surface friction in the gap between the cog and the casing. May as well try a Telsa turbine in that case. Good luck with that!

@htomerif Год назад

@@nigelwilliams7920 Well, and with a steam locomotive you have the advantages of it genuinely being a positive displacement pump and being relatively slow. Even if you didn't make the cylinders larger and the ducting wider, you probably at least wouldn't get something *worse* than the power and torque you would have with the first cylinder by itself. With an expansion turbine (which this is kind of in halfway between land) you can have one turbine that wants to go at 10k rpm and another that wants to go at 8k, and because they're not positive displacement and you're doubling (like you said) ALL of the drag and fluid shear surface areas, the 8k turbine might actually being powered by the 10k turbing and you'll get 9k total (or whatever). I need to watch his first video, but I think he might have wanted to go with something like a turbocharger turbine vane design with an axial inlet and radial outlet. I think this design does choke off the ability for expansion to do work. There were a few wheel designs we didn't see in this video that looked like simplifications of a pelton wheel. I'm assuming they did worse or he'd be using them. It would probably be hard to print an actual pelton wheel and not have it self-destruct at the rpms he wants though.

@htomerif Год назад

@@nigelwilliams7920 I went back and watched his other video. His first video was an impulse turbine (basically half a stage of what you'd find in an axial flow gas turbine). It was ultimately less efficient than the 2d scoop things he used, but I think if he'd had a series of flow bending rotors and stators, the impulse turbine may have been much more applicable to multiple stages. He also has what looks to be several meters of 1/4 inch copper tubing to act as a cooler for the compressed air. I know from working in a shop that small diameter air hoses (like the plastic springy coil ones) totally destroy airflow. I have to wonder how much of the 50psi he's actually getting at the nozzle. Its fine for airing up a tire, but an air drill or impact wrench would probably barely work with that copper pipe in the path. (if you're reading these comments, just try breathing through it. You'll be surprised just how much resistance something like 10 feet of 1/4 inch pipe has)

@nigelwilliams7920 Год назад

@@htomerif Yes he would be better off using a turbo heat exchanger as the cooler as it has ample flow capacity, or at least several 1/4" pipes in parallel.

@nigelwilliams7920 Год назад

@@htomerif Indeed. Matching the design of each subsequent stage to the gas flow is a hard part of overall multi-stage expansion designs, otherwise you get back pressure/compressor stall etc. Frank Whittle no doubt went through this agony using the radial then axial compressor and the axial multi-stage turbine. Its a fun intellectual exercise for the tinkerer, but as they say 'Space (and aeronautics generally) is Hard'!!

@ironbunky Год назад

the fact that you use a song/songs that i've heard numerous times when building stuff in KSP makes your videos even better

@unusualfabrication9937 2 года назад

very cool! I think at 8:36, the tube there being kinked means that no air can flow between stages, causing added resistance with no benefit, which may be the reason for the efficiency / power loss.

@LuxGamer16 2 года назад

I didnt even see that. Good catch!

@LUSKAWITT_Apocalipse19_em_2O24 Год назад

I was thinking of doing the same thing about turbines and their settings for a compressed air engine. And you show me your video with so much detail and incredible video editing. You saved me a lot of money. Thanks.

@FPVtrix Год назад

Thank you for covering this project so thoroughly. It has reignited my interest in learning about turbine application for mechanical designing

@TalbotNC 2 года назад

One interesting thing to not is that all of these designs seems to be of impulse type. Meaning the pressure is being converted into velocity in the nozzle and the turbine simply redirect the already expanded gas. Not that its bad or anything. I just wanted to point that out since its a different beast than reaction turbines, where the gas continue to expand in the turbine. Keeping in mind this fact brings to light the fact that the nozzle where the air is accelerated is part of the design system if not as important as the turbine itself.

@TalbotNC 2 года назад

Also, I can't help but notice that all these new designs are just 2D profiles spinning around. Beware that these geometry causes your exit gas to still have a very high angular momentum a.k.a energy left on the table. Might I suggest experimenting with 2 additionnal parameters to try and make up for this : 1. Add an helix angle to a scoop design (like an helical gear) to straighten up the exit vector. It could be progressive, like first half staright then it helixes. 2. Or, reduce the radius of the turbine on the side where the gas is exiting. That way the spiraling down of the gas into a smaller radius naturrally imparts its momentum to the turbine wheel and the tangential component of the output vector gets minimized. This is literraly how a radial turbine works now that I think about it. Yeah, just do a radial tubine basically XD. They just work really great and aren't as finicky to tune perfectly as axial turbines.

@Graveyardham 2 года назад

Really cool project, your videos are so well made, offer great visuals and knowlage. Thank you!

@gammaleader96 2 года назад

Thanks for the update. This one got me even more interested, since I also always looked for a way to make an air liquifier. In Europe, it is even more impossible to find a sterling cooler for anything remotely close to a reasonable price. I'm looking forward to what you come up with.

@goma2809 Год назад

Great video! Thanks for sharing you research and test results.

@joshi2438 2 года назад

Your Videos are amazing i was looking for this kind of content just engineering and optimating while explaining the whole thing very understandable but on such a high level

@ivprojects8143 2 года назад

Very nice experiments! Thanks for posting.

@TobiDeMonkey Год назад

Fascinating man. Keep up the work.

@nefariousyawn 2 года назад

Looking forward to the next installment

@gotbread2 2 года назад

That last part with the Brayton cycle sounds very interesting. I also looked into that cycle, but more to use it as a heat pump / heat engine alternative to a stirling cycle, to use as a bidirectional heat storage system.

@officialdiadonacs Год назад

I would love to see you test out a Tesla Turbine in Part 3. Glad to have found your channel. You do great work 😊❤️

@spark_EE 2 года назад

When adding a second stage to your turbine, would it be more efficient to use less blades on the primary stage? Then it may allow more airflow into the second stage thus more power.

@xmysef4920 Год назад

Maybe also slightly bigger diameter on the later stage?

@charadremur333 Год назад

@@xmysef4920 actually a smaller ènt stage

@xmysef4920 Год назад

@@charadremur333 A smaller entry stage? Well that’s essentially just the same thing. Either you make the later bigger, or the one before smaller

@CroGaucho Год назад

@@xmysef4920 longer, so he can save some printer time and reuse the bigger rotor he printed earlier, while keeping nice design :)

@lynes2peters438 2 года назад

Awesome Project!

@rodriguezfranco3839 2 года назад

Catia ,rc boats , cnc 3d print thang this channel have it all , just suscribed 💪👍

@BloodyMobile Год назад

"0% efficient" xD 6:09 ohhhh, now I finally understand why those turbine stacks always look the way they do. I was wondering about that already, and now it clicked, thanks to the explaination and correlation.

@Androidzombie1 Год назад

THIS IS MY NEW FAVORITE RU-vid CHANNEL

@Relou4e Год назад

I just watched both videos and liked the project. As with engeneering background I would like to suggest improvements. - balancing the rotors: do it like the RCcommunity does it: 2 cones on a horizontal steel axis on two horizontal rails. - how about a pelton turbine? Maybe one-sided blades? You could add more conventional stages by making the outlet in a spiral way. More nozzles? - reducing vibrations by using only prime numbers like they do in the industrial designs - reduce friction by making spiral grooves on the sides of the rotor Good luck!

@chemicalvamp Год назад

I just found this channel, Thanks for edutaining me!

@68HC060 2 года назад

Excellent video. I'd like to see comparisons to ... 1: Results from smaller radii ... 2: A pelton turbine .. using the same housing you've already got.

@tylerhusky4065 2 года назад

Awesome build brotha!

@mcrotbot 2 года назад

awesome vid rally enjoyed it!

@curiousviewer5991 2 года назад

You're getting close to 10,000 subscribers! I've always liked how you do your projects so it's rather neat to see your audience grow to this point!

@phreeesubz Год назад

*They have over 80K subscribers*

@curiousviewer5991 Год назад

@@phreeesubz Yep. Lots have joined in the last 8 months.

@Bianchi77 Год назад

Nice video, thank you for sharing it with us :)

@chris993361 Год назад

I am pretty sure your air velocity would be slower in the second stage. So you probably need the second stage to either be on its own shaft or a smaller diameter to make up for the lower flow rate so it doesn't create drag on the first stage. And yes I know this is an older video now but I wouldn't mind seeing more turbine stuff.

@eduardotijerina958 Год назад

really good video, thanks a lot

@Tristoo 2 года назад

I just learned one can get argon from fractional distillation of liquid air. That's super sick and now I can't wait for the cryo stuff.

@nehabkeinyoutubesry Год назад

youre the kind of person i would focus on a party and sink into an hour long discussion about "why you cant shoot a potato above Mach 3" xD

@ernie5229 4 месяца назад

"I guess real life is more complicated than theory." You FINALLY learned something!!!

@nezihmertbolgul3605 2 года назад

Hello, FDM prints are not air-tight and you are using with very high pressure. It might be causing the pressure on the blades to decrease very fastly since you must be losing pressure on the chasis walls. If you can buy a SLA printer you can rule out pressure leak problem and have a lot better accuracy on your prints. I might not imagined this correctly but lets say you put screws on the both walls and sealed them with o-rings. it might help you gain the heat while you are decreasing pressure on the blades. As far as I remember, the formula you are using is used for closed systems such as piston systems. However, you have kinetic energy at the outlet. I might be wrong wanted to remind it :). I also wanted to experiment on the turbines but did not have enough courage to spin them that fast :). Very nice videos, thank you.

@rodjownsu Год назад

This whole video, I was thinking hmm, being able to create a mostly 3d printed turbine could be used for air liquification! As I'd previously also delved down this path previously, ended up attempting a Hampson linde instead similar to Tesla500 on RU-vid, he has since created the chronos high speed camera and air liquification is probably the last thing on his mind these days hah. I see you ended up going with the pulse generator later down the track which seems to be going much better!

@theecstatic9686 2 года назад

Dude please keep up with this...

@trailblazingfive Год назад

Great content; love the way you go thru subsequent iterations; the CAD software you were using for the modeling of parts was FreeCAD?

@twd892 Год назад

One major trick to compressor / gas pump efficiency is tolerances, like thousands kinda tolerances... The tighter your tolerances, the lower the losses to leakage around the turbine (within the casing), downside being cooling coefficient, compressing gas creates heat which you have to dissipate to avoid lock up under general usage conditions

@martingrobler1892 Год назад

My friend. I had a similar problem with a hydraulic motor that I wanted to build. On my design I found that when I placed the rotor in the center I had to deal with the negative force of the rotor. I do hope you would look at a much closer or almost sealing rotor-casing entrance and a expanding casing with a much larger exit. Hope this can solve your problem. Great presentation thanks.

@QuinceDeMayo-jg5wb 10 месяцев назад

Buen trabajo excelente explicación! Gracias Quizás si puedes unir los escapes de las turbinas consigas más W?

@MarinusMakesStuff Год назад

I think the issue with the wider rotor is the increase in mass. I would try out a slimmer rotor to see what happens. The power probably goes down a bit, but I expect the RPM to go up. This way you could use multiple stages with slimmer rotors to keep the RPM and boost the power.

@thomaskrieger5431 2 года назад

Hey nice work, have you tried a pelton wheel as a turbine. and probably have a look at the nozzle on the input size how the air is put into the case the angel and nozzle type seems to have a factor here. more seen in other videos than own experience but could help

@LordEgra Год назад

If you could polish internal side of blade notches, it could make air to escape with less resistance and thus increase the speed.

@wtechboy18 Год назад

I think part of your problem with the multi-stage setup is that your turbine blades are designed such that the high-pressure air is just instantly captured and halted relative to the turbine, as opposed to being deflected and expanded via an airfoil like a gas turbine normally uses. I think you should try designing some "normal" looking turbines in a snail housing just like car turbos use. That's more in line with how the turbopumps in i.e. rocket engines work anyways, or they use annular combustion chambers pointed through a jet-engine-looking turbine. The annular design might be easy enough to 3d print.

@Chris-go2iz Год назад

I've never seen any of your videos before, and now I'm hooked. I love your tests and step by step isolation of different elements so you can increase efficiency with each factor. I have some thoughts for further testing if you are interested. I love how you tested 0° bend, 90° bend and 180° bend. Is there any way you could go just a tad further? what about a 200° or 240° bend? How many more watts do you get? What efficiency does that add? So I've been wandering around the internet looking at air and water compressors and turbines and such and I'm really curious how well a scroll expander would work as a turbine. Do you thing there is a way you could test that? Also, have you tried different angles of entry? Is there a reason you always enter and leave the turbine tangentially? The angle of entry may offer more or less efficiency base on the angle of the fins. So that's easily another test you could do. I agree nozzle shapes could change your efficiency a lot as well. I believe the largest issue with your 2 stage design is the complete redirect of flow. Throwing 2 90° bends abruptly like that would cause a ton of friction and slow down the air considerably. In the interest of science and no so much practicality, You may try creating 2 exactly the same turbines and instead of mounting them side by side like you did, just make the inlet of one, the outlet of the other. Then try capturing the watts of the 2 separate shafts to see if there is any true gain. Loved the video. Keep up the fun work.

@trappy1724 Год назад

70-80% Efficient 0% Efficient 😂😂 Subscribed.

@nope2726 Год назад

I'm very interested have you considered different material for the flaps in the air drill motor like maybe 3d printered ones pla/abs?

@mafiosomax7423 Год назад

I am currently working on something similar and for me, eddy current brakes as torque-givers work great. Would you mind elaborating on what you mean by "Vibration issues"? Also maybe try printing your turbine casings with more walls, less infill. I print with 8 walls and leakage (which was a big problem) virtually disappeared altogether.

@kundeleczek1 2 года назад

Very interesting.

@stevensantos369 Год назад

I personally preferred your scooped notched design . However , I would have integrated a streamlining feature by adding a "dorsal fin" or tail on the back of each notch as an air foil In a shape much like a cross section of a freighter ship with the keel representing the dorsal fin. My logic suggests to me that it will help by causing the air to comply or conform , if you will , much faster as it tends to want to fill in the voids as it moves attempting pressure equilibrium. I also think it will help in reducing rotational resistance substantially.

@ABaumstumpf Год назад

What do you mean by "dwell time" ? Yeah, the high pressure air stays confined longer inside the turbine, but that does not add energy - it stays at the same exact size so it does not add any energy to the rotation. It will however (by chance) reduce some of the parasitic effects like when the air pushing backwards when exiting the turbine. With the later release more air will leak around and there will be a more consistent outstream of air.

@Primer595 2 года назад

Have you considered using the "disk format" of a Tesla rotary pump in place of bladed rotors. I believe the Tesla pump is up to 97% efficient. I don't know if scale causes variations in efficiency, but I know it is pretty high anyway. I wish I had a 3D printer, it's a great asset. Nice job.

@Gunzee Год назад

That was my instant thought, Tesla turbine.

@2OO_OK 2 года назад

There is a geometry called a Pelton wheel where the shape of each blade imparts a 180 degree turn on the impinging stream and should double the energy transferred.

@zyeborm Год назад

Look at the previous video in the series, he did that and it was much less efficient

@dbtest117 Год назад

I don't think the different stages should be the same size. You loose pressure in the following stages so you probably need a smaller wheel in the next stage to keep the angular speed the same. Otherwise I just think each extra stage will act as a break for the first stage.

@dbtest117 Год назад

or maybe it's larger wheel. My brain can't decide right now but I still think the break logic is valid.

@miscbits6399 Год назад

@@dbtest117 larger - and you need stators between each section to straighten the airflow if you're using axial turbines For centrifugual turbines, you need an inlet volute of some sort (this is what the delaval nozzle is about) There's a lot to be said for running separate shafts for the lower pressure stages, else they spin so fast they can disintegrate, whilst the high pressure stages aren't spinning fast enough to be efficient

@bigcatgarage7822 2 года назад

How do you think having the rotors on independent shafts would affect the output?

@sdfxcvblank5756 Год назад

my heart sank when i saw the kink in the hose

@morg7318 Год назад

love the vid, and I envy your CAD skill... 1st stage 20mm second stage 40mm?

@FilosophicalPharmer Год назад

“In theory, there’s no difference between theory and practice but in practice, there is.”

@EdwardKrapovnitsky Год назад

First and second stage nozzles have to be perfectly matched to ensure proper pressure drop in each stage. That is critical since they are on the same shaft. And first stage has to be sealed. More interesting would be to test one stage only with air outlet in the centre of rotation. And another interesting test is Pelton turbine. The first wheel design most likely needs higher reaction for better performance but more importantly blades should be oriented in a different plane so exit would be oriented towards the centre of rotation of the wheel to take advantages of better flow kinetic energy conversion. The idea is to take high speed flow and convert it to as low speed flow as possible. Only the first design attempted to do that.

@thomasvnl Год назад

At 4:52, couldn't the housing be almost 360 degree spin for the air (in practice a bit less of coursE), if the inlet and outlet are angled correctly and are positioned very close to each other?

@madtscientist8853 2 года назад

Have you looked in to a Spiral jet turbine with 12 blades In a Vortex like design That would allow it to get faster as it went down the vortex quite like a Whirl pool or black hole Or tornado

@jaxperez7860 2 года назад

what if you added a vacuum stage to the second rotor to help pull the air through ? and maybe some check valves the would open when the vacuum is below 15 psi. what if you printed a cross tube that connects the two rotors together, the hose looked like it was being choked.

@romualdaskuzborskis Год назад

I think the problem with second stage was that you left the same mass as with double size. I think you should need to cut the thickness of double stage turbines by half

@lxSNoNoxI Год назад

Thx 🙂

@David_Mash Год назад

I just started the video but I am pretty sure that I've learned that large turbines are more efficient with less fins and as you get smaller more things are more efficient. It has to do with mass of each fin and I believe production costs. That's why large windmills only have three fins and Automotive turbos have lots

@clownbooface2624 Год назад

fences and thicker rotor means more drag and increases moment of inertia, cupping the scoops like pelton wheels do wil increase power yield

@meandthecat4025 10 месяцев назад

What if you took the 180 degree and loop it back into the system at an angle that is less direct than it's primary power source? A feedback loop. I assume it kills some lagg, but not give more power necessarily. However, you're using exhaust pressurised air back into the system, so efficiency goes up in theory. However, it shouldn't be interfering with the primary power input as that could abuse some flow and makes it less efficient, so there's some play. Fun video.

@davidkatuin4527 10 месяцев назад

Enjoyed the statistical comparisons. Wondering how a tesla would compare .

@shawnmts7109 2 года назад

Keep in mind the in and out air pressure needs to be outside of the chamber so here coming in to power it's already contained the exit air needs to exit the chamber of vacuum

@innerverse1809 Год назад

And more than one nozzle with working chosen tested design parameters in effect? Then add multi-nozzle stages?

@Iowa599 Год назад

How did the input area & output area compare between the 20mm & 40mm wide turbines?

@djisydneyaustralia Год назад

Put a cap across the pickup coil to smooth your waveform

@rob1andrews Год назад

Does the mass of the turbine effect the power? Consider a bladed turbine like those used industry with inlet along the axis of the shaft and stators between stages instead of perpendicular to the shaft

@tristankordek Год назад

👍

@Iowa599 Год назад

Can you install separate pressure sensors to monitor the pressure behind each vane as the turbine spins?

@Iowa599 Год назад

My idea is the pressure difference between the vane high side & vane low side is the same as torque output. Wider vane = more torque larger diameter vane = more torque More vanes doesn't mean more torque. I'm guessing that your ports were too small, so the (larger/double capacity) vane cavities were not filling and/or exhausting sufficiently. Monitoring the pressures inside the vane cavities will tell you which is the problem. IE: several psi remain after the exhaust port = exhaust flow is restricted /&/ several psi short of supply after the intake port = inlet flow is restricted

@mackebest1995 Год назад

@Hyperspace Pirate i have a question maybe unrelated to what you are trying to do but would it be possible to build a air motor where you imput the air through the middle of the shaft and then have a it enter into a thin cylinder with a spiral channel/flute going from the middle and out to the edge making something like 2 complete turns around the axle before exiting the centrifugal force would help speed up the air flow and pull more air, in a sense the engine would help power it self. But maybe im am wrong and it is the opposite it well help pull air through faster and easier so the same amout of air produce less rotational energy of course it could be a matter os getting it right maybe the channel should be wider at the centere and get thinner further out or having crazy many rotations around the axle before it exits or having dual channels. I dont know alot about these things just something that popped up in my head when watching this and i would like to hear what you think about it? would make for an intresting project And please correct me if this just a stupid idea that wont work

@HyperspacePirate Год назад

I think that's how a centrifugal turbine works. Like the impeller on a turbocharger in reverse

@Abe8816 Год назад

@@HyperspacePirate can you please make more advancements for you turbine rotors please

@zulfikarzulkarnaenalhaq3594 Год назад

In recent gas turbine engine such as cfm56 it has 2 stage hp turbine and 4 lp turbine

@FrankBlackcrow 3 месяца назад

I think a lot of people have already done all these types of experiments with water turbines.

@PuFF1kPuF Год назад

what about water turbines? there is only 1 stage but they still are very efficient, is that because of that extracting energy from liquid is easyier?

@hankhulator5007 Год назад

Hi, what about an air exit as close as possible to the injection nozzle ? Logically, you should gain a bit of power.

@AnalogDude_ Год назад

Another design is possible, but requires a hard polished inner housing and compresses wheel with hard steel polished blades that fling out by the centrifugal forces, like in the Wankel engine roters. Can't remember where i saw it but that's how they do in industrial things.

@krankykrankster5448 Год назад

The reason your fenced designs and the 40 mm thick blade had a drop in peak torque is bc the added mass increases the moment of inertia, which will decrease the angular acceleration

@drdefecation 5 месяцев назад

concerning your Mach number calculations: isn't the p2/p1 relation you use only valid for quasi-1D flows performing no shaft work? my understanding is that turboexpanders often operate at p2/p1 of 4 or above

@Tristoo 2 года назад

god damn you do some dope shit. how did you even learn about this whole turbine thing? I get thinking turbines are cool and wanting to make them, but the maths? how do you come across that? also you never really mentioned friction, which I think may be causing you issues. and I would bet is why the big one and the one with the sides didn't work so well. even just not having them balanced might be putting a lot of extra force on the bearings, which at that speed might create some considerable friction. greased bearings will be problematic too at those high rpms. can't wait for the cryogenic stuff. I have never really been super curious about it because I've never had any use, but now I am. and by the time you're done I'll probably be wanting to do it too. last thing, you seem to know what you're doing with building CNCs, why not make yours a little more chunky and add an extra axis? seems like it would certainly make this whole endeavor much easier. thank you

@modelt8951 Год назад

I think your issue is RPM matching. Imagine your first stage wants to spin at 5000rpm at the given pressure and the second stage 4000. Because their shafts are linked the first turbine is going to be bogged down by the slower revolution rate and the second stage acting like a pump at higher rpm and wasting precious work. Similar concept in reverse. I think if you tried to get them within a few hundred rpm you could massively improve dual stage performance

@slevinshafel9395 Год назад

3:55 Why add more thicknes instead of make blade moredeep. What i mean is the R5 go more close to the center, more deep so you have more surface at same thiknes.

@user-es9vt2cv1h 6 месяцев назад

Hi Hyperspace Pirate, can I find these pieces in STL or STEP somewhere?

@krille220 9 месяцев назад

What you are making is an impulse turbin that is not very efficent with stages. So per stage you will be able to get a 1/3 of the power

@TheMrbubl3s 2 года назад

Try making the air inlet as a convergent nozzle

@lostwaryan 2 года назад

hey is there any place where we can buy all the materials?

@dedasdude Год назад

lmao KSP vab bg noise :D

@rafaelthetall Год назад

if you want to talk about some ideas and methods to optimize the design send me a message. i work with compressors and turbines.

@GeorgeTsiros Год назад

what does the spray on the glue do?

@gregoryburgundy4857 Год назад

check the scoop with the final box

@lucjannastalek9978 Год назад

you don't have to drill the laval nozzle but instead you can 3d print it flat, like your rotors.

@DUKE_of_RAMBLE Год назад

So... I noticed you didn't heh to make a THINNER turbine, to try keeping the speed up, then using a wider on stage 2, in order to extract the expansion of the gas. Also, as someone else said, that kink in the tube was an issue. A smooth curve working best, instead of say, two 90deg bends. Also, for the housing, you'll want to pay attention to the print quality. If it's not smooth, you're creating turbulence, losing efficiency...