First Test of a DIY Steam Turbine running off a 4" Copper MSM Boiler.

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vederstein

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Good looking turbine.

May I suggest using Kynar tubing for a plastic steam line. It's good to 400 deg F. Granted, it's not the cheapest plastic tubing around, but you'll know that it'll handle the heat.

...Ved.
 

skyline1

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Nice to see another sufferer from "Turbinitus" It's quite incurable you know once you've got it you can't ever completely get rid of it.

Seriously nice little turbine she goes well, you probably don't need the flywheel as the rotor itself will act like one to an extent.

It looks like a Stumph type with straight on steam admission mine are Delaval's where the steam comes in at about 30 Degrees to the rotor axis.

As a fellow turbine nut (see my avatar) I would love to see some more details on this one.

Best Regards Mark
 

Steamchick

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Hi Jim,
I am the odd-ball who harps-on about safety all the while.... and it is just because it was a part of my job to keep safe working practices working.
So to get rid of the safety bug:
We all use certified boilers. Tested and maintained - for safety. So while it is convenient, and simple to fit you are using a hose that pops-off when the pressure in the pipe gets up a bit. (AAARGH!!!! Please don't). As you will be aware - but some innocent person watching may not be so aware - the steam in the hose is clear, will take the flesh off your bones instantly, and make you scream if you get it on your bare flesh. So Please at least use a hose that will take the pressure - certified to at least twice the safety valve lifting pressure - at the temperature of the steam, and CLAMP the hose onto the fittings. You know it makes sense.
The water vapour at the exhaust is hot and wet, but not nearly so dangerous, as it has already expanded to atmospheric pressure, doing a lot of work in the process and hence cooling (some in the turbine). I see you keep well away (because you have a notion that there is some danger in what you are doing?), but an on-line by-stander may not appreciate the safety issues, and be led to thinking steam is "safe".
One other thing that you probably know, the SAFETY VALVE - is there for safety, NOT for regulating the boiler pressure. EVERY trained stoker/engine driver/Boiler monitor or whever will maintain a boiler at the WORKING pressure - without having the safety blow all the time (Which I think you did, but the explanation was missing)... BUT as a demonstration that the safety valve is blowing at the correct pressure, then it is the right thing to do. (The first time at pressure at every firing - Normal practice.). It just needs a better explanation in your video.
Nuff said.
Lovely looking turbine, but can you connect it to a generator or something so we can see it doing some work? - Then maybe you can demontstrate the power of the turbine by showing what pressure you can hold at whatever load on the turbine? After all, it is a model of what makes the electric lights come on when we throw a switch!
Oh. and a bit of technical stuff about the turbine being a Reaction turbine, or Tesla type? - Diameter? Number of blades? or whatever...
Guddonya mate!
K2
 

JimDobson

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Nice to see another sufferer from "Turbinitus" It's quite incurable you know once you've got it you can't ever completely get rid of it.

Seriously nice little turbine she goes well, you probably don't need the flywheel as the rotor itself will act like one to an extent.

It looks like a Stumph type with straight on steam admission mine are Delaval's where the steam comes in at about 30 Degrees to the rotor axis.

As a fellow turbine nut (see my avatar) I would love to see some more details on this one.

Best Regards Mark
G'day Mark,

As a MKI, there's always improvement to be had in the MKII and MKIII versions :)

I have really enjoyed this turbine and I do think I have a case of 'Turbinitus' now! Below is what is inside this one.

Fan.jpg
 

Steamchick

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Hi Jim,
See if you can get hold of a tidly little book called "model steam turbines" by H.H. Harrison... That will teach you everything except about Tesla's design for a turbine. The thinking for early turbines - and where you seem to be starting from - is the simple impulse wheel jet reaction turbine, although Hero (an ancient Greek) made reaction turbines. "Gas" (or steam) reaction turbines like this can effectively only be about 50% efficient (max) this way (laws of physics). So Pelton wheel turbines were designed to increase efficiency by having curved blades. Parsons realised the benefits of multi-staging and created his turbines - the pre-cursors of today's multi-stage axial flow turbines - as a result. Modern understanding of aerodynamics now creates improved efficiency of flow over the aerofoils so low pressure is developed over the outer curve of the blade as well as less turbulent and higher efficiency energy transfer from velocity to force on the blade on the concave surface of the blade. Thus the book mentioned takes you through ways to make more complex turbines to better understand how and why they work as they do.
Tesla, however, designed turbines in a completely different way - utilising skin friction to transfer energy from the jet of gas/steam to the rotating armature. By feeding the jet to the outside of the surface of a disc, as the jet of gas/steam slows it naturally travels towards the centre of the disc in a spiral. When this "hits the optimum" rotor speed, the efficiency leaps from 50%-ish to well over 80%-ish as the jet travelling across the surface of the disc imparts energy in thousands of tiny stages, so becomes incredibly efficient. Demonstration models have run up to 60,000rpm at full steam, then leapt to 100,000rpm when they hit the "tuned" optimum gas flow... and then produce much more power for the same steam as needed to get them up to 60,000rpm. - Now that is a possible direction for you?
And it is all Turbinitis!
K2
 

Steamchick

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G'day Mark,

As a MKI, there's always improvement to be had in the MKII and MKIII versions :)

I have really enjoyed this turbine and I do think I have a case of 'Turbinitus' now! Below is what is inside this one.

View attachment 121877
Next step is to make another rotor for that turbine, but with curved "Pelton wheel" styled blades.... Then a third rotor using multiple discs as the Tesla design. But may I suggest you couple-up a small generator so you can develop some power and measure the improvement for each design? Also, try shaping the steam nozzle to an expansion cone (de Laval nozzle) to accelerate the velocity of the steam to sonic speeds?
K2
 

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In case anybody else was intrigued by Tesla's turbine:


Craig
 

Steamchick

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Steamchick

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Hi Jim,
You may understand the Tesla Turbine better from these instructions. I haven't made one (yet) but understand 2 important fundamentals (from what others have impressed upon me):
  1. Balance: The rotor must be balanced very well, as otherwise it won't attain high revolutions and will scrap the bearings! This also means a stiff housing and stiff shaft are needed, but with small high-speed bearings... (100,000rpm).
  2. Steam nozzle: carefully make a good De Laval steam nozzle - to maximise steam velocity and therefore efficiency at the nozzle. This means you get the max velocity of steam reaching the turbine rotor, and greatest efficiency overall.
  3. I said 2 important fundamentals, but the third is 3rd priority, but good advice all the same. Thin discs, and thinner gaps. And lots of discs to make up the full width of the nozzle.
The key thing overall is that the steam transfers energy to the rotor by rubbing on the surface of the rotor... basically surface friction. That does not mean rough surfaces, just "more surface, less gap" as a principle. The jet of steam needs to be close to tangential to the edge of the discs, "nature" will determine how it flows in a spiral towards the centre and exits the stack of discs. So the faster the steam, the more surface there is and how fast the rotor will spin before the bearings destroy themselves are the "fun and games" of designing a good Tesla Turbine. Remember, the periphery of the rotor cannot move faster than the velocity of the steam... so "sonic" steam exiting the nozzle defines the ultimate limit for the speed of the turbine.
Cheers!
K2
 

skyline1

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Steamchick

I agree completely with your fundamentals for good turbines and the first two apply to any turbine not just a Tesla turbine

Balance

Absolutely essential to get the best out of them. It is a slow and painstaking process but well worth it. I have a method for doing it which needs no expensive equipment and I have found it works really well even if it is a bit slow.

You take two ordinary woodwork handsaws and clamp them in the vice either side of a block of wood a little wider than your rotor then use a spirit level to level them both lengthwise and across. you place your rotor on it's shaft on these so it can roll freely. Then gently roll the rotor and you will find that it will tend to settle in one spot. mark this with a felt tip pen at the lowest point and remove a little material from close to the centre of the rotor at this point.

Repeat and repeat this until eventually the rotor settles completely at random with no heavy spot your rotor should now be fairly well balanced.

My late father could spend days and days doing this and used to say he could tell when the rotor was getting more balanced as he was getting more unbalanced.
It's slow but effective. Where I worked at one time they had precision balancing machines so I took my little rotor in and got them to check it. They spun it up to as fast as the machine would go (about 15,000 RPM IIRC) and couldn't find any imbalance at all.

Nozzles

If you are running on steam a diverging Delaval nozzle makes a great difference to performance as turbines rely on velocity not pressure and the diverging nozzle reduces the steam pressure whilst increasing the velocity ( Bernoulli's law) I make mine, believe it or not, from the brass ends of ball point pen refills.
You simply knock out the ball with a piece of steel wire and you are left with a little brass tube with a series of steps in it. you then gently ream these away with a tapered "D" bit reamer the taper should be 1 in 20 if memory serves but I may be wrong. These can then be put in a carrier and make super steam nozzles.

I hope these two "dirty tricks" will be of help

Best Regards Mark
 

ajoeiam

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Hi Jim,
You may understand the Tesla Turbine better from these instructions. I haven't made one (yet) but understand 2 important fundamentals (from what others have impressed upon me):
  1. Balance: The rotor must be balanced very well, as otherwise it won't attain high revolutions and will scrap the bearings! This also means a stiff housing and stiff shaft are needed, but with small high-speed bearings... (100,000rpm).
  2. snip
K2
I would suggest using 'plain' bearings.
Yes it would rob some energy to maintain a pressure on the lubricating oil but your maximum rpm shouldn't really have a limit.

Went looking to make sure I wasn't out to lunch.

Well - - - - air bearings are quite capable of such speeds but then I found this Angular Contact Bearings | GMN Bearing USA"angular%20contact%20bearing"&msclkid=7ada2611a685198fd7c479e4110b499d .

So - - - - seems options to well over 250k rpm exist - - - WOW.
 

Steamchick

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Maybe I'll get a pair - then say I have started making a Tesla turbine! The only limit is the sonic speed of the air/steam jet. The turbine can't go faster than the driving gas velocity.
K2
 

Steamchick

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ajoeiam
I like your comment "your maximum rpm shouldn't really have a limit." but - IMHO - the Laws of Physics define limits for the universe, then Scientists modify this with the statement "known universe"! And our imagination has no limits! Ergo, you are right that we should have "NO LIMITS"!
Just listen to great people DELETED POLITICAL STUFF.
 
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JimDobson

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Nice to see another sufferer from "Turbinitus" It's quite incurable you know once you've got it you can't ever completely get rid of it.

Seriously nice little turbine she goes well, you probably don't need the flywheel as the rotor itself will act like one to an extent.

It looks like a Stumph type with straight on steam admission mine are Delaval's where the steam comes in at about 30 Degrees to the rotor axis.

As a fellow turbine nut (see my avatar) I would love to see some more details on this one.

Best Regards Mark

Mark do you have any photos/videos of your turbines?
 

skyline1

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Hi Jim

I did have many of them but I can't find them anymore they may have been lost during a recent computer failure.

However I can take some more and to keep you going, here are some I recovered from previous forum threads


DSC_0025.jpg
DSC_0028.jpg
DSC_0029.jpg
DSC_0034.jpg
DSC_0045.jpg
DSC_0047.jpg


A few points to note

The CD pictured in the first one is not part of the model it is just to give an idea of scale

The blurred picture of the coupling close-up is due to the fact that I was leaning on the bench the plant was on to take the picture and the vibration from it was shaking the camera.

Best Regards Mark
 
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