Steam turbine, which of the design is effective??

Jens - Do not be put off by the thread above. Have a go but be aware

1. Small turbines are greedy for steam. Successful units tend to use waste steam.

2. Small turbines are FAST. I had one go up to 2 million RPM before it disintegrated. The aircraft Gyros run at about 14-16,000 rpm. They run in a partial vacuum because the air is sucked into them, but NO power is taken from them (except overcoming friction).

3. Their efficiency is abysmal. I was after power output.

4. Both Stumphs and DeLavals are not so difficult to make if you make the correct tooling.

5. You will have 3 or 4 BIG problems

a. Bearings, you will ‘fry/curry’ them by the dozen, But things have moved on in the past 20 years,

b. Reduction gears – I often got the dreaded ‘Grrrrr-wheee-poof’. As the gear stripped, the turbine ran away and disintegrated!.

c. The physical strength of the turbine wheel. Calculate the internal stresses on your wheel at 2,000 rpm, 20,000 rpm, 200,000 rpm and finally at 2,000,000 rpm. It is horrendous.

d. Nozzle design. In these sizes remember you are well down into the boundary layer.

6. Beware there are many claims and conspiracy theories about Tessla’s turbines and the rest of his works BUT that is enough of that.

Go for reaction turbines, I did try an expansion turbine, a lot of work and I could not get it to spin. I did but the clearances were too large.

I am afraid my note books vanished some years ago

Edited By Jens Eirik Skogstad on 04/05/2011 19:50:30

Edited By Jens Eirik Skogstad on 04/05/2011 19:57:56

Jens your results are very interesting. When I was trying to build the things one of my problems (amongst many others was) fried bearings. Some of which were from a very expensive supplier and two sets few given to me by a company which made ‘air driven’ aircraft instruments which ran at about 15,000 RPM.

The best which lasted about 35 minutes total running time were made of the carbon rods from old dry batteries. The shafts were piano wire used on a Spinco ultra centrifuges. They survived three stripped primary drive gears.

Edited By Richard Parsons on 05/05/2011 12:49:28

Today i tested with steam with good results No problem with ball bearing with diesel oil, no mixed with water. The turbine ran above 35000 rpm with good torque. When i removed the heat of the boiler, the steam turbine was still running up to 2 minutes before the pressure was dropped of.. there was enough torque.

I am uploading the movie of my turbine in Youtube.. ready to see later..

 

Edited By Jens Eirik Skogstad on 05/05/2011 23:06:11

Edited By Jens Eirik Skogstad on 05/05/2011 22:54:22

Edited By ady on 09/05/2011 23:46:58

Michael - The work I did started in the early 70s with the Stumpf type turbines. Because of limitation in machining capacity (a little Unimat SL) I was limited in sizes and materials. It sort of worked making a ‘wee-ing noise’ when running on low pressure air, but it had no power. It would stop if you looked at it cross eyed.

I read everything I could find in the County Libraries –not much- I admit. But I came across the DeLaval turbine and nozzle. My early DeLaval wheels were simply slots sawn at 45° across the disk and nozzles were made using clock maker’s broaches. These disks were easier to make than the cutters for Stumps type. More by luck than judgement the blades on my second DeLaval over lapped. It looked promising especially when it disintegrated (on air). It was then I saw an illustration of a DeLaval which had its nozzle at 70° to the axel (20° to the plane of the disk). This I discovered had been done to reduce the effective velocity of the air/steam flow. I steepened the blade angle which were ‘slab sided’. As things were so small, I did not think that aerodynamic shapes would have any effect. About 1973 I had saver up enough cash for a Myford ML10 which being more rigid allowed me more scope. I also met the late Professor Chaddock and as a result I started to make curved blade rotors. I did nothing between 1974 and 1977 moving house and work etc. But in 1978 I was given an old Oscilloscope and by attaching a magnet to the turbine shaft I could measure the rotational speed of the disk. It was getting frightening, but I noticed that when I connected up the circuit I could hear the turbine slow down. I tried making annular nozzles (sort of 2 dimensional venturi with vanes in to direct the flow). I even built a 4 stage Curtis unit (never again). I was still getting less than 2-5% of the theoretical output. Or ‘louse power’ as I described it in a letter to Professor Chaddock.

It all came to a stop when I came to the ‘notice’ of the ‘local authorities’. I owned a dog and my new neighbours were Moslems. They did not care but the ‘Authorities’ did and they wanted the dog to go. So for the next year or so I was involved in various legal battles with the ‘authorities’. All of which I won, but they seldom paid my costs. Their eternal excuse was that these ‘expenses’ were not in this year’s ‘budget’. These sorts of niggles rumbled on including my shed being opened (in my absence) and sealed for 2 months by ‘Elfin Safety’. This went on until I just ‘vanished’ early in this centenary. You cannot ‘buck’ city hall.

I am afraid all my work notebooks and drawings from the 70s and 80’s were lost/misplaced/removed etc, but if I can get the metal I might restart work.

Ian and folks there, how can i calculate the effect by generator and volt/amper if the rpm is known?

Edited By Jens Eirik Skogstad on 02/06/2011 14:42:48

Hi all folks!

I has tested the steam turbine with propeller in water under load. See the two movies here:

Edited By Jens Eirik Skogstad on 19/07/2012 05:26:09

May I thank you gentlemen for posting

I just happened across this thread, and have learned a lot.

... That old Model Steam Turbines book is fascinating, and your expert comments bring things nicely up to date.

Anyone interested in Dynamometers might find it useful to look at Magtrol.

[they generously provide PDFs of their Manuals]

MichaelG.

Edited By Michael Gilligan on 19/07/2012 08:31:40