A quickie Turbine

[Bogstandard]

Ranger,

That is one of the reasons why members should always look at the site from the beginning.

There is such a lot of information on here it really does need to be explored. And that is in less than a year, just think how much good info there will be in another year with so many members now being so active.

That is one of the reasons I give links to old posts, there are really very few new questions, just old ones reappearing, a lot of the answers are already on here.

John

 

[sivankov]

Brilliant machine!

Found this site and your turbine recently. Wondering what is the technical name for your rotor. Thought it might be a Pelton but it doesn't seem to be. Pocket rotor?

Getting a kick out of the machines on the site and hope to start a project later in the year.

Regards

 

[Bogstandard]

Sivankov,

It is based on a Pelton wheel design, but not actually one. So I gave it a name that should be understood by most.
There is most probably a correct name for it, but who cares, all you need to do is understand the principle.

John

 

[Bluechip]

Hi

Could be a 'Stumpf Turbine '.

From a memory long ago, so not too sure.

Dave.

 

[Bogstandard]

Dave,

Many thanks for that, and blast, I can't patent the damned thing. Just my luck.

Did a google search and the only pic I could come up with is at the bottom of this post.

Definitely looks very similar construction, except for the exhaust method.

But the pic does prove that care and safety is required when making turbines, and shouldn't be taken lightly.

John

 

[Julian]

John,

Nice one. Very impressive design and workmanship despite the relatives interfering.

Julian.

 

[Bluechip]

Hi John

Good Heavens, brain's not so far gone as I thought. Will restore dailly Glen Morangie ration to previous [more generous ] amount.

Your post suggested a connection with Flash Steamers, and sure enough there is a section in 'Experimental Flash Steam' about the engines.

A figure of 95,000 rpm is quoted!!

Little wonder it let go, I'll give 'em a miss, I think.

Too old and cranky to dodge the flying bits now.

Dave

 

[BobWarfield]

Very nicely done, Bog. That's a wonderful gorgeous model that I'm sure would delight anyone who sees it in operation.

I'm curious about the power output of these turbines. Clearly it is making some power into you generator, and you've written about making a steam turbine for a boat enthusiast.

How does the power compare to a piston type steam engine? Have you ever heard of a rule of thumb to size one to get performance similar to a piston? Is power available at lower rpms, or do they have to spin up to operating speed without much load first?

Just curious,

BW

 

[Bogstandard]

Bob,

My three rotor turbine was built as a prototype for trials to see if it was a viable proposition to power a model boat.

http://www.homemodelenginemachinist.com/index.php?topic=1500.0

At the end of it all, I decided that he would not be able to produce enough steam in the available space he had in the boat. So that contract didn't come off, but at least I ended up with a nice little 'shifter'. If it had carried on, they would have ended up as a pair of slightly smaller twin rotored ones.

The power band on these low pressure engines doesn't really show until you start to hit the higher rev ranges (maybe 10K and above), once you get to over 30k, all hell breaks loose and unless you can control it, they will run away very quickly. So in reality, to extract useable power from them, they do need to go thru a reduction gearbox, I should think somewhere between 15 and 20 to 1 reduction. Also at the higher speed, the gyroscopic effects really start to show themselves. The single rotor one was hard to hold when running at a fair wack, it just wanted to spin your hand off at the wrist.

I cannot give any figures as to power output or input, as I have never measured them. Just my observations. Only one thing to say on it, they are greedy little monsters because of their built in inefficiencies. More nozzle and blade shape modifications would be required to even get anywhere near efficient. But not having gone any deeper into it, and not wanting to, I hope someone one here might take up the challenge and produce a good 'un, rather than ones that make a noise and spin fast.

John

 

[firebird]

Hi John

Fascinating post, Iv'e followed it with great interest. One of my jobs yesterday was to fit a new water pump and cambelt etc to a vauxhall omega. With the pump in my hand looking at the impellor all sorts of strange ideas started going through my mind. Heres the pump, pulley side

Heres the pump impellor side.

2 minutes later after a trip to the press.

Heres the impellor

What do you think????

Cheers

Rich

 

[baldrocker]

Rich
Oh I do love that sort of thinking, go for it,
if it works I'll copy it and tell everone it was my idea :

 

[CrewCab]

if it works I'll copy it and tell everone it was my idea :

behave Paul : 8) .............. don't you have a Myford lathe to rewire



as it happens I have to rewire a Boxford on Saturday, stand by your "Inbox" ............. I may well need help ;D

CC

 

[firebird]

Hi

I might not have the time to pursue it at the moment, I'm too busy on my boiler project. I was hoping to persuade Bogs to take it up but something strange is going on there?

Cheers


Rich

 

[sivankov]

John,

Thanks for your reply to my earlier post.

Hope I didn't come off as coarse when I wrote "pocket rotor?". I was merely offering it up as a possible term for the device not realizing you had already referred to it as such.

Also, thanks to Dave for the "Stumpf" info.

sivankov

 

[dparker]

Rich: The rotor you pictured would work for a turbine but you will need to make a close fitting cover to fit the vanes to minimize the leakage around the vanes. This runner would also use quite a large volume of air to get any amount of power out of it.
The company I ran the test lab for, built water turbines (Francis style) using their centrifugal pumps and running the water flow through them backwards. With enough water and pressure they were quite efficient and would produce useable power. The pumps were somewhat altered to give the water a smooth flow path into the runner but this did not alter the pumping ability much. We built them on 3 phase induction motors and put the power back on the grid.
don