Making a steam turbine generator

[Aaragorn]

I am trying to reverse engineer a steam turbine similar to the one these guys are using.

http://www.youtube.com/watch?v=4h9FLvj2ZJM&feature=related

http://www.iaus.com/default.aspx

I made a two jet version of this using 1/4" steel tube mounted to a 1 1/4" Pipe tee to house the bearing and fed thru the center of the bearing by a 1/2" steel pipe.

The jet in the end of my rotor tubing is one 1/16" hole in each of the two rotors at approximately 14" radius from center of the rotor.

I hooked the thing up to my pressure cooker on the stove to see if it would turn the motor. I couldn't develop sufficient pressures to make it turn. I had a 5' long 3/8" flexible tube from the cooker to the intake. It seemed to me that it didn't have any leaks. So the only venting of steam was thru the two 1/16" holes in the ends of the rotor. I'll bet I never even developed 10 psi during my test despite letting the pressure cooker get going at a rolling boil for several minutes.

it amazes me that only two tiny holes can vent so much and still not produce enough pressure in the system to turn the rotor.

How can I change this set up to generate the kind of pressures I need to turn the generator.

My end goal here is to use a solar collector to make this steam turbine generate power. It's only a 2.5 hp motor and it doesn't take much effort to spin the rotor by hand. But spinning it by hand isn't my goal here is it.

I don't know anything about fluid dynamics and how to make a higher pressure system. Please guide me how to do this.

 

[Aaragorn]

I think I know why I lost pressure in my test.

I think the thermal losses from the pressure cooker to the end of the rotor were such that the steam condensed en route.

I'm going to have to fabricate insulation through out the piping and rotor mechanism. What concerns me is that I don't want to melt the rubber seals in the main rotor bearing. I believe they are good up to approx. 390F but since this is all experimental to me I don't want to run temperatures any hotter than I need to in order to get the output result I'm looking for.

 

[gerhardl]

The principle is not exactly new: Heron in BC 100 published the jet driven steam turbine idea:

http://www.quirao.com/en/p/inventions/steam-engines-/24009/dampfball-messing-gintschel.htm

It is of course posible to calculate the correct balance, although it will require some knowledge on steam properties and involve some calculations on heat transfer.

But yes, I think you are on the right track. The whole idea is to transfer so much heat that you build up sufficient pressure in a sufficient reservoir to balance the outlet of steam through your openings.

In brief I think your openings are far too large. You will not build up much of a pressure before you choke the outflow from the jets. Theoretically this will be at the speed of sound. A rough calculation will tell you how much volume of steam this will need at a given diameter opening.

Another thing: when you first start to build up overpressure you need to control it, not to explode your whole contraption.

Be sure to include a safety pressure valve with sufficient capacity, set at a low enough pressure. Secure outlet for safety valve and security for fragments and hot steam in place if an explosion after all should take place must be included.

The history of early steam engine development has a lot of nasty accidents, but the knowledge on how to cope is still there. Be sure to fetch in what you need in knowledgde and sequrity from companies dealing in steam equipment and other sources!