Turbine Number Eight

[WXYZCIENCE]

March 2007, I posted the first pictures of an eight inch turbine that was under construction. Here is a picture of the unit last year.







The roughed out disks sat on my shelf till last week. I found an eight inch Flexatolic stainless steel ring that fit the description of what would finish the disk. Here are two pictures of the finished turbine disk.







A small lip was machine on the inside of the ring. Next the two plates were machined with the opposite lip. Then three bolts tie the whole assembly together. The 1/16" plate serves to cover the balance holes and a slinger for water.







The entire disk assembly was balanced and polished. It came out very true and will be operate around 10,000 rpm. The alternator will be directly connect and designed for 500 watts at that speed. Next the bearing and housing. I hope it will not take another year.


Joseph.

[JW]

I like it Joseph,

 Keep us posted on the progress. Its not uncommon for such type of projects to take a while to complete. You will get alot of personal satisfaction when you get the the project spinning and producing some power.

JW

[hvirtane]

A very interesting project.

What is the estimate of the steam power, you are thinking to feed it?  

- Hannu

[JW]

This will help the reader to put things into perspective.

http://www.fieldlines.com/story/2007/3/1/5259/19738

this is where I cought up to you

http://www.fieldlines.com/story/2008/1/13/214327/136

Honestly, when I read the title to this, I was expecting to see a wind-turbine, perhaps the 8th one built?

Anyhow enjoy the links all.  

 So, is this the inter-stage turbine to the assembly, I like your solution, im curious at to the nozzle configuration.

JW

[hvirtane]

I remember this project. But did not remember well discussions concerning the power.

Earlier Brian H wrote:

First, and foremost, removing any entrained water droplets from the steam, no matter how small. Your steam needs to be 100% water vapor(well at least 99%), with no entrained droplets. Conventional steam plants accomplish this by means of superheat. Superheating (heating above saturation temperature) ensures that no "carryover" of water droplets makes it's way into the turbine. The main reason for this is the extreme velocity that steam leaves the nozzles. Any entrained water droplets will act just like tiny bits of sand at that high velocity, and will impinge on your vanes, and quickly erode your turbine wheel, no matter what it's made of.

I think that Brian H is right. Is there any way to overcome this difficulty (to make the wheel to stand without excessive costs)? There have been some developments of such kind of 'semiturbines', which would partly accept water in the turbine, but I don't know about their success.

- Hannu

[WXYZCIENCE]

Hannu, I constructed a tube boiler last year that is fired by wood or coal. My best guess at the output power is around 200,000 btus. Most steam boilers have to have a good hot fire to produce steady steam. I expect around 10% efficiency in the turbine stage and the co-generation into my green house will use up most of the heat. Progress should speed up now that the hard work is complete. I will post pictures and info as soon as it is working. Thanks for your interest.
Joseph

[JW]

I just want to chime-in on something, that I feel is very relevant.

 Almost all, small-scale flash-steam power-plants, feature such a short- return-path with the condencer-scheme employ'd, that most such systems, 'do-not' feature a blow-down circuit, within the boiler circuit/cycle.

 In fact, most such small scale systems, are filled with purified-distilled water to begin with. So, there are no dissolved solids to 'blowdown' if you will.

 In general, 'impinging' of the blading, is minimized thru working fluids that have no dissolved solids when condenced, or in the 'semi-state', between vapor and liquid.

JW

[joestue]

Could you be specific as to what the efficiency means?

10% is rather high for low pressure systems, when taken as heat input to shaft output.

I'm also interested in the running conditions, ie. KPA, temp, condenser vacuum etc.

I've been trying for the past year to design solar steam..... but not to change the subject. if you can actually get 10% that's great.

[WXYZCIENCE]

joestue, steam is easy to generate and water is non toxic. Efficiency of steam in a single stage unit is related to the viscosity of the working fluid. I base my calculations on water entering the boiler at 190 degrees F. and steam leaving at around 350 degrees but until I actually test the unit these are not firm. You are correct, if I can achieve 10% it will be great.


Solar working fluids that are non wetting such a toluene have been successfully used for very high efficiency in a single stage turbines. I don't see myself wanting to go that direction.
Joseph.