Tuesday, February 14, 2012

Turbine engine parts... what 'n the heck are these?

These parts came from a stationary turbine engine we have had in our school shop for some years. I nursed notions of trying to fire it off... but now am glad we never did.

We had some of the boys tear it down for the fun of it, and will be scrapping the remains. Inside we found gears missing enough metal to build a rockcrusher transmission. Most of it we can decipher.... but not these.

These 'discs' are geared to spin, and are placed directly in the exhaust stream of the turbine. All the exhaust passes through these discs before exiting the engine. They are roughly 25" in diameter, and 3" in thickness. They are composed of a metallic honeycomb that is goldish in color. The metal is magnetic. Despite their size, I can easily pick each up by myself, or hold one up by one hand if I wished to.

What are they, and what is their purpose?
What is the honeycomb metal?

A 'scrap metal expert' pronounced them to be carbon steel with some kind of rinkers coating.
"Ah know xactly what dey are.... Give you numer one steel price for them".

Seriously... what are they made of, and what are they for? A couple of the kids are just dieing to know.... and me too.


Rev. Paul said...

If I remember my turbine engine class correctly (nearly 40 years ago, so don't fault me if I'm wrong, please) those honeycombs are seals to control compression levels.

Carteach0 said...

I suspect there is much here for me to learn....

I thought their placement in such a way the exhaust had to completely pass through them would indicate them to be some kind of catalyst to burn off particulates from the combustion process.

On the other hand, I can see them perhaps limiting exhaust flow as well.

I am still perplexed :-)

Richard said...

Did they rotate in to the intake air stream? If so they are probably the heat exchangers for a regenerative cycle gas turbine. Search for "regenerative cycle turbine engine design", go to the PDF on the UTulsa link and go to page 13. I think that will answer your questions.

Rick T

Richard said...

I think I may have an information source for you: http://www.osti.gov/bridge/purl.cover.jsp?purl=/6897881-hkmPxj/

This is a link (I know, Rule D applies)to a DOT/DOE report on putting gas turbine engines in Transit buses. There is an exploded assembly diagram on page 14 that may match your unit.

The bus connection may be a clue as to how your auto shop got its hands on the thing....

Rick T

Richard said...

Final comment: I will bet you are looking at a nickel alloy for the honeycomb material, not Iron... To quote another site "Nickel-base alloys are used in many applications where they are subjected to harsh environments at high temperatures. Nickel-chromium alloys or alloys that contain more than about 15% Cr are used to provide both oxidation and carburization resistance at temperatures exceeding 760°C."

Sounds like gas turbine heat exchanger duty to me.

Can you share the nameplate information from the unit?

Carteach0 said...

Richard, the diagram in that report matches the engine we have. Thank you.

The engine came to us as military surplus, and I was told it came from a stationary generator setup.

og said...

Nickel-chrome. Probably Inconel. Used where corrosion and temperature resistance are important. If this is just gonna be tossed, take an acetylene torch and see how much it takes to melt it. You'll be amused.

Inconel is the metal used to make most turbocharger impellors, because they can actually be glowing red to almost white hot and not be dimensionally affected by the heat.

Carteach0 said...

So Og... I gather their value as scrap metal is probably limited. For their size, their weight is not all that heavy.

But... they are far too cool to just let slip away for nothing. Their must be SOMETHING useful I can do with them.

I was wondering.... any reason not to mount one over the fire and try it as a steak grill :-)

Carteach0 said...

ERp... I just checked the price of scrap on 'Inconel'. Too ritzy to use as a grill, if this stuff really is that super-metal.

The trick will be ID'ing it I guess. The local scrap yard went through three Billy-Bob-Idunnos till they found one man who pronounced it funny looking carbon steel. Period. Don't question the man, cause he's the only one allowed to drive the big loader since Cooter ran if off into the pond.

They were unable to do any testing at that location.

Anonymous said...

Inconel won't attract a magnet, and a spark test on a carborundum wheel will give you reddish long streaks (as opposed to yellow or whote from stainless or carbon steel)

Inconel is actually very heavy, but you have a honeycomb of foil. Assuming you can get a pan big enough, sit it in a pan and work all the bubbles out (you might use a dab of dish soap to reduce the surface tension) and establush the volume, then weigh. For Inconel 608 weighs .307 lbs per cubic inch.

Carteach0 said...

Well, these will attract a magnet, without a doubt.

Maybe I'm back the to the awesome steak grill idea :-)

Anonymous said...

I just reread the post and realized what they might be- catalysts. The color is probably a platinum alloy. Still could be worth a few dollars.

Carteach0 said...

I have a date tomorrow to get them hit with a XRF gun, and then I'll know exactly what they are.