Luc's Industrial Gas Turbines

[luc]

Hi all ...

I'm starting a new project with two brand new Garrett GT2560R turbos coming my way as we speak ...

The goal with this project is to build a "Low Cost - Free Turbine" gas turbine concept, a bit like a PT6, but much smaller and much cheaper and see how much HP and/or torque can I get out of this "Pair", one driving the other.

For this, I'm planing to use the good and "Reliable" John Wallis flame holder hole area calculation based on the turbine "Inlet" area and NOT the compressor inlet area like Springer would suggest.

Now, I heared dealing with pretty small turbos can be a pain in the (You know what), thus, I'm asking here before spending thousand of $$$ in parts ... "Any comments and/or suggestions and/or warnings before I start???"

And as for the "Ejector" modeling and CFD analysis John, I'm now pretty close to the best results I can draw from this one with only 1 or 2 CFD to do, and I'm now up to 1.36 lbs/sec sucked out that cabinet ... That's ALOT of air for such a small ejector gap ...

Thanks and cheers to you all guys ...

[racketmotorman]

Hi Luc

The GT2560R turbos won't work

With a 46.5mm comp inducer -1698 sq mms , we'd normally require a turbine exducer area at ~25% bigger , or 2122 sq mms or 52mm diameter , the GT2560R has a very small turbine wheel of 53mm inducer but with a 62Trim it only has an exducer diameter of ~41 mm .............................way too small .

Don't waste your time even thinking about using them

Cheers
John

[luc]

Okeyyyy ...

Why do I sudently feel very very BADdddd ... The suplier not only providing these two babys new a free to us, but us spending 700$ worth of accessories ...

What the ECK did I miss here ... DAMN IT ... That's a Gad Damn 2,200$ US Flunk ...

God Damn it ............

[luc]

Okeyy ... Numbers validated, the GT2560 turbine exducer is (-)19% or 19% smaller compared to the compressor's inducer ... Bomber (Why the HELL didn't I check that before ?($$/$&%(&?%))(&?%(&(?$/*?%)*)*& ...

Can we work around that before I have to return a shit load of stuff and loose a shit load of money in the process?????

As for your comment

we'd normally require a turbine exducer area at ~25% bigger

... You do remember that I have two "Working" turbines here running with GT4708R, thus, an 8% difference between compressor inducer and turbine exducer areas ... You do remember don't you ...

Can we work around that (-)19% for this one???

Thanks,

[racketmotorman]

Hi Luc

Your GT4708R units aren't "working hard" , they're running rather cold so the relatively small turbine stage isn't a problem , once you get a turbine "working" with T I Ts of 900 C and above, the lowered density of the gases soon cause problems with undersized flow areas , we soon go into surge

The GT2560 is also a "low compression" turbo , its 60Trim comp map topping out at a 2.5 :1 PR , this will further exacerbate the density/flow area problems , at that 2.5:1 PR it has a wide flow range of between 15 and 30 lbs/min , ideal for a SI engine but crap for a gas turbine.

You might get the GT2560 engines to run , but mass flow will be at the low end and at poor efficiency necessitating a high PR across the poor efficiency ( 65%) turbine stage to get the engine to run leaving not much energy for making power .

the GT2560 turb stage has a corrected flow of ~14lbs/min at a 2:1 PR , this would equate to roughly an actual flow of ~16 lbs/min right on the comp surge line if using a TIT of ~900 C , but the comp will be running at ~65% efficiency and sucking lotsa horsepower ..........................you'll burn heaps of fuel for not much power output .

The GT2560 is a good turbocharger , but an extremely poor candidate for making into a gas turbine .......................don't waste your time and energy , there are better turbos to use .

Cheers
John

[luc]

Hi John,

And again, thanks for the input. I'm trying to work a deal to maybe return the two GT2560R in exchange for either two GTX2860R (Rally) @ 25% or two GTX3067R @ 22%. Other then "Price" since they are "X", their length is still within margin since one of our main goal here, is to build this system as small as possible.

None the less, I will raise the two following questions considering the above deal is still not certain and I might have to do with the GT2560R;

The GT2560 is a good turbocharger , but an extremely poor candidate for making into a gas turbine

This said, you do remember that our goal here is not "Thrust" nor "Torque", but simply drive another identical turbo using the exhaust gases of the first one, like for a "Free turbine" like PT6s. In that case, could we "Lower" the requirements and still use them? Bare in mind I'm not arguing here, but simply asking to explore all avenues before throwing 2,200$ down the drain maybe.

there are better turbos to use .

Maybe ... But at what cost to us now? ... That's the question.

Bit at the end, we will do what we have to ... And by the way, have you looked at my "Turbo Finder Calculator" published on the Gas Turbine forum section. Hope it will prevent others doing the same mistake we just did, although I'm still puzzled how this one got by unnoticed ... Maybe getting to old for that stuff or I'm overworked, for I do have ALOT on my plate these days ...

Cheers and thanks ... Like always ...

[racketmotorman]

Hi Luc

Let me get this straight ....................you want to feed the output from the GT2560 into another GT2560 , this is even less likely to work , any freepower turbine will need to have a flow capacity twice the gas producers due to the lower gas densities and velocities achievable from the low pressure ratio across the freepower stage .

A good gas turbine turbo should have a low compressor Trim , preferably <50 Trim and closer to 40 Trim , this produces higher pressure ratios without inlet choking due to inducer tip shock waves ..............high Trim wheels like the 60 Trim GT2560R are designed for spark ignition engines , not gas turbines .

Could you expand on the general outlay of your design , whats the desired outcome , application etc etc ...................it'll help me get a grasp on where we're heading here

Cheers
John

[luc]

Hi John,

Let me get this straight ....................you want to feed the output from the GT2560 into another GT2560

Yeapppp ...

A good gas turbine turbo should have a low compressor Trim , preferably <50 Trim and closer to 40 Trim

So, my GTX3067R is a much better choice compared to the GT2560R, and I just have to size and select the "Slave" (Driven) turbo now ... Any suggestion???.

Could you expand on the general outlay of your design , whats the desired outcome , application etc etc ...................it'll help me get a grasp on where we're heading here

Certainly buddy ... We've just discivered a market that not only would welcome, but would EMBRASSE the arrival of a thermo generator that could produce heat, electricity and hot water in one single unit, this, at lowest cost and smallest size as possible. So the goal here is to connect a gas generator to a free turbo, this free turbo connected to a reduction gearbox and electrical generator. The "Driven" turbo's compressor will be use to circulate air to extract heat from the (Cool it too) and warm-up an environment, the gas generator will generate heat, the "bearing housing being water cooled will take care of hot water and we are hoping to connect the free turbo to a 10:1 reduction gearbox to rotate an electrical generator, and that's about it.

Overall goal = Heat, electricity, hot water, smallest possible and lower cost possible ... Right now, the equivalent of what we are tryin to achieve is very very heavy, burns gasoline (Not Green) and is very noisy is the low frequency band ... A Generator John ... We are just trying to put together a damn generator ... But instead of only providing electricity, we want to make it a heating unit for both air and water using propane.

Thanks and regards,

[racketmotorman]

Hi Luc

LOL..............a simply little job

I'll think on it .

Cheers
John

[luc]

Lollll ...

Yeappp ... A simply little "Sunday afternoon" job ... LOL

As for the GT2560 issue ... Would you be more happy if i could put my and on two GTX6067R isntead of the 2560?????

Cheers,