Hello

Is it possible to construct a steam turbine out of a turbo charger from a lorry? If possible it would give me a nice project after my GCSE's.

Thank you

Quite possibly but you would need a lot of steam.

There has been discussion of the use of turbochargers as exhaust steam turbines to increase the efficiency of reciprocating steam engines on the forum of the Steam Automobile Club of America. [www.steamautomobile.com]

Also look at the thread on BMW steam engine on this site.

Mike

Oliver,

What size is that turbocharger?

A turbine for steam automobile use would need a variable nozzle system of some kind, either a variable nozzle ring or variable size nozzles. Many of the medium sized turbocharger turbines reclaim upwards of 35 Hp and use it to run the compressor stage. A turbine by it'self isn't well suited to an automobile as there is an RPM range that it works best at. Coupled with a piston engine, however, there are some definite possibilities.

One of the design dificulties is to get the correct reduction gearing and a slush box. As I understand it a piston engine changes RPMs too fast for the turbine to keep in step without some severe stresses so a slush box is nesseccary.

Good Day ----------- Bill G.

Is your steam lorry turbo a Stone?
I experiment with turbocharger based steam turbines in the US.
Just don't know that much about Bristish lorries.

Speed change on piston compound is correct.
The major problem ran into with pilots not used to turbines was excessive speed
throttle position changes.American Airlines have to scrap all their piston engines because of that maintenace item.The 3350 compund were good for gradual changes ,but didn't "firewall or chop"the throttle.It would overaccelarate or cook the turbine....usually cook.Overacceleration put excessive G-force loads
on the turbine wheel.Since strech from the g-force loads is much of what normal wear on a turbine is about....you might say woreout extra fast.

Arnold,

The more I look at the turbine section of my compound the bigger a consideration and higher proportion of the power output it is becomming. As I mentioned previously on the Steam Stuff Phorum it is running on a Joule cycle with the piston engine doing the compressing.

At full output of 200 HP from the piston engine the turbine will be adding another 100 HP, much more than I had previously figured. This requires a turbine output of about 200 Hp as roughly half the output goes back into recompression.

I would think that this size of turbine is starting to leave the realm of common turbocharger turbines and possibly radial inflow blading, but don't know for sure.

Any thoughts on how to couple piston engine and turbine together. Reversing nozzels? Also many turbochargers run happily at around 1700 deg input but I have heard of up to 2200 deg. This is a major difference in efficiency from 1700 to 2200, what's the highest non experimental temperatures you are aware of?

For those unaware of what I am shooting for, this is a design for a high efficiency truck engine and later a rather fast motorcycle.

Thank You ------------ Bill G.

A Garrett t100 is about as large as you are going to find in a truck junkyard.
It is only good for 100hp.
How many pounds of steam is your piston engine exhausting.
In simple expansion to a condenser on a 250hp Coppus or Terry is 7800 lbs roughly.
With my odd version of reheating on the turbine......you can chop that flow to
1950 pounds per hr.

Come to think if it. What is the piston engine max rpm...got a gearbox worked up to directdrive at 800rpm on the output shaft.(non reversing,so you would have to bypass turbine when you reverve the piston engine.)

Hi Arnold,

Do you know the maximum working temperature of the big garrett?

The turbine will be running off of the engines compressors which will be compressing saturated steam from roughly 20 to 100 psia. They are about 600 cubic inchs and the design RPM of the engine is 1800. If I can get the weight of the second stage pistons down farther then higher RPMs might be obtained.

The second stage of the compound expands right down into the wet steam area and to the condensers pressure. The pistons are double acting with the top ends forming the compressors. The turbines cycle is independent from the piston engines Rankine cycle.

Due to the timing between stages the engine does not reverse. I don't think reversing is neccessary with the need for a neutral, park, and 2nd gear adding a reverse to a transmission is no biggie. Remember that the speeds a modern vehicle travels are much higher than the older cars and there is better fuel mileage when the engine is loafing along in high gear.

The engines efficiency calculates to just plain scary so awaiting the day something can be put to the dyno. So many things have to come together to make this happen. So far no hitches in the design part other than getting the information in a timely fashion. It's a different beast.

Thank You ----------- Bill G.

Past 100hp on the turbochargers. You would be looking in shipyards,railroad locomotive junk bins,electric utility diesel generator parts bins. For turbochargers that large.

Small gas turbine which have a better Pressure Ratio and are radial inflow. Are a horse of another color.
The Brits have a few surplus Rover 2S at places like Everett Aero.
The Americans have Solar T62-32 and Garrett GTP70 in surplus at places like
Avon Aero.
All of them are setup to run about 60psi and 160hp shaft horses at 6000rpms.
(Compressor horse requirements already included on gas turbine)
Don't like the reliably of the Garrett JFS100 like the Brit Solent was only for short starter motor duty.And both had service life problems doing that.....

PR ratio on turbochargers are usually about 3 at best.
The gas turbines listed above can hit 5.....though they operate at 4 PR,roughly.

Though the flow thru the gas turbine is 7800lbs/hr....it is only using 15% to25% of that from the piston steam engine.(self recompressing and recirculating with a steam trap to strip the water.)

Oh,max temperature.....both radial inflow gas turbine and turbochargers average
about 1800F. between the makes and models out there.
200hp from the piston steam plus 160hp from the turbine.....sounds like a heavy truck running 360 horsepower.

International diesel rigs upshift at 2200rpm's
Frieghtliners and Volvo's upshift at1850 rpm's
Petebuilt's upshift at 1500rpm's
Sounds like your steam idea is near the same speed as a heavy diesel truck would use.
With existing drivetrains.300 to 450 hp. is the number. Most of highway trucks roll.
Odd ball guys like the coal haulers in Utah with 135,000 pound (gross) trucks. They run about 550-750hp on a triple trailer trucks criusing at 70 to 80mph thru the foothills.(You start having quick throttle movements breaking driveshafts at 650hp.)

Arnold,

Thanks for the information. Getting passed by one of those big rigs while in a small car is an experience.

Dropping down to 80 psia to get the 4/1 pressure ratio does run a lot of steam around in a circle for the power output. Do you think there may be an advantage to bumping the pressure up to say 110 psia and using two turbines in series at a 2.34/1 PR each? Then maybe one could be cut out for cruising.

How does that self recirculating turbine work? It sounds like you have looked that one over pretty good? Replacing the combustor with a steam generator and running the turbine on steam spawns some interesting ideas. Especially when coupled to an engine like mine.

Best ------------- Bill G.