Pratt & Whitney PW1000G | A320 NEO - Airbus A320 New Engine Option

Im i blind or why can't i see any stator-vanes in the PW-1000 picture linked above?

Yes - it can be that i do not have sufficent knoweledge or correct tools to make a good jet engine this however does not matter so much for me. It will be a fun project anyway.

The only way to get rid of the stators would be to use alternate counterrotating rotors....
Unfortunately that would require the same number of shafts as rotors, but as the cross section gets smaller with each stage, there would be enough space for a shaft in shaft in shaft in shaft .... design.
This would allow for a suprisingly short housing.
(and probably for a surprisingly short life as well)

Good luck, and stay away from the path of the high speed debris.

As I recall, had a set of plans to build a simple ‘jet’ engine using an old car turbocharger. Here is a link to one of MANY on youtube.
No stators.

It's a Cut-a-way

They jusy just cut-a-way the stators in the drawing

amazing what one can do in this new fangled digital cad-cam age

For a pure tubojet with statorless counter rotating adjacent rotors I wonder how they will react out the postitive thrust component to push the plane

Pratt & Whitney PW1000G | A320 NEO - Airbus A320 New Engine Option

N1 is geared, contra LPT. The other three sections all contra rotate, in trail.

A conventional propeller may be thought of a single-stage compressor rotor sans stator. If you were to conduct a tuft test, of a smoke-stream test, you'd find the slipstream is a vortex about the propeller-shaft axis. This vortex represents energy (static pressure) losses that can readily be recovered with either a stator assembly, or with a contra-rotating prop system.

But worse, if you tried to put a second prop in series, behind the first prop and turning the same direction, it would have difficulty achieving a similar pressure rise, because of the poor match (low alpha) between the airflow vector and the second prop blade angle. This is the situation you face in a statorless axial compressor.

Don't forget that steel may not melt before it reaches 1400 degrees C, but most ordinary alloys will be pretty soft and oxidize rather quickly at 900 degrees.

The PW1000.

No stators shown. In this cutaway.

Imagine the engine as it is, and then somehow turn it over to around 5000 PM, the add ignition and fuel.....whats going to happen?

Fuel will be added to an ambient pressure airflow and burn a bit like a blow torch, for a while.

After the starting source is gone, the engine will not produce the airflow to turn the turbine..efficiently enough to self sustain. It will wind down to zero RPM.

The air has to be compressed.

PW1000

Like a stuck record - its a cutaway. If you look closely you can see the gaps where the stator stage or blisk would sit

Dog Driver - car turbo chargers use centrifugal compressors (and centripetal turbines ) They do not use stator vanes - the equivalent on this type of compressor is diffuser vanes. On the exit from the rotating section they guide the flow through divergent passages slowing the airflow and increasing the pressure.

Volume - I am at a loss as to how you would drive contra-rotating stages on two concentric shafts - I am not saying it cannot be done it is just that I cannot work out how to do it with more than one stage.

I am a retired line maintenance engineer -qualified on RR,GE and P+W big fan engines and this thread has made me get out the books and go back to first principles,trying to bring back stuff that I was taught 30 - 40 years ago and have enjoyed it very much -keeping the brain active! I hope our friend can overcome all the difficulties and get his engine to run and keep us informed as to progress.If he runs into problems I am sure there is enough knowledge both practical and theoretical on Pprune to advise him. Once again I advise him to obtain a copy of the Rolls-Royce publication 'The Jet Engine' there is no better book available that I know of that can give such an insight into the construction and principles of operation of gas turbine powerplants.

Best of luck rpetersson :ok:

CNC machines were way out of our reach when I was having ideas like that. Rather than re-invent the wheel why don't you try doing something that has never done before (everything's been done before) with building a jet engine.

Here are some ideas, and I'm not promissing they are any good.
1) Forward swept axial flow compressor blades. Look cool too.
2) Outer rim air bearing. To prevent tip path losses the blade tip is connected solidly or cast to an outer rim which has tiny holes in it to let air pass through from centripital forces and form a boundary layer of air to act as a lubricant.

A friend of mine (ex aircraft engine maintenance engineer) who is now in the auto turbocharger reconditioning business told me a story about a buch of visiting scientists who in a laboratory were 'growing' turbine blades one crystal layer at a time and were looking for a machine that could balance their spining fan at 200,000 rpm. Incredible stuff.

Have fun.

Single crystal turbine blades have been in use for at least 20 years in production gas turbine engines

bcgallacher

Just for ducks. Stators are used to keep the gaspath in an axial flow turbojet.....erm.....axial.

Without, the gaspath develops the familiar vortex. With that in mind, this vortex is bound by the engine's case, and can be described as a "helix". Which is simply a vortex with cylindrical shape, bound.

What purpose can the energy thus acquired be harnessd to do. What design change relative to the geometry of the gaspath would be required to hybridize this engine as a partial "Centrifugal/Axial" engine.

There are axial/centrifugal flow engines around - the old Bristol Proteus was one such and I think some of the smaller French engines.The axial stages are in front of a final centrifugal stage - about the only advantage I can see is that the engine can be built shorter. Centrifugal compressors are very robust - I worked for about 13 years with RR Dart engines and never saw one pulled for compressor damage but have seen many axial flow engines with sometimes extreme damage from bird ingestion. FOD and even damage due to surge and stall. Centrifugal compressors work over a larger rpm range although they run at higher rpm -up to 15000rpm on RR Dart and a whopping 42000 rpm on the Garrett TPE 331. They do not need airflow control devices such as bleed valves or VGVs. An axial flow engine without stators would not work - you need both to get compression.

Thats the second time in this thread I've seen "high" RPM mentioned. Actually when it comes to aero it's more a case of sonic velocity boundaries (tip dia being as important as RPM).

Not to forget the ubiquitous Pratt & Whitney JT15D, which is also an axial / centrifugal design.

Animation
 

The GEnx Theatre

GE aviation web site. Click on compressor and it will show an animation of an axial compressor turning, stator vanes included.

rpetersson. The best of luck with your project. Stay safe.