LPS 130 Turboprop / Powershaft

athome

athome

Hi all
Sorry that I'm writing in English.
I'm on the way of finishing my DIY LPS130 Turboprop / Power shaft. I built an 2nd stage for the gas generator which is based on the GR130 of Gerald Rutten. I will use it for a big helicopter project which i going to start if the turbine runs well. So it’s a long term project. More details you can find on my homepage: here the Gasgenerator:
http://www.turbinenheli.ch/eigenbau-turbine/1-stufe-gasgenerator/index.html

and the second stage

http://www.turbinenheli.ch/eigenbau-turbine/2-stufe-wellenturbine/index.html

It’s in German but with google translator, hopefully you will be able to read it :)
Before I connect this both stages together, I did several further tests with the Gasgenerator. And as more as I got a better sealing I got more surging!
So I had contact with Gerald and decided to change to a new compressor diffusor with steeper and flatter angles. So for now I’ve finished these both diffusors one with 10° and one with 12°. For the first test, I used the 12° …. But surging is still there. Before with the original 11° diffusor I had surging most during the acceleration between 40 and 60K and now with the 12° it’s almost the same maybe it’s a little bit higher…but I think it’s hard to figured that out (depends on weather and air pressure)

So before I start rebuilding to the 10° I thought I will ask you guy….
I think the surging happens in the combustion chamaber….

So that’s it for now :)

Regards Lukacs and thanks for your thoughts
 
So weeks are gone and I have no Idea anymore. I’ve tried compressor diffusor with angles of 12° and with 10° (Original 11°). I’ve rebuild the whole Kero injection rings…and a lot more.
I always have the same. My turbine goes of during the calibration run around 50 to 60k RPM with a big roaring before (probably surging)!
I think more and more It’s a chamber problem….

I’ve built a logger Soft- and Hardware where you can see what happens.

Does anybody have an idea?
In rarely times I get it to run…and then there is no problem at all incl. Running up to 90K RPM (most when it’s warm outside… over 25°)

Thanks Lukacs
 

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I think
you have a ball bearing problem.
The bearings are not in line.
or ball bearing can not slide or search.
the spring should not be too heavy.
I have better experience. with a compression spring. with a low pressure
 
Hey thank you for your thoughts! You may really be right. The alignment is perfect, but I think because it’s just an aluminum tunnel the expansion is too much and because I only use waver springs there is not enough travel. Wow good idea. I will, like I have done on the second stage, going to build a V2A tunnel.
regards Lukacs
 
@ Franky danke vielmal. In der Zwischenzeit bin ich weiter, leider ist die Webseite noch nicht auf dem neusten Stand. Das neuste ist die komplette Turbinen Überwachung und das Starten der Turbine mit eigener Hardware und Software

@ G J Broekhuizen for a quick fix I've lowerd the pressure of the waver spring. Will try a start today!

Regards Lukacs
 
Eine frage über deine gebrauchte feder.
Ist dass nicht besser um eine belleville-tellerfeder zu gebrauchen?
Die belleville-tellerfeder haben rundum contact mit eine kugellager. Eine well-tellerfeder hatte auf 3 punkten contact. Ist damit nicht möglich dass ein well-tellerfeder diene kugellager schief drucken will?
 
Once more no success!!! But it’s spinning longer with the lowered tension. So this is not the problem!
Strange....weeks and months before I had to fight with surging, now I have to fight with the calibration not going through....It always stops with big white smoke, most of the time when the ECU calls Idle again (after it reaches the 60K RPM) or sometimes also during the acceleration…Every parameter is on the slow and easy running side. The ECU is resetted and all parameters are reentered...

I cannot understand it, because after finishing a few years ago it runs without troubles... And suddenly more and more surging happened... and it always getting worse.
I’m so frustrated….I would just like to have it running, that I can apply the second stage which is finish now…..

Lukacs
 
Hey Franky
berechtigte Frage. Viele Turbinenbauer haben es schon so gemacht z.b. Gerald. Ich habe es einfach übernommen.
 
upload_2017-4-20_21-35-58.png



This log is also interesting.

Declaration of Status:
11 --> Calibrate
18 --> Wait ACC
13 --> Steady
9 --> slow down

During the "Steady" Phase the temperature goes off... Looks like it's getting blown out
 
upload_2017-4-23_17-39-39.png



Here you see fantastic the surging! did a lot more tests now.it goes off because of Flame out! No hotspot. Temperatur more or less OK….
So I have definitely to change something on the combustion chamber… Where should I enlarge the holes. Temperature

Thanks for your help!
Lukacs
 
Just found a mail from Gerald :). Here his answer:
You can also try to increase combustionchamber air holes, making it less restrictive. You could try to start with the rear large cooling holes, increasing them with 0,5 to 1mm and see what happens. There are sooo many variables to work on though
That's what I will going to try...
Regards Lukacs
 
The RPM is a bit low for surging... How does the flame look when the issue starts? All yellow or blue already?
 
Hey guys
Thank you for your thoughts and help.
Yesterday evening, I increased the holes in the back from 5.0 mm to 5.2 mm so there is enlargement (calculated from the area) of almost 2 more holes. I also shifted the compressor inlet 6/10mm away from the compressor! Today a new try!
And it runs!!!
Still some deep humming around 55000 RPM….but it was stable!
Attached the log! You can see the fast acceleration/deceleration, when it runs!
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Regards Lukacs
 

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Blue flames indicate there is enough air / oxygen in mixed in with the fuel so opening the rear holes is an option, as you already did.

But this is a engine without load right? The low temperatures look good without load but you should check them with a stable rpm :)

You moved the compressor away from the inlet? Then you are making the compressor less efficient. You lower the airflow and therefor the remove the compressor stall. You did check there was no contact between then compressor and the inlet? You can get lower temperatures with the old position, i expect them to fall just below 500 idle.
 
Hey Tadango,
Yes will going to open the rear holes more.The temperature is for me to hot…
Yes the engine is a gas generator …and yes it has no load at the moment. The second stage would be ready if the gas generator would run stable…
No I moved the inlet (or how is it called) away from the compressor :) . Exactly! The idea is to lower the airflow and therefor the stall (and as you could see from my logs. It worked).
Yes no contact between inlet and Compressor…

Will try to make the holes once more bigger…once more 2/10mm
Lukacs
 
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