Soviet engines with monocrystalline blades

[mandeb48]

I found in Internet (wiki) that engine NK86A has single crystal blades. Somebody knows serious bibliography to confirm? Which another Soviet engine has single crystal blades?

 

[sferrin]

I found in Internet (wiki) that engine NK86 has single crystal blades. Somebody knows serious bibliography to confirm? Which another Soviet engine has single crystal blades?

Single-crystal blades are nothing new. They've been around since at least the early 80s.

 

[mandeb48]

[/size]Single-crystal blades are nothing new. They've been around since at least the early 80s.

thanks for your reply, but I think the Single-crystal blades were not common in the USSR, Could you please specify some soviet engines that use it?

 

[sferrin]

Single-crystal blades are nothing new. They've been around since at least the early 80s.

thanks for your reply, but I think the Single-crystal blades were not common in the USSR, Could you please specify some soviet engines that use it?

I would have thought at least the AL-31 and RD-33 series but I honestly don't know. Like I said, they've been around for sometime.

 

[Artie Bob]

IIRC, the evaluation of the MiG-25 that landed in Japan confirmed its engines had monocrystalline turbine blades.

Artie Bob

 

[overscan (PaulMM)]

Highly doubt that.

AL-31F was designed to use single crystal blades for its turbines, but problems with implementing the process for production meant it was changed over to directionally solidified ones with improved cooling techniques in the early series engines. I expect at some point one of the later series AL-31Fs introduced single crystal blades but don't have specific information.

 

[tartle]

The move from conventionally cast to directionally solidified to single crystal blades is a matter of technique of production which can be influenced by the alloy chosen... I would think that the Russians would know how to but may have had trouble scaling from lab to factory which may account for the delay in rolling out the upgraded blades. Pure speculation on my part... based on how I believe the necessary quality of result was achieved in the UK.

 

[overscan (PaulMM)]

Absolutely right I think - making a few experimental single crystal blades for a prototype engine is not the same as making 1000s of them for a production engine. The separation between OKB and Factory didn't help here - the factories would frequently object to elements of designs given to them on the grounds of difficulty of reliable mass production.

 

[mandeb48]

I never imagined that this information was so hard to find :'(


Something that may help:
http://www.technetium-99.ru/Presentations/Kablov.pdf

http://www.avid.ru/pr/other/aviadv/ib-11a/RI-06.07-20/



I guess the NK-86A engine employs directionally solidified blades and wikipedia confuses the terms in Russian.

 

[gizmo]

I was told that SU27 MKI engines, Al-31FP have monocrystal turbine blades, here is a pic of me holdning what is supposed to be such a blade. Could someone see frrom the pic if it indeed is one?

 

[mandeb48]

I will try to give a brief summary of the technology of Soviet turbine blades. Would appreciate any help to complete the table


Engine alloy technology



ВК-2500 ЖС-26 directionally solidified
ПС-90А ЖС-26 directionally solidified
ПС-90А2 ЖС-36 Single-crystal blades
АИ-222-25 ? directionally solidified
D-30KP ЖС-6U equiaxed structure
D-30F6 ЖС-6U equiaxed structure

 

[tartle]

Gizmo... I have been wondering how to illustrate the differences between conventional, columnar and single crystal structured blading. I can confirm that conventionally cast blading has a surface that looks like crazy paving; columnar structures look like laminated structures running from root to tip; single crystals have a surface with no boundary signs whatsoever... this was confirmed to me when I looked at 3 such blades at the London Science Museum today; I was going to the National Archives at Kew but they shut on Mondays so went to Flight Gallery at SciMus... the blades are on the materials floor though! When I can get the photos I took onto my computer I'll post them here... so tbc!

 

[mandeb48]

I update the list:

Engine alloy technology


ВК-2500 ЖС-26
ПС-90А ЖС-26 directionally solidified
ПС-90А2 ЖС-36 Single-crystal blades
АИ-222-25 ? directionally solidified
D-30KP ЖС-6U equiaxed structure
D-30F6 ЖС-6U equiaxed structure


HP LP
AL31F ЖС-26 directionally solidified ЖС-6U equiaxed structure
RD-33 ЖС-26 directionally solidified ЖС-6U equiaxed structure