kvs wrote:I found the comment about some derivative being used for the An-124 a bit strange and people here have filled in the details. The D-18T does not resemble
the NK-32 in any fashion and any replacement for it would be starting from scratch. The PD-35 is supposed be based on a scalable design and would be
a high bypass turbofan so it make sense to use it instead of an NK-32 derivative.
The An-124 (and probably also the new il-106) needs an engine with about 23-24 tons of takeoff thrust (but it could benefits of a bit more thrust, and in the past motor sich proposed a D18T modification with 25-26 tons of takeoff thrust).
The PD35 will not be ready before at least 6 years and even if it is a scalable design the PD24 will be less of a priority, and will be available later. (They need anyway to design and test a new engine, even if they could save a bit of time by reusing the solutions from its smaller (PD14) and bigger brother PD35).
Concerning the NK32 derived engine, as it was mentioned in another thread, it should be in development already since several years ago and a variant of it should go on the Pak-Da subsonic bomber).
In a few articles from last year and from early 2020 also it was mentioned that such engine should start ground tests around the last quarter of 2020...
Another NK32 derived engine, called NK-23D should also be in development (or was proposed) and it is not clear how much commonality there is between this one and the Pak-Da engine.
It wouldn't need to be started from scratch anyway.
At least, not the whole of the engine...
Well, if the core (in this case IP and HP compressor, Combustor, and HP and IP turbine) is of the acceptable size, they need to probably upgrade a bit the materials and some minor redesign (to get some increase of operating temperatures for the HP compressor and turbine) and probably some changes to the combustor as well.
A few stages must be added to the LP turbine (since it operates at a lower speed, having a bigger fan, and maybe also there they could introduce some new lighter materials (like intermetallic ti-al for LP turbine blades, probably already considered also for PD14 and PD35).
The fan needs of course to be completely new, going from a multi stage very low bypass fan (needed for supersonic speed) of the NK32 to a large single stage fan (maybe a scaled up version of the PD14 fan, if perm motors and Kutznetov exchange information)...
The only strange information (dated 2015) available in internet mentioned that, since they wanted to keep the same nacelle of the D18T, they will end up compromising the design and limiting the Bypass to a value of about 5,5 to1, the same as the old D18T, and with a specific fuel consumption slightly worse than the old D18T... but that does not make sense...unless we are talking about a solution that can be ready in a relatively short time and it is just a placeholder...
https://www.litmir.me/br/?b=547394&p=9
Anton Shatskiy, Deputy General Designer of OJSC Kuznetsov, said at a conference at CIAM that a unique turbine that can withstand long-term high-temperature conditions provides the NK-32 gas generator with a parametric and design reserve for creating a line of high-thrust turbojet engines on its basis for use on transport and passenger aircraft. The first in their series could be the NK-23D three-shaft by-pass turbojet engine with a thrust of 24 tf for the remotorization of the An-124 Ruslan heavy military transport aircraft.
According to Anton Shatskiy, “the task is to raise the An-124 aircraft with domestic engines in 2019,” but “if we are now talking about creating a scientific and technical reserve, carrying out research and development work,” then the creation of a new engine of this class may take 10 -15 years. Therefore, Kuznetsov offers an alternative solution - to make an engine for Ruslan with the maximum use of the already existing reserve for the NK-32 gas generator. At the same time, serious conditions are set for the engine specialists: “We must fit exactly into the dimensions of the D-18T nacelle, the nacelle must remain in the same length, approximately in the same mass, i.e. we have both geometric and constructive constraints, ”said Kuznetsov’s deputy general designer. Nevertheless, he believes that it is quite possible to meet such a tight deadline.
According to the presentation presented at the conference in CIAM, the NK-23D proposed for remotorization of Ruslans with a takeoff thrust of 24 tf (for the D-18T - 23.4 tf) will have a degree in cruise mode (height 11 km, M = 0.75) bypass 5.4 (for D-18T - 5.5) and specific fuel consumption 0.565 kg / (kgf • h) with a thrust of 5000 kgf. According to the official data of Motor Sich PJSC, the thrust and specific fuel consumption of the D-18T series 3 in cruising mode in the same conditions is 4860 kgf and 0.546 kg / (kgf • h).
Here it is not clear if this engine (NK23D) will be related to the similar thrust engine in development for the Pak-Da or not....
It would be smarter to redesign the nacelle and allow the advantages of a higher bypass... in that case however this will mean that it will not be able to mount them in the existing an124 withoout modifying the pylons and the mounts as well...
By the way, if I am not mistaken Kuznetov has in the not so remote past, already did a comparable operation (but smaller in scale), when they improved the D30 engine with a bigger fan to increase a bit the bypass.
Home
Latest images
Register
Log in
(unfortunately in Russian but still their is plenty for mono-lingual types like me).
Rodion_Romanovic