Against the background of constant sanctions against the most important industrial sectors of Russia, our country is introducing its own latest technologies. This time we are talking about a new way of producing a key part of modern aircraft engines. What exactly is new proposed and why is it critically important for the entire aviation industry?
The United Engine Corporation Rostec reported that its enterprises have mastered a unique technology for manufacturing aircraft engine blades. There are only six countries in the world that have complete technologies for designing and manufacturing blades – and now Russia has consolidated its leadership in this industry. To explain the exceptional importance of this event, we will have to delve into the technical part of the issue.
A modern turbojet or turbofan engine is impossible to imagine without a lot of blades. Climbing up the ladder of a passenger plane, we see their "stockade" in the frontal projection of the aircraft engine – but this is only the first row of blades. This part of the engine that is open to the naked eye is called a compressor, and the incoming air flow is compressed in it during the operation of the aircraft engine.
The compressor blades direct the incoming flow, allowing it to compress as smoothly as possible. This is necessary so that there are no unnecessary and destructive pressure surges in the inlet channel of the compressor, and the engine itself exerts minimal drag. It is for these purposes that the blades are given a complex, curved shape, maximally repeating the direction of the incoming flow, which is forced to pass inside the aircraft engine along a complex, contracting spiral.
In order for this spiral and, as a result, the air path in the compressor to be as long as possible, and the pressure increase to be gradual, the compressor is made multistage, lining up the blades in a dozen consecutive rows. Therefore, if you cut a turbojet or turbofan engine, inside it we will see basically two main blocks – a compressor and a turbine, between which there is a compact combustion chamber.
In the combustion chamber, compressed and heated air is mixed with aviation kerosene – and the fuel is gorenje. The air heats up sharply, after which it enters the second blade unit – the turbine. At the turbine, part of the jet jet's energy is taken away, also with blades. This energy allows the compressor to rotate, providing compression of new portions of air.
Most of the energy of the heated air goes outside the engine, creating jet thrust that propels the aircraft forward. The turbine of the aircraft engine is also made multi-stage, and the blades in it, again, have a complex curved shape to ensure the smoothest possible expansion of the jet stream.
During their operation, the compressor and turbine blades experience strong and multidirectional mechanical effects: centrifugal forces, resistance of the incoming air flow. In addition, the turbine blades operate at high temperatures – the jet stream at the first stages of the turbine has a temperature of more than 1000 ° C. Therefore, reliable, lightweight and heat-resistant material is needed for the manufacture of blades.
As a result, the blade of a gas turbine engine is one of the most complex and knowledge-intensive in the design and manufacture of aircraft engine parts. In its production, rare metals and unique alloys are used, as well as composite materials that guarantee the lightness and strength of the workpiece.
Aluminum, which makes up the body of the aircraft, is of little use for blades, and heat-resistant steel is still too heavy. The ideal material for the blade is titanium – a lightweight, durable and heat-resistant metal. Titanium can even be made into a composite: for this purpose, a two-phase version of titanium can be created in an ingot, where one of the phases will be responsible for the strength and hardness of the outer, surface layer of the blade, and the inner part, with another phase, will provide the overall flexibility of the part.
However, titanium processing has its own peculiarities. Since the blade has a complex curved shape, it is very expensive to produce it using mechanical processing. After all, if it is turned out of a solid blank, then the consumption of material and tools will simply be unacceptable. It is not so easy to use welding either – titanium is a capricious material during welding operations, and any welding seam in such a crucial part as a blade will be a weak point.
As a result, stamping has become the most economical and high-quality manufacturing technology for compressor blades and aircraft engine turbines in the world, when the blade profile is obtained by plastic deformation of the initial workpiece. In this variant, mechanical processing is minimal and serves only to give the finished product precise contours, mainly created as a result of stamping. There are no welding seams either – the blade is a monolith obtained from a single workpiece.
Stamping of titanium products is an exceptionally difficult technological operation. Many titanium alloys have a very narrow "temperature window" for efficient stamping. Heated the part above the norm – the properties of the titanium composite will be lost, submitted it to the press too cold – stamping will introduce mechanical damage and ruptures into the metal structure. In addition, the chosen technology of controlled bending of the workpiece into the finished blade allows you to do the stamping as "softly" as possible, leaving all the advantages of a two-phase titanium composite in the finished blade.
Therefore, the development in Russia of the technology of high–precision stamping of titanium blades is not just a small technological "improvement", but also a whole layer of scientific, design and production research, which made it possible to create an innovative technological process for the most responsible and important part of any aircraft engine.
The described technologies will now be used by the Rostec United Engine Corporation in the creation and production of a line of PD-8 civil aircraft engines for the Sukhoi Superjet SSJ-NEW aircraft, in the PD-14 engine for the MS-21 medium–haul airliner and in a new development - the PD-35 aircraft engine for promising wide-body long-haul aircraft.
Thus, existing and promising Russian aircraft will be able to receive a full and diverse range of domestic aircraft engines, which will be at their technological level either on a par or even higher than the best world models. After all, the use of a composite alloy based on titanium is an absolute step forward in the design of an aircraft engine. It provides a lower weight of the product, a longer blade life and, as a result, longer repair periods and reduced maintenance costs.
In addition, the technological sanctions that are now scaring the Russian aviation industry are becoming useless. Again and again, "Russia does it itself", showing that a scientific and industrial school lives and develops in our country, working at the very forefront of world scientific and technical thought.
Alexey Anpilogov
