For ultra-high-thrust civil turbofan engines, what they need is no longer that the core engine can be used in a variety of types, but more attention is paid to whether the core engine can cope with a wider range of thrust coverage, for example, the entire series of GE-90 engines is based on one engine, and constantly derives engines from 28-58 tons, and the middle span even reaches an unprecedented 30 tons. Pen & Fun & Pavilion www.biquge.info

Serialized engines with such a huge span usually think that they still follow the old routine and make a fuss from the fan aspect of the outer duct, but in fact, no matter how much the fan can make a fuss, it is impossible to meet such a huge thrust span, so what is needed at this time is to put more thought into the design of the core machine.

But when it comes to the design of the core engine of these engines, this time it is really the right person, Jiang Hefu, who has long been eager to try, quickly came up with the technical plan he brought: "For the core engine of the future civil super-large thrust turbofan, because of the large thrust range to be covered by the engine, the core machine I plan is mainly to design the air flow to be relatively large, which will be of great help to the entire engine in the future." ”

For the flow of the core machine, this indicator is not important in fact, but you really want to say that it is important, in fact, it is also very important, and only when the air flow of the core machine is high enough, the engine is likely to do the thrust, if the air flow of the core machine is not good, then the future of the whole engine will not develop much, unless you are really in the low-voltage fan attainments of the dick exploded.

However, sometimes the flow rate of the core machine is not as high as possible, and many times due to the constraints of materials and fluid mechanics, the increase in the flow rate of the core machine is accompanied by a substantial increase in the weight of the core machine, which will naturally cause problems such as high fuel consumption of the core machine, unless you are willing to choose to reduce the output of the core machine.

Then, according to the design plan, Chief Engineer Jiang continued to say the other supporting design: "After the design of the core engine is completed, how to realize the whole series of engines in the case of different thrust in the optimal way, this mainly involves the design of our medium pressure compressor, in fact, the design of the medium compressor is the focus of the whole series of engines to achieve different thrust, we will cooperate with 0112 together, will design three different medium pressure compressors." ”

The so-called three different medium-pressure compressors, of course, correspond to the entire 30-ton, 40-ton, 50-ton three models, with such three types of medium-pressure compressors, and then with the only one high-pressure compressor, so that it is a real core machine.

That's right, this ultra-large thrust turbofan engine series will have three kinds of low, medium and high, in fact, according to the definition of the core machine in a broad sense, it actually refers to the high-pressure compressor plus the combustion chamber of the entire high-temperature section, and this medium-pressure compressor does not meet the requirements of using it in a high-temperature environment, so it cannot be counted in the category of the entire core machine.

It's just that in a sense, in addition to the low-pressure duct part of the civil aviation engine, the other parts can actually be all counted as the core machine, such as pulling on the three-rotor engine, the core machine can be calculated together with the medium pressure compressor in a sense, and the medium pressure compressor does not need to be used under ultra-high temperature conditions, plus its rotation is not too high, and the compression ratio is relatively low, so it will be relatively easy to design. Designing all three medium-pressure compressors together does not require too many resources.

Through the different design of the medium pressure compressor, it is relatively easy to achieve the different thrust of the engine core engine, and such a design scheme can definitely meet the requirements, not to mention that the engine design can have more supporting schemes.

However, the supporting design is definitely not the place of the 624 tube, which Yang Hui is also quite clear, so he gave an affirmation after hearing the design plan this time.

"The design idea is very good, I can roughly understand the situation, you plan to focus on the development of high-pressure compressors and other hot-end components first, and then match different medium-pressure compressors, so as to form three different core machine designs, so that they can correspond to different thrust levels. And if I'm guessing correctly, this time our ultra-thrust turbofan engine uses twin-rotor and gear transmission technology, right? ”

Twin rotors plus gear transmission technology, this is actually the technical route taken by the previous CG-2000 series engines, so it is also considered the heirloom of United Aero Engines, and it is normal to use it on the super-large thrust turbofan this time, but Yang Hui is now thinking about how to overcome the gear reducer technology when the time comes, which will definitely not be less risky than when Rolls-Royce engaged in three rotors.

It's just that the current United Aero Engine Company has accumulated enough experience in gear transmission technology, and now if the United Aero Engine Company says that it occupies the second place in gear transmission technology, then there is absolutely no other aero engine giant dare to call it the first, which is the confidence of United Aero Engine: as the strongest in the entire industry in aero engine gear transmission technology, and since it is the first existence, then even if the problem is difficult, it must be difficult to face the difficulties.

In fact, these worries are not superfluous, although Yang Hui did not say it at this time, but how could Jiang Hefu not know, and directly gave an explanation: "After the core machine composed of medium pressure compressor and high pressure compressor, followed by the technical framework of the outer duct, after I contacted the 0112 Institute, the two sides have discussed the plan for the design of the low-pressure fan, mainly using gear transmission, and adding large and small blade technology." ”

After simply finding a piece of paper, but also drew a simple low-voltage fan section design diagram, after seeing the design ideas, Yang Hui also had to admire the whimsy of these designers, this is simply a match made in heaven, I believe that the large and small blade technology will become the standard design of civil large bypass ratio turbofan engines.

The so-called large and small blade technology is actually to add a shorter small blade to the blade root after the overall assembly of the large fan, and the small blade and the large blade are arranged at intervals, and the problem to be solved by these small blades is the low compression efficiency at the blade root caused by various mechanical trade-offs of the large fan blade. (To be continued.) )