Reborn Tech Scholar

Chapter 184 Technical Assembly (810)

Chapter 185 Technical Conference (8/10)

The principle of the turbine of an aero-engine is very similar to that of a car's turbo-increase engine, which uses exhaust and fluid to impinge on the impeller to rotate to generate power.

Whether it is the air flow brought by high-speed flight, or the high temperature and high pressure generated by the combustion chamber, the purpose is to increase the exhaust velocity to allow the turbine to achieve high-intensity operation.

For the turbine of an aero engine, the most critical technology is the blade material, and the turbine blade is also one of the three high-pressure components of an aero engine.

Turbine blades will provide huge power at the cost of bearing high temperatures far exceeding the melting temperature of their metals and centrifugal tensile stresses exceeding [-] Newtons. high strength.

"We all know that under the premise of the same design level of the engine turbine and fan, every time the temperature in front of the turbine increases by 100K, the thrust will increase by about 15.00%!" Academician Liu said: "However, high temperature resistance and high pressure resistance are our limitations! "

"High temperature is the first hurdle for turbine blades. The temperature fluctuates by one or two thousand degrees, or even higher. High-efficiency blades cannot be designed to be solid. Hundreds of thousands of cold air passages need to be printed on one blade!" Liu The academician said seriously: "This will have very high requirements on the strength of the material. The engine developed now, the material limitation is not only the power, but also the lifespan."

"At present, the level of Jingcheng Aeronautical Materials Research Institute in the industry has undoubtedly reached the first..." Academician Liu introduced the latest achievements in turbine blade materials, and the ones under development that may make breakthroughs in the past two to three years.

Beijing Institute of Aeronautical Materials, established in 1956, can be said to have a long history and profound heritage.It has 22 research laboratories including the Key Laboratory of National Defense Science and Technology of Advanced Composite Materials, 2 experimental processing plants, 13 pilot production lines and more than 20 joint ventures. It is a large-scale research center with complete specialties, advanced equipment and instruments, and intensive knowledge hospital.It has nearly 3000 employees, more than half of whom are scientific and technical personnel, and the research institute also has a postgraduate department, which has the right to confer doctoral and master's degrees.

The Beijing Institute of Aeronautical Materials has achieved more than 2000 scientific research achievements so far, including more than 600 major achievements above the ministerial level, and more than 150 national natural science awards, invention awards, and scientific and technological progress awards, which can be said to represent the highest in China's composite materials. level.

Every year at the Science and Technology Conference, the Invention Award and the Science and Technology Progress Award are always indispensable to the Beijing Institute of Aeronautical Materials.

After Academician Liu finished speaking, Qin Yuanqing said: "From the situation you just introduced, the DD2, DD3, DD4 and other D-series high-temperature-resistant materials of the Jingcheng Aeronautical Materials Research Institute are all in the direction of single-crystal nickel. Crystallization is an advantageous method, but it is only a method."

Then Qin Yuanqing handed over the formula to Academician Liu for verification.

Now the research institute can't carry out this level of verification, but Qin Yuanqing can handle it with Academician Liu's connections.

Although Academician Liu felt that this matter was nonsense, if a random formula could solve it, how could those people who work on materials be so worried that their heads would be bald.

But Qin Yuanqing is the dean, and now the research institute has money, so it's just a cost of trial and error anyway.

Watching Academician Liu leave, Qin Yuanqing continued to aim at the fan of the engine: "The fan of the aero-engine this time adopts a three-stage fan design, and the first-stage fan blade adopts a wide-chord and hollow design, which is similar to the Pw3 used for the Boeing 1. The hollow blades used by the engine have the same structure, that is, the blades are connected by two plates of the blade pot and the back of the blade to form a whole blade through the diffusion connection method. Cavity... The three-stage fan rotor made of titanium alloy adopts the overall blisk structure, and the overall blisk is processed by linear friction welding!" Qin Yuanqing said to the fan design team.

Linear friction welding, is a solid state joining technique similar to diffusion joining.Diffusion connection is to close the connection surfaces of two parts to be connected. Under high temperature and high pressure, the mutual transfer of material atoms is formed between the mating surfaces of the two parts, and finally the two parts are tightly connected into one.In this connection, since the material at the joint is not melted, there will be no desoldering phenomenon that is easy to occur in general welding.From a structural point of view, there is no "weld" at the connection, and its strength and elasticity are superior to those of the body material.The difference between linear friction welding and diffusion bonding is that in diffusion bonding, the connected workpiece is heated in a furnace to reach a high temperature; while in linear friction welding, the high temperature of the workpiece is achieved through the mutual high frequency between the two mating surfaces. produced by oscillation.

The person in charge of the fan design office is Academician Bai. Academician Bai is 60 years old this year and has been engaged in the design of aero-engine fans. The more he looked at the fan design drawing Qin Yuanqing made, the more he frowned.

He found that Qin Yuanqing's fan design was quite different from the Kunlun engine and Taihang engine.For example, variable camber inlet guide vanes are used at the inlet of the fan, and the third-stage stator adopts a curved design.

"Academician Bai, I will leave the design optimization in this area to you!" Qin Yuanqing looked at Academician Bai.

Some things are like this, new things, the older generation will find it difficult to accept, but it doesn't matter if it is difficult to accept, as long as you verify it carefully and understand it deeply, you will be able to taste the benefits.

For example, this curved stator blade can improve the efficiency and surge margin of the fan and compressor.

Of course, Qin Yuanqing also knows that although the F119 is the world's most advanced aero engine, it is not a perfect engine, so he did not emphasize that none of them can be modified, as long as there is a way to optimize it, then optimize it.

The better the performance of this kind of thing, the better.

"Okay, leave this to me!" Academician Bai nodded and said.

Although at the level of an academician, you don't need to be a bird to anyone, but Academician Bai still admires Qin Yuanqing because of his courage. It has improved a lot in the past.

Although it is said that the life of an academician is not worrying, and there is no shortage of money.But whoever has no children, who has no relatives, can raise wages, who would not be happy.

Moreover, they have their own students. They had no way to squeeze their own students before. After all, they had no money, and scientific research funds were calculated by points. They wanted to use one dollar as two dollars.

Now that the wages of students are high, they are also happy to be teachers.

Now, in the eyes of many people in Shuimu University, Qin Yuanqing is just a mobile bank with no humanity. Everyone wants Qin Yuanqing to be the dean of their school. How comfortable it is.

However, this also put a lot of pressure on many deans, forcing the deans to go to the company to obtain scientific research funding sponsorship, so as to improve the treatment of the subordinates.Otherwise, people's hearts will be scattered, and the team will not be easy to lead.

Qin Yuanqing watched Academician Bai leave, and estimated that with the strength of their laboratory, it would take at least three to five months to fully understand the information. As for the creation of samples, it must be next year.

Aeroengine technology is different from other technologies. It is a national treasure in any country. Even the United States hides it from its allies in this respect. Do research.

It is because no other country has the F119 aero engine, so that although it is known that it is advanced, no country can imitate it.

If it can be obtained, with the strength of the bear and the rabbit, it is estimated that an engine with similar performance can be imitated within a few years.

Next is the high-pressure compressor. The high-pressure compressor of the F119 adopts a high-grade pressure ratio design, and all 6-stage rotors adopt an integral blisk structure.The front receiver uses "Alloy c" flame-retardant titanium alloy to reduce weight.The stator blades are also curved.In order to increase the longitudinal rigidity of the casing at the outlet of the high-pressure compressor (where the diameter is the smallest, forming a waist), the casing of the combustion chamber extends forward to the third stage of the compressor, so that the rear casing of the compressor has a double-layer structure. The inner layer only acts as a containment ring for the airflow, and this structure is widely used in large, high bypass ratio turbofan engines.

Therefore, for the high-pressure compressor research laboratory, it is relatively easy to understand the technology in this area. After all, Huaxia also has accumulated technology in this area, and now it is just improving and optimizing the original technology.

This kind of thing is like a layer of paper. Once the layer of paper is pierced, you can see another world.

Of course, in the final analysis, it is the "Alloy c" flame-retardant titanium alloy material, but the material information on this aspect has been handed over to Academician Liu.

As for the combustion chamber, it is the most important thing, it can be said that it is still above the material.The combustion chamber is the internal power supply part of the turbine engine, which can be said to be the heart of the turbine engine.

There are several types of aviation turbine engines, namely turboprop engine, turbojet engine and turbofan engine. Among them, the turbojet engine with the highest performance can be loaded on a fighter plane and can easily provide supersonic power. The highest power can make the fighter plane The speed exceeds Mach [-], which is three times the speed of sound.

However, the fuel consumption of a turbojet engine is very high, and the higher the power provided by the engine, the better, and many other issues such as practicality, fuel consumption, and battery life must also be considered.

The speed of a fighter plane can reach Mach [-], but every flight causes a lot of fuel consumption. Not only does it consume a lot of fuel, but high consumption must correspond to low battery life, and the maximum flight distance will be severely limited.

That's why there are turboprop engines and turbofan engines.

A turboprop engine can be understood as a turbojet engine with a propeller in front of it. The engine is dominated by the pulling force (thrust) generated by the propeller. The thrust generated by the jet is very small, accounting for only about one-ninth of the propeller. The advantage is high efficiency at low speed, suitable for transport aircraft, maritime patrol aircraft, etc. Due to the large rotating area of ​​the propeller, it will generate a lot of resistance when flying at high speed, so the turboprop engine is not suitable for high-speed flight.

The turbofan engine is between the turbojet engine and the turboprop engine. It can be understood that a fan is installed in front of the turbojet engine. It can provide good power and can support a speed of 1000 kilometers per hour. The disadvantage of fuel consumption is that the engine structure design and technology are too complicated.

(End of this chapter)