Rebirth of science and technology academic master

Chapter 184 Technology Conference (810)

Chapter 185 Technical Conference (8/10)

The principle of an aeroengine turbine is very similar to that of a car's turbine engine, which uses exhaust gas and fluid to impact the rotation of the impeller to generate power.

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

The most critical technology for aeroengine turbines is blade materials. Turbine blades are also one of the three major high-pressure components of aeroengines.

Turbine blades will provide huge power, but at the cost of withstanding high temperatures far exceeding the melting temperature of their metal and centrifugal tensile stress exceeding 10,000 Newtons. That is, in order for turbine blades to withstand high temperatures and high pressures, they must be as resistant to high temperatures as possible and possess high strength.

"We all know that if the design level of the engine turbine and fan is the same, for every 100K increase in the temperature in front of the turbine, the thrust will increase by about 15%!" Academician Liu said: "But we are limited by high temperature resistance and high pressure resistance. The place!"

"High temperature is the first hurdle for turbine blades. The temperature ranges from one to two thousand degrees or even higher. High-efficiency blades cannot be designed to be solid. Hundreds or thousands of cold air passage openings need to be added to each blade!" Liu The academician said seriously: "This will place very high requirements on material strength. For the engines currently developed, the material limitations are not only power, but also lifespan."

"The current level of the Beijing Aerospace Materials Research Institute in the industry has undoubtedly reached the first place..." Academician Liu introduced the latest achievements in turbine blade materials, as well as the ones being developed that may achieve breakthroughs in the next two or three years.

The Beijing Aeronautical Materials Research Institute was founded in 1956. It can be said that it has a long history and a very profound foundation. It has 22 research laboratories, including the Key Laboratory of Advanced Composite Materials Defense Science and Technology, 2 pilot processing plants, 13 pilot production lines and more than 20 associated factories. It is a large-scale research institute with complete expertise, advanced equipment and instruments, and intensive knowledge. hospital. It has nearly 3,000 employees, most of whom are scientific and technological personnel. The institute also has a graduate department with the authority to award doctoral and master's degrees.

The Beijing Aerospace Materials Research Institute has achieved more than 2,000 scientific research results so far, including more than 600 major results at ministerial level or above, and won more than 150 National Natural Science Awards, Invention Awards, and Science and Technology Progress Awards. It can be said to represent the highest level of China's composite materials. level.

Every year at science and technology conferences, the Invention Award and the Science and Technology Progress Award are always indispensable for the Beijing Aeronautical Materials Research Institute.

After Academician Liu finished speaking, Qin Yuanqing said: "From what you just introduced, the current D series high-temperature resistant materials such as DD2, DD3, DD4 of the Beijing Aerospace Materials Research Institute are all in the direction of single crystal nickel. Jing' is an advantageous method, but it's just a method."

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

The institute is currently unable to conduct verification at this level, but Qin Yuanqing, with Academician Liu's connections, can definitely handle it.

Although Academician Liu thinks this matter is quite nonsense, if a random formula can solve it, how can they who are dealing with materials be so worried that they are bald.

However, Qin Yuanqing is the dean, and now that the institute has money, it will be treated as a trial and error cost anyway.

Watching Academician Liu leave, Qin Yuanqing continued to focus on the engine fan: "This time the aero engine fan adopts a 3-stage fan design. The first-stage fan blade adopts a wide chord and hollow design, which is similar to the Pw4084 used on the Boeing 777. The hollow blade used in the engine has the same structure, that is, the blade is composed of two template plates, namely the blade basin and the blade back, which are connected into a complete blade by the diffusion connection method. Before connection, several channels are longitudinally milled out at the joint surface of the two plates to form a hollow blade. Cavity... The 3-stage fan rotor made of titanium alloy adopts an integral blisk structure, and uses linear friction welding to process the integral blisk!" Qin Yuanqing said to the fan design team.

Linear friction welding is a solid-state joining technology similar to diffusion joining. Diffusion connection is to tightly connect the connecting surfaces of two parts to be connected. Under high temperature and high pressure, a mutual transfer of material atoms is formed between the mating surfaces of the two parts, ultimately making the two parts tightly connected into one. In this connection, since the material at the connection is not melted, there will be no desoldering phenomenon that easily occurs in general welding. Structurally speaking, there is no "weld" visible at the connection, and its strength and elasticity are better than the main material. The difference between linear friction welding and diffusion joining is that in diffusion joining, the connected workpieces are heated in a furnace to reach high temperatures; while in linear friction welding, the high temperature of the workpieces is caused by mutual high-frequency interaction between the two mating surfaces. caused by oscillation.

The person in charge of the fan design room is Academician Bai. Academician Bai is 60 years old and has been engaged in aircraft engine fan design. The more he looks at the fan design drawn by Qin Yuanqing, the more he frowns.

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

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

Some things are like this. Older generations may find it difficult to accept new things, but it doesn’t matter. As long as you verify them carefully and understand them deeply, you can taste the benefits.

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

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

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

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

Although at the level of academician, you don’t need to offend anyone, but Academician Bai still admires Qin Yuanqing because of his courage. For example, as soon as the Aeroengine Research Institute was established, the salary of scientific researchers increased significantly. Even for academicians, the salary income is higher than that of Qin Yuanqing. It has improved a lot in the past.

Although it is said that academicians have no worries about life and are not short of money. But whoever has no children or relatives would not be happy if his salary could be raised.

Moreover, they have students of their own, and they couldn't do anything to exploit their students before. After all, they had no money, and scientific research funding was calculated on a per-cent basis. They wished they could use one dollar as two dollars.

Now that students' salaries are higher, their teachers are also happy.

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

However, this also puts a lot of pressure on many deans, forcing them to go to companies to solicit scientific research funding in order to improve the treatment of their subordinates. Otherwise, if the people's hearts are scattered, it will be difficult to lead the team.

Qin Yuanqing watched Academician Bai leave. It was estimated that with the strength of their laboratory, it would take at least three to five months to fully understand that information. As for creating a sample, it would definitely be next year.

Aviation engine technology, unlike other technologies, is a national treasure in any country. Even the United States hides this aspect from its allies. No one can even think of removing the F119 aero engine from a fighter plane. Do research.

It is because no other country has the F119 aero engine, so even though they know it is advanced, no country can copy it.

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

Next is the high-pressure compressor. The F119's high-pressure compressor adopts an advanced pressure ratio design, and the six-stage rotors all adopt an integral blisk structure. The front receiver is made of "Alloy c" flame-retardant titanium alloy to reduce weight. The static blades also use curved static blades. In order to increase the longitudinal rigidity of the casing at the outlet of the high-pressure compressor (where the diameter is the smallest and forms a waist), the combustion chamber casing is extended 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 serves as a containment ring for the airflow. This structure is widely used in large-scale, high-bypass-ratio turbofan engines.

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

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

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

As for the combustion chamber, it is among the most important, and can be said to be above the material. The combustion chamber is the inner part of the turbine engine that provides power. It can be said to be the heart of the turbine engine.

There are several types of aviation turbine engines, namely turboprop engines, turbojet engines and turbofan engines. The highest performance among them is the turbojet engine. When loaded on a fighter aircraft, it can easily provide supersonic power. The highest power can make the fighter aircraft fly The speed exceeds Mach 3, which is three times the speed of sound.

However, the fuel consumption of turbojet engines is very high, and the higher the power the engine provides, the better. There are also many issues such as practicality, fuel consumption, and endurance to consider.

A fighter jet can reach a speed of Mach 3, but each flight consumes a lot of fuel. Not only does it consume a lot of fuel, but high fuel consumption definitely corresponds to low endurance, and the maximum flight distance will be severely limited.

That's why turboprop engines and turbofan engines appear.

A turboprop engine can be understood as a turbojet engine with a propeller in front. 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 thrust of the turboprop engine 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 produce a lot of resistance during high-speed flight, so the turboprop engine is not suitable for high-speed flight.

A turbofan engine is between a turbojet engine and a turboprop engine. It can be understood as a fan installed in front of the turbojet engine. It can provide good power and can support a speed of 1,000 kilometers per hour. It also greatly reduces the engine's load. In terms of fuel consumption, the disadvantage is that the engine structural design and technology are too complex.