Domestic aero engines have made significant progress, but they still lag behind advanced countries
Some time ago, the Aviation Industry Corporation of China (CNAC) received good news that the new AES100 civil turbojet engine successfully completed airworthiness tests under freezing conditions, achieving a technological breakthrough in this field.
The AES100 is a typical civilian *** and its ice tests are conducted in adverse weather conditions to verify its safety and reliability.
According to the plan, AES100 is expected to obtain the China Civil Aviation Airworthiness Certificate in 2024, which will be able to meet the energy needs of various aircraft such as civil drones.
We were happy, but we needed a basin of cold water. While we have come a long way in the field of aircraft engines, we still have a long way to go compared to the United States 30 years ago.
When we talk about domestic aircraft, we think of domestic engines, and when it comes to engines, we all think that our technology is too far behind the United States, at most only thirty years old.
The topic of some time ago was domestic motors, at what level can we finally fight?
How aircraft engines work.
In addition, the engine is considered the jewel in the crown of industry, along with lithography and more than a dozen basic technologies that the country has not yet fully mastered.
Introduced in 1937, this engine is almost a century old, but its operating principle has remained the same.
The heart of an internal combustion engine is made up of three parts: the compressor, the combustion chamber, and the turbine.
During operation, the engine rotates the intake vanes, sucks in and compresses the outside air, which is then fed into the combustion chamber, where it is mixed with the injected fuel for combustion, creating thrust.
If it were just that, it would be called a turbojet engine because it consumes a lot of fuel and is inefficient.
How can this be done? A turbine and propeller shaft are added to the back of the engine, and the turbine rotates to drive the fan, low-pressure impeller and high-pressure impeller to compress the air in the engine and then mix it with fuel to produce powerful thrust.
This is a turbofan engine.
The most important feature of a turbofan engine is the dual nozzle assembly, through which the airflow drawn by the engine passes through the inner ring (inner nozzle assembly) and the outer ring (outer nozzle assembly).
In this case, there is a term called"Flow ratio", which refers to the ratio of the airflow in the outer diffuser to the airflow in the inner diffuser.
Due to the different length-to-width ratios of the channels, they can be divided into small channel ratio internal combustion engines and large channel ratio internal combustion engines. The most intuitive difference between a small channel ratio engine and a large channel ratio turbofan engine is that one is thicker than the other.
A small jet accelerates much better than the engine and maneuvers much better, especially on a fighter jet, but it consumes too much fuel. It doesn't work in the air either. Due to the lower height, the aerodynamic efficiency of the fan is greatly reduced.
If the flow ratio of the engine is large and the fan diameter is large, the gas can provide more power, thus improving the efficiency of the engine; The more thrust, the more fuel is saved.
Of course, you can also use propellers, such as ***'s propellers. It's like a propeller on a ship.
Conclusion: As long as you can control the core, you can turn it into more useful functions.
The mystery of aircraft engines.
At present, only the United States, Russia, the United Kingdom and France have the ability to develop high-performance aircraft engines on their own, which is a major challenge. Details.
1.High requirements for safety and reliability; Civil aircraft engines have a service life of 30,000 hours and should reach 100,000 hours in the future;
To ensure flight safety, a drop test and an ice absorption test were also conducted.
Throw a few birds into the engine, but make sure the engine is running smoothly. Fill the engine with a ton of ice in one minute without damaging it.
2. High rotation speed and strong centrifugal force;
When the engine is running at 15,000-16,000 revolutions per minute, the centrifugal force on each engine blade is 10,000 times its own weight, or 15 tons, which is equivalent to lifting several cars.
3.Strict requirements for materials;
The temperature of a military aircraft engine is 1700 degrees, and the temperature of a civil aircraft engine is 1500 degrees, and the metal has melted, but it continues to work.
One can imagine how difficult it is to obtain the necessary materials.
When the wind reaches force 4 or 17, the flame is stable and does not flicker.
When the aircraft takes off, the engine is pumped and the wind force reaches level 17, at this time the flame must be kept burning evenly, not extinguished, and not changed direction, otherwise the engine will **. This requires good aerodynamic performance of the aircraft.
What kind of domestic engine are we talking about?
World No. 1 Cohan Dobby.
We compared the domestic WS-15 with the American F-119.
The thrust of the F-135 engine is greater than that of the WS-15 engine. So, are the engines of the American F-135 really more advanced?
We compared the native WS-15 fighters with the American F-119 fighters, which have a wingspan of 025 meters and 102 meters.
The F-119 has a gear ratio of 03. The diameter is 113 meters, but the maximum thrust is only 159 tons. Although modified to improve the gear ratio, 15The thrust of 9 tons is still slightly lower than that of the WS-15.
The American F-135 has a thrust of 057。Maximum thrust is obtained by deceleration.
When the speed drops to 1At Mach 6, it has a maximum thrust of 195 tons.
Our J-20 is armed with 2The WS-8 at Mach 15, which is very fast, much faster than the American F-35.
It is known that with each acceleration, the air resistance increases fourfold, and the surface temperature of the aircraft increases tenfold. This is an enhancement of the machine's material.
According to the specifications, the WS-15 has a smaller engine diameter and smaller passages, but its air intakes are higher than the F-119, which means that the blades of the WS-15 have a higher rotational speed.
The higher the speed, the greater the need for materials, which means we have a breakthrough in engine materials, but this has not yet been officially announced.
Suffice it to say, we achieved a lot with the small Düker engine, and more than one aspect.
What's more, in civil aviation, there aren't enough engines to take advantage of large air ducts.
The engine used in the Chinese C919 is not domestic, but the CFMLEAP-1C, a mid-mounted twin-jet turbojet engine jointly developed by General Electric of the United States and Safran of France.
The CK 1000 and CK 2000 are two aircraft currently under development in China, mainly for the C919 and C929 aircraft.
The CJ1000 is not yet in commercial use, but it is still slightly lower than the LEAP-1C.
Thrust Delay: The CJ1000 engine has an input ratio of 106:1, large thrust between 11 tons and 13between 5 tons; The LEAP-1C has a flight ratio of 11:1 and a thrust of 124 tons and 13between 5 tons;
Size, pressure ratio: CJ1000 fan diameter 195 meters, length 329 meters with a 22-phase compressor with a total pressure ratio of 47:1;LEAP-1C length 45 meters, fan diameter 198 meters with a 23-phase compressor with a total pressure ratio of 50:1.
Materials: CJ1000 is made of TC4 type titanium alloy, while LEAP-1C is made from 3D fabric molds.
leap-x"The engine was introduced on July 13, 2008, 15 years ago, which means that our in-house developed engines are nowhere near as good as our competitors 15 years ago.
It was not until 1990 that the F119 engine officially entered the flight test stage, and it was not until 1991, more than thirty years ago, that it began mass production. Compared to the competitors of 30 years ago, our WS-15 is only slightly superior.
Therefore, many netizens believe that China's engine is thirty years worse than that of the United States.
But I would say that we are 30 years behind in technology and more than 100 years behind in engine development.
However, we are also aware that after the collapse of the Soviet Union in 1991 and the rise of the United States as the world's sole superpower, the United States has regressed in many areas, especially when it comes to aircraft engines.
European and American aircraft engines have not been overhauled for more than 30 years, and the 30-year-old F119 is still one of the best three engines.
If we maintain the current pace of development, we will soon catch up with or even surpass European and American countries.
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