On December 23, 2019, JSXY New Materials Technology Co., Ltd. won the first prize of scientific and technological progress for the "Key Technology R & D and Industrialization of High-Performance Carbon Fiber Composite Materials and Structural Parts for Aerospace".
The carbon fiber composite fan blades developed by the company have entered the trial production stage, marking that China has mastered this key technology, laying a solid foundation for the performance upgrade of the domestic large bypass turbofan engine.
Domestic carbon fiber composite material fan blades will be used in CJ series large bypass engines, including CJ1000A engine, the latter is a matching engine for C919 passenger aircraft. After CJ1000A is replaced with carbon fiber composite material fan blades, the performance is better and the fuel consumption rate is lower. Taking the performance of the C919 airliner one step further, it has effectively enhanced the competitiveness of the airliner in the domestic and foreign markets.
For large bypass ratio turbofan engines, fan blades are one of the key components. Its role is to suck in air and provide continuous energy for the combustion chamber, so the performance of the fan blades determines the engine performance to a large extent. From the principle of turbofan engine, we can know that the greater the bypass ratio of the engine, the lower the fuel consumption, so the bypass ratio of modern civil passenger aircraft engines shows an increasing trend.
However, there is a problem that the larger the bypass ratio of the engine, the larger the diameter of the fan will increase, and the weight will increase accordingly. According to relevant information, the mass of the fan has accounted for about one-third of the total weight of the engine. After the weight of the fan increases, the weight of the drive box and the transmission system will increase, and the weight of the aircraft body and structure will also increase. As a result, the weight of the aircraft structure will increase, reducing the economy of the aircraft.
This creates a contradiction. Larger fan blades must be used to increase the bypass ratio, but larger fan blades mean greater weight and affect the economy of the aircraft. In order to solve this problem, composite material blades have appeared.
The blades of the engine are made of carbon fiber. Since carbon fiber is much lighter than metal, the weight of composite blades is much lighter than metal blades. For example, it is about half lighter than the existing titanium alloy blades, and the effect can be said to be very significant.
The LEAP engine currently used in the Chinese C919 aircraft uses carbon fiber composite blades. The weight of the engine is nearly 500 kg less than the engine using titanium alloy blades. In addition, the weight of the airframe is reduced, and the weight of the aircraft structure is reduced by about 1000 kg. This is for passenger aircraft. Produce very large economic benefits.
On the other hand, composite materials are also better processed than metals, and it is easier to make complex curved surfaces, so that the blades will be more close to the airflow when working, improving work efficiency. In contrast, it is very difficult to process metal blades into complex curved surfaces, thereby reducing the efficiency of the engine. However, when the fan blades rotate at high speed, they also have to withstand the impact of external forces. The blades require high strength and rigidity, which is very difficult.
At that time, Rolls-Royce's development of composite blades failed to achieve a breakthrough, and was once on the verge of bankruptcy. The British government had to localize it. Rollo is one of the three giants of modern civil aviation engines. It is so difficult to develop composite material blades. The difficulty can be imagined.
When China's relevant units developed the first generation of domestically produced large bypass ratio turbofan engines, considering the domestic carbon fiber level and the difficulty of developing composite blades, they did not use composite blades, but still used titanium alloy blades.
With the improvement of China's carbon fiber technology, many Chinese carbon fiber companies have been able to mass-produce T800 and T1000 grade carbon fiber, thus laying a solid foundation for the development of domestic composite blades. JSXY has established a professional team through the introduction of technology, breaking through a series of technical difficulties and obtaining a large amount of data, paving the way for the engineering of domestic composite material blades.
After the successful development of the domestic composite blades, it will replace the existing titanium alloy blades and improve the performance of the domestic large bypass turbofan engine, thereby further promoting the performance upgrade of domestic passenger aircraft and transport aircraft.