The self-developed new material from Dalian University of Technology increases the service life of China made bearings by 6 times

The fuel pump is known as the "heart" of the aircraft engine

The oil pipeline is like the "heart artery"

The high-speed thrust bearing plays the role of a "stent" for blood vessels

On March 22, Guangming Daily reported that our school's student team

made domestic bearings through independent research and development of new materials

Increased the service life of domestic bearings

from less than 1,000 hours to 6,000 hours

Achieved a comprehensive benchmark with the world's top technology

Let's take a look at their stories

The fuel pump is known as the "heart" of the aircraft engine. Its main function is to pressurize the fuel through the meshing and rotation of gears, suck the fuel from the fuel tank into the oil pipeline, and then transport it to the combustion chamber. The oil pipeline is like the "heart artery" of the aircraft engine. The gears rotate at high speed inside it and need to be stably loaded. The high-speed thrust bearing plays such a "support" role.

The service life of high-speed thrust bearings of foreign aircraft engine fuel pumps exceeds 6,000 hours, while the service life of bearings currently in service in my country is less than 1,000 hours, which is difficult to adapt to the development needs of lightweight and long-range modern aircraft, and has become a bottleneck problem restricting the performance leap of my country's aircraft engines.

In the national finals of the China International College Student Innovation Competition (2024), Bao Qingguang from the School of Chemical Engineering of Dalian University of Technology demonstrated the domestic bearings developed by the team over a period of three years, with a service life of 6,000 hours, providing a feasible solution for the effective replacement of new materials for key equipment of major countries.

Let young people take on big tasks. Soon after Bao Qingguang entered the University of Technology, he had an exchange with his mentor, Academician Jian Xigao, on research directions. Academician Jian said to the freshman straight to the point: "The research group has a project on aircraft engine bearings, which is an important task to solve the urgent needs of the country. Are you interested in participating?"

Bao Qingguang did not expect that a freshman graduate student would have the opportunity to participate in such an important research project, but seeing Academician Jian's serious attitude, he answered with a fearless attitude: "I am very willing."

The "13th Five-Year Plan for National Science and Technology Innovation" selected a number of major scientific and technological projects that reflect the national strategic intentions for key research and development. The "Aeroengine and Gas Turbine" project ranked first. One of the key technologies is the development of a new type of aircraft engine fuel pump high-speed thrust bearing that Bao Qingguang is "very willing" to participate in.

The material of the current bearings is mainly copper alloy, which is heavy and does not have self-lubricating function. It is necessary to spray anti-friction coating on the surface. After the coating is worn out, the life of the bearing will soon expire. At the same time, the service environment of bearings is very complex and harsh, especially in the case of extreme combat of fighter jets, the speed is greater than 8000r/min, the load exceeds 12MPa, and the temperature is as high as 150℃.

After analysis, the team members believe that to develop new bearings, it is necessary to develop new materials to replace copper alloys. This new material must have high temperature resistance, high strength, high wear resistance, and self-lubricating functions.

"The resin-based composite material developed by our team has advantages in high temperature resistance. If we follow the twisted non-coplanar molecular structure design idea innovatively proposed by Academician Jian, and carry out targeted transformation and optimization of existing technologies and materials, it is feasible to apply it to bearings." After Bao Qingguang had a direction in mind, he reported his work ideas to the research team.

"Young people, I believe you can do it well." Academician Jian recognized and encouraged the work of the young team.

Smell the "good formula" under the fireworks. The new material needs to solve the problem of balancing friction performance and mechanical properties, which are mutually restricted. The characteristics of the material are determined by the types and ratios of different fillers. The team needs to find the best balance between friction performance and mechanical properties by constantly changing the types and ratios of fillers, so as to find the "good formula" that is most suitable for bearing materials.

Bao Qingguang said: "The most difficult thing is that we don't know the specific data of this "best fit", and we must find the "best fit" from the "suitable". According to the previous research foundation of the research team, to improve the performance of the material, 5 nano-scale fillers are needed, and the mass fraction used must be accurate to 0.01%, and the proportion of each filler may be between 0.01% and 30%. "This means that the number of experiments cannot be estimated, and it is impossible to guarantee that the task will be completed within the time limit." Team member Wang Bing said: "It's like seeing the top of the mountain when climbing a mountain, but you must find a closer way to arrive on time."

The team began to constantly think about how to find a shortcut. It happened to be the Chinese New Year, and Bao Qingguang saw fireworks blooming in the night sky. The thick smoke suddenly reminded him that when making gunpowder, the power of gunpowder can only be exerted when the proportion of carbon, sulfur and saltpeter is appropriate, which is similar to the "formula" for developing materials. The sudden inspiration made him excited, and he quickly searched for literature on the design of gunpowder formulas. After a holiday search, he found the mixed material experimental design method.

Through this design method, the mapping relationship between material composition and friction performance can be constructed, and the synergy between the components can be quantitatively analyzed from a mathematical perspective, so as to find the "suitable" specific data range more quickly. Then through test verification and comparison, find the "most suitable".

With a clear idea, the team devoted themselves to experiments day and night. In 10 months, more than 300 groups of experiments were used to prepare more than 3,000 splines. After more than 1,000 tests, short-cut carbon fiber reinforced polyphenylene ether self-lubricating functional composite materials were made. At the same time, the team established an interface strengthening method for heterogeneous and heterogeneous complex interface systems for the first time, which improved the wear resistance of the material by 74%.

Team member Wang Ning proudly introduced: "We conducted six domestic and international tests on the material's performance and concluded that the material's glass transition temperature is above 280°C, its bending strength is greater than 200 MPa, and its friction coefficient is less than 0.1. Compared with similar materials currently leading in the world, its performance is superior."

New challenges are coming one after another in the continuous innovation. When the team tried to make the composite material into a bearing product, the user unit reported that the bearing components had a serious problem of poor dimensional stability. This means that the previous experimental results may not be transformed and implemented.

The team invited Mr. Li Nan, a composite material technology expert in the research group, to take the pulse and ask questions. Under his guidance, the team repeatedly tried and adjusted the molding process dozens of times, and decided to abandon the traditional one-time molding technology of molding, and innovatively proposed the product manufacturing idea of "combining extrusion-molding-machining". More than 300 bearing components were prepared in more than 6 months.

The mass of these bearing components is only 1/6 of that of traditional bearings, and no longer needs to be coated with lubricants. They have successfully passed the strict assessment of 12,000 rpm and 6,000 consecutive hours required by the user unit, exceeding the requirements of international first-class standards.

The team members have always used innovation to solve the problems encountered in the research and development process: in three years, they have mastered three key core technologies, including low-cost and high-performance controllable preparation technology of resin matrix, integrated design and preparation technology of composite material structure and function, and interface chemical structure regulation technology of composite materials, applied for five national invention patents, and published 15 high-level papers.

The wear-resistant self-lubricating resin-based composite materials developed by the team have been verified in the thrust bearings of aircraft engine fuel pumps and the thrust bearing pads of large ships. They can also be promoted and applied to wear-resistant parts in high-tech fields such as aerospace, vehicles and ships, and petrochemicals, and have broad application prospects. At the same time, the key technologies mastered are ahead of the international level, which has won more international voice for the domestic aviation and ship materials industry, and is of great significance to promoting the upgrading of technology products in my country's aviation engine and ship power industry and improving the development level of strategic emerging industries.