At the beginning of the new year in 2022, China's leading ultra-high temperature ceramic matrix composite material manufacturer: XBGY Advanced Ceramic Technology Corporation developed a ceramic matrix composite monolithic turbine disk successfully completed its first aerial verification. This test shows that a breakthrough has been made in the application of Chinese ceramic matrix composites in aero-engines, which lays a solid foundation for the manufacture of high-temperature compressors for aero-engines with ceramic matrix composites in the future.
Ceramic matrix composites are one of the most promising materials for future aero-engines, and are the key materials to improve the performance of aero-engines. It is generally believed that when the engine thrust ratio reaches or exceeds 15, it is necessary to use advanced materials such as ceramic matrix composites to ensure that the engine performance meets the standard.
Aircraft engines are heat engines. Its thrust comes from the energy generated by the thermal expansion of the air. Therefore, a key indicator that determines the thrust of the engine is the temperature difference between the intake and exhaust ports. The greater the difference between the two, the higher the degree of air expansion, and the greater the energy generated. Since the air temperature is constant under certain conditions, the increase in engine thrust is largely determined by the exhaust port temperature. However, the exhaust port temperature also has constraints, that is, the high temperature turbine withstand capability. When the hot gas rushes out of the combustion chamber, the first component it encounters is the high-temperature turbine. The high-temperature turbine uses the gas to obtain energy and drives the high-pressure compressor to work. Therefore, the temperature that the high-temperature turbine can withstand directly determines the performance of an aero-engine. Modern aero-engines Much of the performance improvement revolves around increasing (high temperature) pre-turbine temperatures.
Aero-engine technicians believe that the temperature before the engine turbine is increased by 100 degrees, and the engine thrust can be increased by about 20%, which can be said to have a significant effect. The temperature before the turbine of the fourth-generation aero-engine has reached 1800 degrees, which is close to the limit of metal materials, and it is very difficult to develop further. According to industry forecasts, the temperature before the turbine of the high thrust-to-weight ratio engine used in the sixth-generation fighter jets will exceed 2,000 degrees, which puts forward higher requirements for high-temperature turbines. Manufacturing high-temperature turbines with stronger temperature resistance, lighter weight and longer service life has become the bottleneck of the sixth fighter engine, and ceramic matrix composites are the key materials for manufacturing such high-temperature turbines.
The use of high-temperature turbines made of ceramic matrix composites can increase the temperature before the turbine and increase the thrust of the engine. Due to the lower temperature of the fuel chamber, the fuel burns more fully and releases more energy, which is also conducive to reducing fuel consumption. It is also very important that the ceramic material is light in weight, and the engine parts made of it are also lighter, which can reduce the weight of the engine and get a higher thrust-to-weight ratio. For the aircraft, the weight of the engine is reduced, and the weight of the aircraft structure is also reduced, which further improves the overall thrust-to-weight ratio of the aircraft.
The test flight is a ceramic matrix composite turbine disk, which forms a high-temperature turbine with the turbine blades, and the high-temperature turbine is one of the key components of the aero-engine core machine. The core engine of modern aero-engine mainly includes high-pressure compressor, combustion chamber and high-temperature turbine, which are the key components of the engine. It is generally believed that after the completion of the core technology of aero-engine, the development of one aero-engine is equal to 80% completed. Therefore, it is speculated that the domestic sixth-generation fighter engine, that is, the high thrust-to-weight ratio engine, has entered the development stage of key components. The technological achievements of 6th generation fighter engines can also be used to improve and enhance existing aircraft engines, enhancing their performance.
CFM's Leap-1A civil turbofan engine equipped with ceramic matrix composite (CMC) high-pressure turbine shroud rings successfully completed its maiden flight on the new Airbus A320neo aircraft on May 19, 2015, indicating that CMC has a strong role in aeroengines. New breakthroughs have been made in the application of hot-end components. The application of CMC to the hot-end components of the engine has also received great research attention.
The engine adopts the CMC high-pressure turbine shroud ring (a static annular seal that surrounds the high-pressure turbine rotor blades and prevents the leakage of hot exhaust gas from the turbine blade tip). hundred kilograms. The CMC high-pressure turbine cover ring has completed more than 20,000 hours of component and complete machine tests. The tests show that it can greatly reduce the demand for cold air drawn from the compressor, improve engine thrust, and reduce fuel consumption by more than 1.5%.
Turbofan engine, equipped with advanced ceramic matrix composite material tail nozzle adjustment plate; turbofan engine adopts high temperature resin matrix material extension casing and some static structures using ceramic matrix composite material or carbon-carbon material; turbofan The engine nozzle adjustment sheet is made of silicon carbide-based ceramic material; the secondary sealing sheet of the tail nozzle of the turbine engine is made of ceramic matrix composite material (CMC).
Some advanced ceramic matrix composites research institutions in China
Research Group of Ceramic Matrix Composites, SHGS Institute, Chinese Academy of Sciences:
The research group was established in 2005. Since then, it has carried out in-depth and systematic research in the field of advanced carbide ceramic matrix composites. Starting from the structural design of prefabricated body, optimization of interface structure and function, matrix modification and performance regulation, etc., a series of carbide ceramic matrix composites with excellent characteristics and key preparation technologies have been developed, and the realization of carbide ceramic matrix composites can be achieved. Control devices and applications.
SD Ceramic Matrix Composite Engineering Technology Research Center:
The research center takes advantage of the technical support unit of the national new material achievement transformation and industrialization base to actively attract domestic and foreign achievements in new materials (especially composite materials and high-tech ceramics), and utilize the center's advantages for transformation and development. Realize industrialization as soon as possible, so that ceramic matrix composite materials and high-tech ceramics can gain advantages in market competition; at the same time, moderate research and development of metal matrix composite materials, carbon/carbon matrix composite materials, polymer matrix composite materials, and functional composite materials will drive regional economic growth. developing.
XBGY: The R&D center is based on the technology that has won the first prize of the National Technology Invention Award, and is based on the National Defense Key Laboratory. It is a new attempt and new platform for engineering application and industrialization development.
As the core support team of the key laboratory of ultra-high temperature structural composite materials, the ceramic matrix composite material team has been engaged in the manufacture and application technology research of ceramic matrix composite materials for 20 years since its establishment. It is the pioneer of this technology field in China and the engineering application of this material the leader. The team was among the first to be awarded the title of Outstanding Scientific and Technological Innovation Team in the National Defense Science and Technology Industry. The ultra-high temperature structural composite material team with the ceramic matrix composite material team as the main body was selected as one of the first batch of innovation teams of the Ministry of Education, and was continuously supported by the National Natural Science Foundation of China's innovative research group project twice, and won the National Defense Science and Technology Innovation Team Award.