The aero engine is the heart of the aircraft, known as the "Pearl of the Crown" and "The Flower of Industry" of modern industry. Aviation engines are the power of aircrafts, and the demand and development of aircrafts have driven engines to a higher level.
Aero-engine is a knowledge-intensive, multi-disciplinary, high-tech and complex thermal machinery that needs to work repeatedly under the severe conditions of high temperature, high speed, and high load, and the technical performance, durability, reliability, and economic requirements are increasing day by day. Aero engine manufacturing involves many disciplines and technical fields such as aerodynamics, heat, control, materials, strength, and manufacturing, and is one of the most complex engineering technologies.
The development level of the aero-engine industry is a concentrated reflection of a country's industrial foundation, scientific and technological level, and comprehensive national strength. It is also an important strategic guarantee for national security and status of a great power.
While China's C919 is facing mass production, but China's commercial aero-engine CJ-1000A has not yet been developed and finalized, it is imperative for China's commercial aero-engine industry to achieve domestic production. According to COMAC's official website, the domestic C919 engine has completed all design work for the verification machine and is scheduled to enter service in 2025. However, CJ-1000A, China's first commercial aviation engine, has not yet been developed and finalized. China urgently needs to develop a domestic civil aviation engine.
Aero engines are so difficult to build? Where is the difficulty? The blade is one of them
The temperature in the main engine of modern aviation engines reaches 1800 ~ 1950K, the pressure reaches 50 atmospheres, and the rotation speed reaches 50000 / min, all of which pose severe challenges to the materials of engine blades and bearings. The mutual interference between aero engine components is large, and the mutual interference of the flow field and temperature field of the upstream and downstream components affects the engine's working stability and also increases the difficulty of engine development.
The blade is a key part of an aero engine. Its manufacturing volume accounts for about one-third of the entire machine manufacturing volume, and it is the largest number of parts in the engine. Aeroengine blades are thin-walled and easily deformable parts. How to control their deformation and process them efficiently and with high quality is one of the important topics in the blade manufacturing industry.
Aero engine blades are divided into fan blades, compressor blades and turbine blades according to their components.
Turbine blades are hot-end parts. They are made of high-temperature alloys and other materials, and are made through precision casting. It is very difficult.
For turbofan engines, the engine's thrust-to-weight ratio can increase by 10% for every 100 degrees Celsius increase in the inlet temperature of the turbine. The turbine blades are located behind the combustion chamber and complete the conversion from gas chemical energy to mechanical rotor energy. They are hot-end components and are directly related to turbofan engines. Performance. Turbine blades have high requirements for high temperature resistance. Under high temperature conditions, they must have sufficient toughness and fatigue resistance. Therefore, turbine blades are made of high-temperature alloys, and precision casting is commonly used for processing.
Compared with the titanium alloy materials or composite materials used in fan blades and compressor blades, the superalloy materials used in turbine blades are more difficult to smelt, and some of the metal resources (such as Yankuang) require less storage, and a large amount of resources are Controlled by European and American countries.
The fan / compressor blade market is dominated by European and American companies, but the forging technology of Chinese companies has made significant progress, and the forging blade industry is shifting to China.
The hollow blades and composite blades used for turbofan engine fan blades and low-pressure blades of compressors have high requirements on materials and manufacturing processes. The domestic start is relatively late. At present, the international market is still dominated by European and American companies. GE, Safran, Rolls-Royce, Pratt & Whitney and other international aviation engine giants all have direct-owned factories or set up joint venture factories with cooperative companies, such as the Albany / Safran joint venture factory and CFAN.
With the continuous improvement of China's forging technology, domestic forged blades have global competitiveness. From a cost perspective, the international aviation engine giant has increased its purchase of forged blades in China. HFDL, HYKJ, WXTP and other companies have successively won large orders for forged blades, and the forged blade industry is shifting to China.
Precision-cast blades (turbine blades) have long been monopolized by Europe and the United States, and domestic enterprises have made significant progress, and their main performance needs to be improved.
Turbine blade production is difficult and has been monopolized by European and American companies for a long time. In addition to the cold-end components, in the air duct of a high-performance jet engine, the turbine inlet temperature exceeds 1600 ° C. At the same time, the blades need to withstand high-temperature gas flushing of the engine starting and stopping cycles, temperature change, and centrifugal force at high speeds. This requires Alloy materials have certain creep strength, thermomechanical fatigue strength, and corrosion resistance to sulfur media at high temperatures. High-performance, long-life turbine precision-casting blades are provided by European and American companies. GE, Safran, Rolls-Royce, Pratt & Whitney and other international aviation engine giants have direct-owned turbine blade factories. PCC is the largest independent turbine blade supplier.
Domestic enterprises have made significant progress, and a number of companies such as Aviation Development Precision Casting and Yingliu Co., Ltd. have made breakthroughs in turbine blades, and have greater room for development. After years of development, domestic turbine blade technology has made significant progress. Among them, HF precision casting has achieved stable supply of turbine blades, and blade performance and life have been continuously improved. It is the most important turbine blade supplier in China; YLGF, JSYH, WZGF achieved technological breakthroughs and succeeded. Enter the supplier sequence of China Aviation Development.