Research progress of the hottest aero intelligent

The technological development level of aero-engine is an important symbol of a country's science and technology, military strength and comprehensive national strength. The United States leads the world in aero-engine technology. The integrated high performance turbine engine technology (IHPTET) program implemented since 1988 is the engine technology pre research program with the widest scope, the highest degree of innovation, the largest scale, the strongest influence and the most investment in the world so far. Although the objectives of the third phase of the IHPTET program have not been reached, and the development work is still continuing, the U.S. Department of defense, NASA and the defense advanced research agency have formulated a long-term development plan for propulsion technology that will continue to 2017, that is, the vaate program, the successor program to the IHPTET program that began to be implemented in 2006, that is, the universal and affordable advanced turbine engine program

vaate program aims to improve engine performance while emphasizing reducing production and maintenance costs. Its main purpose is to develop and verify affordable multi-purpose core machine technology, and then develop civil and military engines with higher performance, higher durability and lower cost from the core machine. The development focus of vaate plan is economic affordability. The overall goal is to develop revolutionary and innovative technologies by 2017, so that the economic affordability of advanced military engines can be increased to 10 times that of F119 engines, the thrust weight ratio can be increased by 20% ～ 30%, the fuel consumption can be reduced by 25% ～ 30%, and the development, production and maintenance costs can be reduced by 50%

vaate plan has key area group, common technology group and technology application group. In the key area group, there are three groups: general core machine, intelligent engine and durability. The intelligent engine team is responsible for the development, verification and transformation of advanced aerodynamics, advanced materials and innovative structures, combined with the provision of sensors, active controllers, aircraft engine integration, import and nozzle integration, real-time diagnosis and artificial intelligence technologies, to develop and integrate those technologies that provide long-lasting, adaptable and damage resistant engine status and life management features, Realize the health management of the engine, and improve the performance, reliability and service life of the engine. This is the core content of the vaate plan

in the 10-year plan for civil aviation technology formulated by NASA in 2006, the "intelligent engine and mechanical power system capable of self diagnosis and reconfiguration during maintenance interval" and "affordable new sensors" are specifically identified as challenging research and Technology (r&t) development projects in the field of civil aviation in the United States in the next 10 years

richardfisher, a think tank expert of the US international strategy and evaluation center, pointed out in an article: facing the pressure of competition between China and Russia, the US military must purchase a sufficient number of generation 5 aircraft, or even develop generation 6 aircraft, in order to maintain air superiority. In the future, the 6th generation aircraft will mainly focus on artificial intelligence, especially the application of intelligent engine technology. In the science fiction film top secret flight, Eddie is a fighter controlled by artificial intelligence

aero intelligent engine is developed under this background

concept and characteristics of intelligent engine

the current engine is set and inflexible, and can not respond to the changing environment. These problems must be paid full attention to. As a result, a great margin is left in the design, use and maintenance concept, so that its performance is adversely affected and the support cost is increased. Therefore, the future military and civil engines will develop into intelligent engines. The so-called intelligence means not only feeling, but also thinking. It can be operated according to predetermined procedures or thinking. This process is described in one word as "learning". By improving the "learning" ability, a super intelligent engine is developed

intelligent engine is an advanced new concept aeroengine technology, and the key part is the engine intelligent management system. The system has the ability to control engine performance and diagnose engine "health" conditions, which are closely related. The intelligent engine can prolong the service life of the engine through the adaptive control of the engine and various components. At the same time, intelligent engine can fully understand the environment and engine status by relying on sensor data, expert model and their fusion; Information fusion technology is widely adopted (each engine is a station). The engine status monitoring and management (EHM) can realize automation, self diagnosis and self prediction, actively self manage the engine performance and status, provide the best information to make decisions according to the requirements of environmental balance tasks, and take physical actions to implement these decisions; The intelligent engine generally does not need maintenance, unless the self inspection or detection system sends a maintenance signal and accurately points out the maintenance measures to be taken

key technologies of intelligent engine

1 intelligent engine control technology

(1) tasks and contents of intelligent engine control. The engine is the "heart" of the aircraft and the source of promoting the rapid development of the aircraft. Xiao5tai primary school in Yingze District, Taiyuan city held a lantern show and the activity power of celebrating the Lantern Festival in the new year with the theme of "turning waste into treasure, ingeniously making lanterns and smart campus show". To make the "heart" of the aircraft work healthily, it depends on the excellent control of the "arteries, meridians and nerves" system. Modern aero-engine control system has become a complex system with multi variables, time-varying, nonlinear and multi-function. More and more parameters are required to be controlled (up to 6 ~ 10 at present, and will increase to 20 in the future). The new generation variable cycle engine, intelligent engine and flight/propulsion system integrated control all require more control variables, and the controller must have stronger computing power, logic function and control accuracy. It is obviously too complicated for traditional mechanical hydraulic controller to realize these requirements. Digital electronic control has significant advantages in weight, cost and reliability. Therefore, developed countries pay special attention to the development of engine digital electronic control technology, and do not hesitate to spend a huge amount of money (accounting for 15% ~ 30% of the engine development cost) to research, so as to meet the best tactical and technical or economic performance requirements of aircraft

the development goal of aeroengine control system technology is to become an optical fiber control system that can improve data processing capacity and prevent electromagnetic interference. It integrates the functions of performance optimization, flight and engine integrated control, advanced sensors and actuators

engine intelligent control tasks include: steady state control, over state control and limit control. The content of aeroengine control includes: fuel flow control of main combustion chamber and afterburner; Angle control of fan and compressor guide vanes and rectifier blades; Control of nozzle area and nozzle area ratio; Compressor interstage bleed valve control; Active control of compressor and turbine tip clearance; Vectoring thrust nozzle control; Internal and external culvert to culvert control; Reverse thrust control; Engine cooling control; Stall/surge protection control; Acceleration/deceleration control; Overtemperature, overspeed and overpressure protection control; Flame detector control, etc

the main component of the aeroengine digital electronic control system is the digital electronic controller, which is composed of signal processing and conversion circuit, digital electronic computer with microprocessor as the core, output signal conversion and amplification circuit, power supply and other modules. The microprocessor completes the functions of signal acquisition, control operation and control signal output through running program; The engine can be controlled, monitored and protected through various actuators. In order to ensure the reliable operation of the controller, the problems of cooling, anti vibration and anti electromagnetic interference must be solved. At present, electronic controllers generally adopt redundancy design to make the reliability index of electronic controllers reach a higher level

(2) key technologies of aeroengine intelligent control. The related technologies and main technical difficulties of aeroengine intelligent control include:

· accurate airborne engine real-time model modeling technology

· high performance electronic controller design technology

· secondary integration and special chip design technology

· controller anti harsh environment technology (cooling, electromagnetic compatibility)

· advanced application software design technology (realizing software dissimilarity redundancy)

· advanced control mode design (multivariable control algorithm, various adaptive control algorithms)

· sensor redundancy design and advanced analytical redundancy technology

· design of fuel pump and metering device with high speed, large flow, high pressure and light weight

· status monitoring, software and hardware fault diagnosis and processing technology

(3) Aeroengine Digital electronic control technology. The United States is currently implementing a future advanced control technology research (FACTS) program, which aims to further realize the miniaturization, integration, high performance and high reliability of the power control system. Specifically:

· miniaturization: by adopting advanced lightweight materials and advanced system (distributed, optical fiber, electric driven pump) structure, the weight and volume of the control system are greatly reduced, and the ultimate goal is to reduce the weight of the system by 50%

· integration: ultra high speed integrated circuit and parallel technology are adopted to improve the processing capacity of the system, realize the integration of power control and status monitoring, and then realize the integrated flight/propulsion control

· high performance: by studying the control modes and logic of advanced inlet, engine and vectoring nozzle, advanced control theory and integrated control are adopted to improve the performance of power plant. The goal is to reduce fuel consumption by 5% and increase thrust by 10%

· high reliability: adopt distributed system to reduce the complexity of control system and improve maintainability and reliability; Install the controller away from the engine; Gallium arsenide and silicon carbide devices are used to manufacture electronic controllers, and composite materials are used to manufacture oil pumps and metering components to improve the high temperature resistance, vibration resistance and electromagnetic interference resistance of the system. The goal is to make the temperature resistance up to 220 ℃

the most advanced 3rd generation full power digital electronic control system (FADEC) adopted by F119 engine developed in the United States is developed under a comprehensive, reliable and fault-tolerant control plan. The system has 12 ~ 13 controllable parameters, has double double redundancy and fault-tolerant capability, and can perform module reconfiguration. Due to the improved reliability, there is no hydraulic mechanical backup. The system can perform fault diagnosis and treatment for the engine and vectoring nozzle, has comprehensive diagnosis of condition based maintenance (OCM) and logistics support, and can determine the best working parameters of the engine according to the integration of the aircraft propulsion system

as early as the 1980s, NASA organized Ge and p&w to identify the most valuable advanced control concepts through detailed evaluation: intelligent control concept (IEC), performance optimization control (PSC), stability optimization control (SSC), active stall/surge control (ASC), active tip spacing control (ATC), active compressor distortion control (SSC), active noise suppression (ANS), secondary cooling air flow control (SCAC) Active combustion chamber outlet radial temperature distribution factor control (BPF), active fuel nozzle classification (AFN), afterburner fuel air ratio optimization (f/aopt), etc. The most important advanced control concepts are IEC, PSC, SSC and ASC. The research results show that IEC is greatly superior to other control methods. According to the calculation method of Ge, its income is higher than the second psc50%. The development direction of electronic digital control technology is integrated control, distributed control and multi