学科发展研究(2012-2013)分述
航空科学技术
2014年04月01日

一、引言

  随着创新型国家建设进程的不断深入,航空科技的战略性地位更加突出。2012至2013年期间,我国航空科学技术蓬勃发展,一大批航空新产品的研制也取得重要进展。航空科学技术是工程性很强的学科,其进展与工程技术成就紧密相连,其成果应用特别是集成性应用往往通过工程技术成就体现。本报告力求从学科进展的视角对航空科学技术的发展进行分析研究,通过对我国航空科学技术的新进展、新成果、新见解、新方法、新技术及时总结并与国际先进水平进行比较研究,分析航空科学技术学科发展动态、总趋势及前沿热点;对照国家经济社会发展战略需求,分析我国航空科学技术发展前景,提出重点研究方向的建议。

二、本学科近年来最新研究进展

  (一)飞机和直升机技术方面

  2012至2013年间,我国在飞机和直升机技术方面取得了重大突破。军用飞机方面,歼-20已经开始在阎良试飞中心进行定型试飞;歼-31于2012年10月31日完成首次飞行测试,标志中国成为除美国外第二个同时开展两种五代机研制的国家;由中国西安飞机工业集团研发的运XX重型军用运输机是有史以来中国研制的最大型军用飞机;首架歼-15原型机在辽宁号航空母舰上成功进行着舰测试和起飞测试,标志着我国舰载机技术获得重大突破。民机方面,C919客机研发工作稳步推进,已获得380架订单。直升机研制、生产能力取得长足进步。武直-10和武直-19的研制成功和先后列装,结束了我国没有专用武装直升机的局面,是陆军航空兵装备建设的重大成就;绝影-8型高速无人直升机也正在加速研制。民用直升机方面,中欧联合研制的直-15和AC313型直升机都取得重要进展;其中AC313是我国自行研制生产的唯一大型直升机,将填补我国大型民用直升机生产的空白,预计2013年将完成所有适航试飞项目,获得型号合格证,投入商业化运营。

  上述内容标志着我国飞机、直升机、无人机等航空专业领域的科学研究取得了较为全面的新突破。

  (二)航空动力方面

  航空动力是制造业中高新技术最集中的领域,整个制造过程对材料、工艺、加工手段、试验测试等都有极高的要求,而航空发动机技术则是高新技术中的尖端代表。近年来,我国发动机事业在过去50年技术积累基础上取得了较大的突破性进展。

  目前,我国新一代战斗机开始装备部队,与此相对应的采用进口俄罗斯发动机配套的局面正在改变。太行发动机是我国自主研制的大推力涡轮风扇发动机,20世纪80年代开始立项研制,2005年完成定型,已部分列装歼10、歼11,其多型改型正在用于新战机的动力国产化;为第四代战斗机及舰载机等配套的发动机也在研制之中。用于配套高级教练机的岷山发动机,用于配套通用飞机的九寨发动机均在研制中;秦岭发动机是70年代引进英国斯贝发动机的国产衍生型,经历材料、附件等的国产化,同时吸取了更多的先进技术对其进行改进、提升性能,已形成新的技术状态,并于2003年开始批量生产。昆仑发动机是沈阳发动机设计研究所按照国军标自行研制的第一台具有全部知识产权的中等推力加力涡轮喷气发动机,80年代开始研制,经过259项严格考核于2002年7月通过国家设计定型,可以满足歼7、歼8改进型推力增大的需求。

  (三)飞行力学方面

  近年来,我国针对先进飞行器设计的需要,在消化、吸收国外先进技术成果的基础上,通过自主创新、发展,在飞行力学理论、方法和技术研究中都取得了新的突破。

  非线性飞行动力学研究方面,近年来国内外在非定常气动力机理、实验研究方面开展了大量的工作,取得了一定的进展。尤其在风洞实验中,建立了模拟飞机单自由度运动、两自由度耦合运动的大振幅动态实验装置,获得了部分非定常以及耦合的气动数据,揭示出一些新的非定常非线性气动特性。研究表明,传统的气动模型已不再完全适用于描述大迎角过失速机动气动力。随着现代控制理论、智能控制的发展,非线性、非定常、多变量系统的辨识与控制的方法得到了极大的丰富。其中的理论成果也被从事风洞试验与飞行力学研究的工作者们引入了飞机大迎角状态气动建模领域。模糊逻辑、神经网络等新的方法在飞机大迎角状态气动建模中都得到了成功运用,获得了许多有益的成果。

  弹性飞行动力学研究方面,我国在弹性飞行器非定常气动力预测技术、弹性飞行器飞行动力学理论等方面开展了深入研究。如:发展了在时间域求解流场和结构耦合控制方程,从而精确预测结构做任意运动和变形下的非线性非定常气动力的CFD/CSD耦合计算方法;在弹性飞行器建模、耦合机理、稳定性、动响应等方面取得了具有国际水平的创造性研究成果,并形成了较为完善的理论和方法体系。

  非定常气动建模技术研究方面,为了使飞机在大攻角多自由度耦合运动中依然可控,具有争夺空战优势的能力,对飞机的大攻角及非定常动态气动特性进行了深入的研究。在大攻角大振幅非定常空气动力风洞试验的基础上开展了非定常气动力建模及空气动力数学模型构建。随着计算机水平的大幅提高,CFD技术已经被广泛地在各种工程中运用.近年来的气动弹性计算中也都逐渐采用了以跨音速小扰动方程、NS方程或Euler方程为基础的CFD技术来计算非定常气动力。

  此外,随着国内大型飞机和通用航空器的迅猛发展,民机飞行品质和适航性研究成为国内飞行力学的重要研究内容。我国多所研究机构开展了此方面的研究,系统地总结了飞机大迎角时的一些重要的非线性现象,研究了飞机非线性动态特性的各种方法以及近年来应用这些方法研究非线性动态特性方面所取得的成果;应用鲁棒控制技术解决了飞行中的一些控制问题;对于飞机在风切变中近地平飞情况,计算了最优闭环极点区;对于飞机在风切变中下滑着陆鲁棒控制系统,采用了改变加权阵法,在时域内进行了设计探索;对于多输入多输出系统也从理论上作了研究。

  (四)飞行试验方面

  我国对军用飞机新研型号设计定型试飞项目日益扩展,经多年积累和近年来大规模基础条件建设,已形成可承担与完成以下定型试飞项目的较为完善的试飞技术体系,包括:结构验证试验、飞行品质验证试验、飞行性能验证试验和阻力测量、推进系统验证试验、武器火控系统验证试验、设备系统验证试验、航空电子系统验证试验、电气系统验证试验、飞行控制系统验证试验、生存力/易损性验证试验、可靠性维修性测试性和保障性验证试验、直升机设计定型/鉴定试飞、新型号发动机设计定型/鉴定试飞,以及新研航空二级产品设计定型/鉴定试飞等。

  我国飞行试验机构已经可以进行空气动力学、飞行力学、结构完整性、动力装置和机载系统设备一般性的专题研究试飞和型号研制中所需的特定项目科研攻关试飞。在外部参数测量方面,我国已经基本能满足飞机起飞性能、着陆性能的测量和一般飞行轨迹及姿态的测量,且具有较高的测量精度。在机载测试系统方面,我国机载测试系统的性能指标已接近当今的世界先进水平。

  (五)制造技术方面

  中国“大飞机”项目的关键设备——我国自主研发的世界最大吨位模锻压机在中国第二重型机械集团公司德阳基地试生产成功,标志着我国金属材料制造技术有了新的突破。我国科研人员在吸收国外技术经验的基础上,针对我国航空飞行器复合材料的需求,完善和发展复合材料先进制造技术。此外,我国学者还开展了先进树脂基复合材料制造技术、非热压罐预浸料成型技术研究、复合材料热固化变形与补偿技术研究、航空用热压罐外固化预浸料复合材料的应用等研究,并取得一定的进展,为我国航空器需要的复合材料的制造加工提供了技术支持。在新支线飞机ARJ21的研制过程中,飞机制造厂充分发挥数字化异地设计/制造的优势,开展了设计/制造并行工程,全机设计100%采用CATIA三维数字化定义、数字化预装配和数字化样机技术;在ARJ21飞机的导管研制中也应用了数字化制造技术。

  目前,国家正大力推动航空发动机制造业的数字化进程,在关键零部件工艺设计、工装设计及数控加工中取得了明显的成效,推动了航空发动机制造业由传统的研制与生产模式向精益模式的转变。此外,2013年国务院向“飞机钛合金大型复杂整体构件激光成形技术”研发团队颁发了国家技术发明一等奖。这一技术在我国已经投入工业化应用,采用激光直接制造多种钛合金等大型复杂关键金属零件,已在目前研制的新型战机、大型运输机、C919大型客机等新机中应用;使我国成为继美国之后、世界上第二个掌握飞机钛合金结构件激光快速成形技术并实现工程应用的国家。

  (六)材料方面

  我国针对飞行器用钛合金材料开展了TC4、TC16、TC18、TC27、TB5、TB6、Ti55531、TC21、TC4-DT、TB8、Ti45Nb、TA15等钛合金材料研制及应用研究工作;开展了钛合金成分优化及大型铸锭熔炼、大规格棒材制备、锻坯组织及均匀性控制、大型整体锻件成形及热处理工艺、超声波探伤等研究工作;突破了高合金化铸锭成分均匀性控制、棒材及锻件组织性能均匀性控制、锻件批次稳定性控制等关键技术。针对发动机钛合金材料开展了Ti60、Ti6246、Ti6242、650℃钛合金和Ti40阻燃钛合金锻件的制坯、模锻成形、热处理、无损检测、机械加工、表面强化等应用研究,突破了锻件组织性能均匀性控制、零件机械加工及表面强化等关键技术,研制出高质量的发动机用高温钛合金锻件和关键部件。

  在特种/功能钛合金及特种工艺方面,主要开展了新型紧固件用钛合金材料、钛合金蜂窝材料、新型弹簧用钛合金材料、超低模量功能钛合金材料、SiC纤维增强钛基复合材料及其技术的研究;在先进树脂基复合材料方面,对先进热固性和热塑性树脂体系及复合材料、先进复合材料液态成型技术、非热压罐成型技术、结构/功能一体化复合材料和复合材料自动化技术等开展了研究;在金属基复合材料方面,对高性能连续纤维及其复合材料、结构/功能一体化的铝基复合材料和搅拌法制备的颗粒增强铝基复合材料及其精密铸造工艺技术等开展了研究;在陶瓷基复合材料方面,对功能复合陶瓷粉体的合成方法、自增韧氮化硅高温结构陶瓷材料、宽频透波陶瓷天线罩材料、陶瓷零件的凝胶注模精密成型技术和多用途薄壁形蜂窝陶瓷的挤出成型与制备技术等开展了研究;在材料性能测试与评价方面,对材料物理、化学性能表征,材料微观结构、性能与失效的理论和实验分析,以及液态成型工艺的数值模拟和在线检测开展了研究,并取得一定的进展。无机非金属材料在我国发展迅速,其新技术与新工艺不断得以应用与推广。尤其在高技术陶瓷材料、纳米材料、复合氧化物与化学传感器材料、特精细化学品材料和功能化合物材料,以及固体电解质方面发展迅速,无机非金属材料的产量也得到突破,无机非金属材料已经应用于我国航空航天领域,并在提升质量档次、精化品种规格的同时呈现出加速及扩展应用的良好前景。

  (七)机电系统方面

  我国飞机机电系统目前正向综合化、多电化和智能化方向发展,目标是实现功能、能量、控制和物理四个方面的全综合。我国正瞄准新一代飞机的需求,加快航空机电系统综合化控制和管理的研究,通过减少机电系统的互联方式和信息共享程度,提高综合化管理与诊断的能力,提升和完善其可靠性和可维修性。此外,我国在多电飞机先进供电技术、电气系统关键技术、多电系统故障诊断、电气负载管理研究、电源系统负载稳定性等方面开展了一系列研究,也开展了部分地面试验和飞行试验,验证了部分技术的成熟程度和可用性,证实了机电作动器取代液压作动器对飞机整体性能提升的贡献,为我国新一代飞行器多电化提供了初步基础。

三、本学科国内外研究进展比较

  虽然我国在总体、气动、结构、航空电子、航空机电等专业技术领域取得了长足进步。但是,与国外先进水平相比,我国航空科技仍然存在比较大的差距。

  与国外发达国家相比,我国的军民机发展不均衡,民用飞机具有市场竞争力的产品少,没有形成产品系列,绝大多数仅仅出口到亚非拉等第三世界国家。我国只掌握了中小型运输机技术,在掌握大型和超大型运输机技术方面还处于研发阶段,飞机的经济性、舒适性、环保性、使用保障性等方面还存在比较大的差距,综合技术还比较落后,动力系统方面的差距尤其明显。我国在飞行力学基础理论、技术方法方面,与欧、美、俄罗斯等航空发达国家相比,预先研究力量较薄弱,飞行力学顶层设计牵引作用欠缺,飞行力学大系统仿真与试验研究不够。飞行实验技术方面,缺乏前瞻性研究所需的试飞方法和手段,试飞技术创新能力明显不足。和发达国家相比,我国航空工业起步晚、科技实力弱,在部分领域尤其是民用航空器制造方面差距明显。材料方面,目前我国前沿材料研究滞后,新材料储备少,第三代、第四代航空产品所需的一些关键材料严重制约我国航空工业的发展。在航空机载系统领域,与国外相比我国在信息获取系统、航空通信系统、无线电导航等方面仍存在较大的差距。

四、本学科发展趋势及展望

  我国航空科技的发展具有良好的政治经济环境,但同时也面临严峻的国际竞争态势。为了加快航空工业的发展,促进创新型国家建设,发展航空科学技术工作必须立足于高新技术的战略布局,增强创新能力,带动技术进步,进而支持型号发展;应以市场可大规模应用的航空新产品研制为主线,统筹研发、产业化、市场开发与服务体系的协调发展;加快推进大型飞机研制,大力发展系列支线飞机、通用飞机和直升机;重点突破航空发动机瓶颈项目与技术,以及重要机载系统和关键设备,提高航空大部件、空中交通管理系统等的专业化生产能力,建立具有可持续发展能力的航空产业体系。

  此外,还应重点发展绿色航空技术、新航空系统技术、新一代直升机技术、先进气动布局技术、主动结构技术、自主控制与决策技术、高推重比/高功重比发动机技术、高性能复合材料技术、纳米材料与航空应用技术、故障预测和健康管理等技术。

Aeronautical Science and Technology

Aviation science and technology is a discipline with strong engineering characteristics. Its progress is closely linked with engineering achievements, and application particularly integrated ones are often reflected through them. This study analyzed progress in China’s aeronautical science and technology. The prospect, general trend and frontier in this field were presented through summarizing China’s aviation science and technology’s new progress, results, ideas, methods, technologies and comparing them with international advanced levels. Furthermore, suggestion on development direction was put forward.

18.1 Aircraft, helicopters and UAV

As for military aircrafts, the J-20 carried out validation flight test at Yanliang test center and the J-31 completed its maiden test flight on October 31, 2012, marking that China has become the second country which develops two kinds of fifth-generation aircraft at the same time after the United States. A heavy military transport aircraft developed by AVIC Xi’an Aircraft Industry (Group) Company is the largest military aircraft China has ever developed. The first J-15 prototype aircraft successfully went through landing and take-off tests on the Liaoning aircraft carrier, demonstrating breakthroughs in carrier–borne aircraft technology. As for civil aircrafts, C919 aircraft is developed steadily and has received 380 orders. As for military helicopters, great progress has been made in R&D and production capacity. WZ-10 and WZ-19 have been successfully developed and fielded, ending our embarrassment of lacking dedicated armed helicopters. It is a significant achievement in army aviation equipment. The development of JY-8, an unmanned high-speed helicopter, is accelerated. For civil helicopters, there are Z-15 jointly developed by China and EU and AC313. AC313 is the only large helicopter developed by China on its own so far. It’s expected that AC313 will complete all airworthiness flight tests, obtain type certification and be put into commercial operation in 2013.

18.2 Aerospace power

China continues to increase investment and has made steady progress and breakthroughs in aerospace power in 2013. As China’s troops began to equip with our own new generation fighters, the situation of using imported Russian engines is changing. Taihang engine, a high-thrust turbofan engine developed independently by China, was started in 1980s and finalized in 2005. It has been partially fitted out in the J-10 and J-11. Its polymorphic variants are being used for the localization of China’s new fighters. Engines for the 4th generation fighter aircraft and the carrier-borne aircraft are under development. The Minshan engine for the advanced trainer and Jiuzhai Engine for the general aviation aircraft are also under development. Qinling engine is a domestic derivate from the British-made Spey engine introduced in 1970s. It has reached a new technological level through localizing its materials, accessories, etc. and drawing more advanced technology. The mass production of it has begun in 2003. Kunlun engine is the first medium afterburner thrust turbojet in accordance with military standards developed by the Shenyang Engine Design and Research Institute independently. The institute owns full intellectual property right over it. Kunlun Engine Project was started in 1980s and got design finalization in July, 2002 after passing 259 rigorous assessments. It can meet the increasing thrust requirement of the improved J-7 and J-8.

18.3 Flight mechanics

In the field of nonlinear flight dynamics, many mechanism researches and experiments on unsteady aerodynamic were carried out both at home and abroad. Progress was made, especially in wind tunnel test. The experimental apparatus to simulate the large amplitude dynamic of the SDOF movement and two DOF coupled motion of the airplane were established, through which, some unsteady and coupling aerodynamic data were derived and some new nonlinear unsteady aerodynamic characteristics were found. With the development of modern control theory and intelligent control, the identification and control of nonlinear unsteady multivariable system has been greatly enriched. In the field of elastic flight dynamics research, our country has carried out profound researches on elastic aircraft unsteady aerodynamic prediction techniques and flight dynamics theory. In the field of unsteady aerodynamic modeling, in order to make the aircraft still be controllable in the large angle of attack state and DOF coupled motion so that it can gain advantage in an air war, we have carried out in-depth studies. With the substantial improvement of computer technology, CFD technology has been widely applied in a variety of projects. In addition, with rapid development of the domestic large aircraft and the general aviation aircraft, civil aircraft flying qualities and airworthiness have become an important part in flight dynamics research.

18.4 Flight test

The design finalization flight test program for newly-developed military aircrafts is expanding. We are now able to carry out the following items thanks to years of accumulation and large-scale infrastructure construction: structure verification tests, flying quality verification tests, flight performance verification and resistance measurements tests, the propulsion system verification tests, weapons fire control system verification tests, equipment system verification test, avionics system verification tests, electrical system verification tests, flight control system verification tests, survivability and vulnerability verification tests, reliability, maintainability and supportability verification tests, helicopter design styling and identification tests, the new model engine design styling and identification tests, the new research aviation two product design styling and identification tests and so on. A relatively complete flight test system has been formed. Our flight test agencies are competent for implementing not only flights to test general subjects like aerodynamics, flight mechanics, structural integrity, power plant equipment and airborne systems but also flights to test specific items required by scientific researches. In the aspect of external parameter measurements, our country has basically met the requirement for measuring the performance during takeoff and landing and general flight path and attitude with high precision. Besides, our airborne test system performance is close to today's world advanced level.

18.5 Manufacturing technology

The world’s largest tonnage forging presses, which was independently developed by China and serves as China’s “large aircraft” project’s critical equipment, was successfully produced by China National Erzhong Group Co., at its Deyang base, marking that China’s metal materials technology has made a new breakthrough. Researches on advanced polymer composites manufacturing technology, non-autoclave prepreg molding technology, deformation and thermal curing composites compensation technology, aerospace prepreg autoclave cured composite outer application were launched and progress has been achieved already. During the development of the new regional jet ARJ21, aircraft factories have made full advantage of the digitized offsite design and manufacturing. The whole machine design is with 100% CATIA three-dimensional digital definition, and digital pre-assembly and digital prototyping. Digital manufacturing technology has been applied in ARJ21’s pipe. Currently, the national aero-engine manufacturing industry is vigorously promoting the digitization process and has achieved a lot in the key components process design, tooling design and CNC machining. It helps facilitate the transfer from traditional development and production model to lean model. In addition, in 2013 the State Council has conferred first prize of State Technological Invention Award on the research team who has developed aircraft alloy integral member of large and complex laser forming technology. The technology has been put into industrial manufacturing in our country. Manufacturing a variety of titanium and other large and complex key metal parts directly through laser has been applied to new fighters, large transport aircrafts, large aircraft like C919, etc. which makes our country the second in the world that masters titanium aircraft structural parts laser rapid prototyping technology and realizes engineering application after the United States.

18.6 Materials

The development and application research of titanium alloys for aircrafts such as TC4, TC16, TC18, TC27, TB5, TB6, Ti55531, TC21, TC4-DT, TB8, Ti45Nb, TA15 were carried out. Key technology breakthroughs were made in high-alloyed ingot compositional uniformity control rods, forgings organizational performance uniformity control and stability control batch forgings. For the use of engine, the application researches of the forging, die forging, heat treatment, nondestructive testing, machining, surface hardening of Titanium alloy such as Ti60, Ti6246, Ti6242, 650 ℃ titanium and Ti40 Alloys were implemented. Key technologies of organization performance uniformity control, parts machining and surface hardening were derived. High-quality and high-temperature engine-use titanium alloy forgings and key components were developed. Special-function titanium and special technique, advanced polymer composites, metal matrix composites, the ceramic matrix composite materials, the material performance testing and evaluation were studied and progress have been achieved. The inorganic non-metallic materials are in rapid development and its new technology and technique are continuously applied and promoted

18.7 Aviation electromechanical systems

Our aviation electromechanical systems are moving towards integration, multilevel and intelligence. The goal is to achieve full integration of function, energy, control, and physics. To fulfill the requirement of China’s new generation aircrafts, China has accelerated researches on the aviation electromechanical systems integrated control and management, improved the comprehensive management and diagnostic capabilities by reducing the electromechanical system interconnect and information sharing, as well as enhanced its reliability and maintainability. In addition, China has carried out a series of studies on advanced more electric aircraft power supply technology, key electrical system technologies, multi-system fault diagnosis, electrical load management study, the stability of the power system load. China has also carried out some ground tests and flight tests to verify the technical maturity and usability of some technology and confirmed that the overall performance of the aircraft can be enhanced by replacing hydraulic actuators with electromechanical ones, which provides a preliminary basis for China’s new generation of more electric aircraft.

Although we have made considerable progress in aircraft overall design, aerodynamics, structure, avionics, and aviation electromechanical systems, we still lag behind the world advanced level. The development of China’s military and commercial aircraft is imbalanced. There are a few civil aircrafts with competitive edge, and no product family is formed yet. Most products are only exported to Asia, Africa and other Third World countries. China only masters the technology of medium and small transport planes. The technology of large and ultra-large transport aircraft is still in development stage. There are still large gaps in the aspect of aircrafts’ economy, comfort, environmental protection and supportability. The integrated technology is still backward, especially in power systems. In the field of flight mechanics, our preliminary research is weak, top-level design is insufficient, simulation and experimental study of large-scale systems is not enough comparing with Europe, America, Russia and other aviation developed countries. In the aspect of flight test technology, there is a lack of innovation and flight test means for prospective studies. Our aviation industry started very late with weak scientific and technological strength. There are too many backward areas, especially in the civil aviation manufacturing industry. In the aspect of materials, China’s research on cutting-edge materials lags behind and reserve of new materials is insufficient. The lack of some key materials for the third and fourth generation aviation products has seriously hampered the development of China’s aviation industry. In the field of aviation airborne systems, the gap between us and the foreign advanced level is large in terms of information retrieval system, aeronautical communication system, radio navigation and so on.

China’s aeronautical science and technology are faced with good domestic political and economic environment, but severe international challenges. In order to accelerate our aviation industry, construct China into an innovative country, develop aeronautical science and technology, China should adopt the pattern of driving sci-tech progress through model development to enhance innovation capability. It shall plan aeronautical technology R&D, industrialization, and market as a whole with largely-applied key products as the main line. It should also focus on accelerating the development of large aircrafts, regional jets series, general aviation aircrafts and helicopters. Breakthroughs shall be made in engine, important airborne systems and key equipments. Professional productivity for aviation large parts, air traffic management systems shall be improved. A sustainable aviation industry system shall be established. Furthermore, priorities should be given to the development of green aviation technology, new air system technology, new generation helicopter technology, advanced aerodynamic layout, active construction techniques, self-control and decision-making technology, high thrust to weight ratio and weight ratio engine technology, high power, high-performance composite materials technology, nano materials and aerospace applications technology, failure prediction and health management technologies.