英法联手开展无人作战飞机研发

英国国防大臣菲利普·哈蒙德与法国国防部长让-伊夫·勒德里安于7月15日在范堡罗航展签署了一项协议,决定于今年10月正式启动一项为期两年的“未来作战航空系统”（FCAS）的可行性研究。此举标志着两国在20世纪60年代合作研制“协和”超声速客机后,时隔半个世纪在航空航天工业领域重启密切合作的新时代。     

基于MATLAB/Simulink的飞机燃油箱内燃油温度仿真计算

燃油温度是飞机燃油箱可燃性评估的关键参数之一。为了研究飞机燃油箱内温度的分布规律及传热模型的正确性,采用MATLAB/Simulink软件平台搭建出了客机的燃油箱热仿真模型。在输入飞行实验所对应的的边界条件后,通过数值模拟获得燃油箱内部各计算节点处的燃油温度。结果表明,在三种不同的航行条件下,燃油箱热模型仿真结果均能较好地与飞行实验结果吻合,能够将计算误差控制在一定范围内。采用该燃油箱热模型进行热仿真数值模拟可以获得较为准确的飞机燃油箱热特性,能够在飞机设计阶段,用于对燃油箱结构以及内热源部件布置的优化。     

Multi-objective optimization of aircraft design for emission and cost reductions

Pollutant gases emitted from the civil jet are doing more and more harm to the environ- ment with the rapid development of the global commercial aviation transport. Low environmental impact has become a new requirement for aircraft design. In this paper, estimation method for emis- sion in aircraft conceptual design stage is improved based on the International Civil Aviation Orga- nization （ICAO） aircraft engine emissions databank and the polynomial curve fitting methods. The greenhouse gas emission （CO2 equivalent） per seat per kilometer is proposed to measure the emis- sions. An approximate sensitive analysis and a multi-objective optimization of aircraft design for tradeoff between greenhouse effect and direct operating cost （DOC） are performed with five geom- etry variables of wing configuration and two flight operational parameters. The results indicate that reducing the cruise altitude and Mach number may result in a decrease of the greenhouse effect but an increase of DOC. And the two flight operational parameters have more effects on the emissions than the wing configuration. The Pareto-optimal front shows that a decrease of 29.8% in DOC is attained at the expense of an increase of 10.8% in greenhouse gases.     

Flutter analysis of an airfoil with nonlinear damping using equivalent linearization

The equivalent linearization method （ELM） is modified to investigate the nonlinear flut- ter system of an airfoil with a cubic damping. After obtaining the linearization quantity of the cubic nonlinearity by the ELM, an equivalent system can be deduced and then investigated by linear flut- ter analysis methods. Different from the routine procedures of the ELM, the frequency rather than the amplitude of limit cycle oscillation （LCO） is chosen as an active increment to produce bifurca- tion charts. Numerical examples show that this modification makes the ELM much more efficient. Meanwhile, the LCOs obtained by the ELM are in good agreement with numerical solutions. The nonlinear damping can delay the occurrence of secondary bifurcation. On the other hand, it has marginal influence on bifurcation characteristics or LCOs.     

Aeroelastic two-level optimization for preliminary design of wing structures considering robust constraints

An aeroelastic two-level optimization methodology for preliminary design of wing struc- tures is presented, in which the parameters for structural layout and sizes are taken as design vari- ables in the first-level optimization, and robust constraints in conjunction with conventional aeroelastic constraints are considered in the second-level optimization. A low-order panel method is used for aerodynamic analysis in the first-level optimization, and a high-order panel method is employed in the second-level optimization. It is concluded that the design of the abovementioned structural parameters of a wing can be improved using the present method with high efficiency. An improvement is seen in aeroelastic performance of the wing obtained with the present method when compared to the initial wing. Since these optimized structures are obtained after consideration of aerodynamic and structural uncertainties, they are well suited to encounter these uncertainties when they occur in reality.     

基于ANSYS的机翼动力学分析

针对无人机在挂载导弹飞行和发射导弹时,无人机机翼由于受到多种载荷影响所产生的应力应变,应用ANSYS软件动力学分析,计算模拟了机翼在受到多种载荷影响时所产生的应力分布和应变量。分析结果表明,由于外挂物重量和机翼周围气动流场的影响,机翼会产生不同程度的颤振和扭转,其研究结果对合理设计机翼结构具有一定的参考意义。     

飞机客舱烟气扩散数值仿真

通过建立五排客舱的几何模型及客舱烟气流动的数值仿真模型,采用RNG k-ε湍流模型对客舱内的湍流流动进行描述。基于Fluent对火灾阴燃阶段客舱内烟气浓度场和温度场进行三维数值模拟分析,预测了烟气浓度随时间变化规律。结合适航规章分析烟气中CO、CO2浓度对客舱空气品质及乘客健康安全的影响,给出火灾紧急措施建议,同时也为大型运输类飞机烟雾的适航审定符合性验证方法的研究提供基础。     

飞机融资租赁的若干影响因素——爱尔兰飞机融资租赁的发展

<正>2007年3月,中国银监会发布《金融租赁公司管理办法》,允许银行设立金融租赁公司从事融资租赁业务,中国的融资租赁市场迎来了新的转折。这些银行系的金融租赁公司虽然绝对数量较少,截止目前只有12家,但是因为其优厚的发展条件,自成立起迅速成为中国租赁市场上的主导力量,尤其在飞机、发动机、船舶等大型高价值资产的租赁方面领跑中国租赁市场。随着首批获批的金融租赁公司迎来成立五周年纪念日,国内的法制、税收、会计和监管等大环境对     

民用运输类飞机型号豁免要求研究

<正>本文对型号豁免的定义和各适航当局的相关规定及要求进行了对比分析,并对A340、A380和B747系列型号所批准采用的豁免情况进行了分析研究,可为国内民机型号的豁免申请提供参考。豁免是指在民用飞机型号合格审定中,申请人可以由于技术原因向适航当局合格审定部门申请暂时或永久免除适航规章和环境保护规章中的某些条款。根据该定义知豁免包括两种类型:暂时豁免和永久豁免。豁免是构成民用运输类飞机型号合格审定基础的四个要素之一,其他三个要素包括适用的航空规章(适航规章25部、环境保护规章34部和36部、运行规章91部和121部)、专用条件和等效安全。这些要素均需在最终获得批准的型号合格证数据单     

冬季航空器的除防冰

<正>中国民航局对飞机带有冰雪霜起飞有严格限制,CCAR-121部第121.649条进行了明确规定。为了保证飞行安全,必须对航空器有效地开展除防冰工作。笔者结合自己除防冰工作的亲身经验,谈谈对航空器除防冰工作的思考。一、航空器除防冰程序流程图(见图1、图2)二、航空器除防冰中的常见问题分析问题一:CCAR-1 21.649中“地面结冰条件下的基本要求”第3款规定,确定飞机是否存在冰冻污染物的最终责任人是机长,而CCAR-121.649中“航空器在结冰条件下运行”(b)款规定,当有霜、雪或冰附着在飞机机翼、操纵面、螺旋桨、发动机进口或者其他重要表面上,或者不能符合本条(c)款时,任何人不得使飞机起飞。上述两个条款是否有矛盾?早晨常有霜附着在飞机上面,但少数飞机就不除霜,机长认为没有必要除。