直升机旋翼桨叶防/除冰技术新思路

为了满足直升机全天候飞行和特殊环境中飞行的要求,有必要对直升机的旋翼桨叶、发动机进气道、风挡玻璃等部位采取防/除冰防护。常用的电热等防/除冰方法存在各种弊端,如消耗大量电能、冰防护装置复杂、脱冰产生危害等,而超疏水表面材料以零耗能、零设备、零操作的特点在防/除冰方面具有巨大的应用潜力。本文在总结现有防/除冰方法及其特点的基础上,介绍了超疏水表面材料的最新研究进展,探讨了其在直升机防/除冰技术上应用的可能性,为解决直升机的防/除冰问题提供了一个新思路。     

Study on the lift and propulsive force shares to improve the flight performance of a compound helicopter

To investigate the effects of lift and propulsive force shares on flight performance, a compound helicopter model is derived. The model consists of a helicopter model, a wing model and a propeller model. At a low speed of 100 km/h, the Lift-to-Drag ratio(L/D) of the compound helicopter is improved when the wing provides 20.2% of the take-off weight. At high speeds, the L/D can be improved when the propeller provides the total propulsive force. Lowering the main rotor speed increases the wing lif...     

Mass and performance optimization of an airplane wing leading edge structure against bird strike using Taguchi-based grey relational analysis

Collisions between birds and aircraft are one of the most dangerous threats to flight safety. In this study, smoothed particles hydrodynamics (SPH) method is used for simulating the bird strike to an airplane wing leading edge structure. In order to verify the model, first, experiment of bird strike to a flat aluminum plate is simulated, and then bird impact on an airplane wing lead-ing edge structure is investigated. After that, considering dimensions of wing internal structural components like ribs, skin and spar as design variables, we try to minimize structural mass and wing skin deformation simultaneously. To do this, bird strike simulations to 18 different wing structures are made based on Taguchi’s L18 factorial design of experiment. Then grey relational analysis is used to minimize structural mass and wing skin deformation due to the bird strike. The analysis of variance (ANOVA) is also applied and it is concluded that the most significant parameter for the performance of wing structure against impact is the skin thickness. Finally, a validation simu-lation is conducted under the optimal condition to show the improvement of performance of the wing structure.     

可重复使用运载器机翼外形优化

研究了有翼可重复使用运载器机翼平面外形参数优化设计问题。在高超声速配平和低速水平着陆性能等约束条件下，利用混合遗传算法和粒子群优化算法来选择最优机翼外形参数，使机翼重量最小化。在已知的不同质心位置下求得相应的最小重量机翼外形。亚声速气动力采用面源法计算，高超声速气动力采用修正的牛顿流理论计算。为了降低计算耗费，使用均匀设计和逐步回归方法建立了低速气动力回归模型。整个优化过程在Matlab集成环境下完成。     

Static strength analysis of dragonfly inspired wings for biomimetic micro aerial vehicles

This article examines the suitability of fabricating artificial, dragonfly-like, wing frames from materials that are commonly used in unmanned aircraft(balsa wood, black graphite carbon fiber and red prepreg fiberglass). Wing frames made with Type 321 stainless steel are also examined for comparison. The purpose of these wings is for future use in biomimetic micro aerial vehicles(BMAV). BMAV are a new class of unmanned micro-sized aerial vehicles that mimic flying biological organisms(like flying insects). Insects, such as dragonflies, possess corrugated and complex vein structures that are difficult to mimic. Simplified dragonfly-like wing frames were fabricated from these materials and then a nano-composite film was adhered to them, which mimics the membrane of an actual dragonfly. Finite element analysis simulations were also performed and compared to experimental results. The results showed good agreement(less than 10% difference for all cases).Analysis of these results shows that stainless steel is a poor choice for this wing configuration, primarily because of the aggressive oxidation observed. Steel, as well as balsa wood, also lacks flexibility. In comparison, black graphite carbon fiber and red prepreg fiberglass offer some structural advantages, making them more suitable for consideration in future BMAV applications.     

Computational study of wing deformation and sting interference effects with the CAE-AVM test case

A modern transonic computational fluid dynamics test case is described in this paper, which is the Aerodynamic Validation Model (AVM) from the Chinese Aeronautical Establishment (CAE). The CAE-AVM is a representation of a modern transonic business jet aircraft with a design Mach number of 0.85. Numerical simulations for the AVM are conducted for two geometries: one baseline geometry, and one geometry that includes the applied model support system of the wind tunnel as well as the deformed wing shape that occurred during wind tunnel testing. The combined influence of wing deformation and model support interference on local and integral aerodynamic features is presented. Comparisons between CFD and experimental results are made; reasons of discrepancy between results from considered cases are analyzed.     

Blank Panel Design of Integral Wing Skin Panels Based on Feature Mapping Methods

A blank panel design algorithm based on feature mapping methods for integral wing skin panels with supercritical airfoil surface is presented.The model of a wing panel is decomposed into features,and features of the panel are decomposed into information of location,direction,dimension and Boolean types.Features are mapped into the plane through optimal surface development algorithm.The plane panel is modeled by rebuilding the mapped features.Blanks of shot-peen forming panels are designed to identify the effectiveness of the methods.     

An experimental study of elastic properties of dragonfly-like flapping wings for use in biomimetic micro air vehicles (BMAVs)

This article studies the elastic properties of several biomimetic micro air vehicle (BMAV) wings that are based on a dragonfly wing. BMAVs are a new class of unmanned micro-sized air vehicles that mimic the flapping wing motion of flying biological organisms (e.g., insects, birds, and bats). Three structurally identical wings were fabricated using different materials: acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and acrylic. Simplified wing frame structures were fabricated from these materials and then a nanocomposite film was adhered to them which mimics the membrane of an actual dragonfly. These wings were then attached to an electromagnetic actu-ator and passively flapped at frequencies of 10–250 Hz. A three-dimensional high frame rate imag-ing system was used to capture the flapping motions of these wings at a resolution of 320 pixels × 240 pixels and 35000 frames per second. The maximum bending angle, maximum wing tip deflection, maximum wing tip twist angle, and wing tip twist speed of each wing were measured and compared to each other and the actual dragonfly wing. The results show that the ABS wing has considerable flexibility in the chordwise direction, whereas the PLA and acrylic wings show better conformity to an actual dragonfly wing in the spanwise direction. Past studies have shown that the aerodynamic performance of a BMAV flapping wing is enhanced if its chordwise flexibility is increased and its spanwise flexibility is reduced. Therefore, the ABS wing (fabricated using a 3D printer) shows the most promising results for future applications.     

民用航空发动机进气道防冰功率的计算方法研究

根据民用航空发动机短舱防冰系统设计的要求,对进气道的防冰功率进行了的计算研究.基本思路是利用结冰数值计算软件计算进气道水滴撞击范围,在此基础上,根据进气道防冰表面不同温度的要求,确定了进气道防冰系统引气功率的需求.提出的发动机进气道防冰功率计算方法,可供民用航空发动机短舱进气道防冰系统设计参考和借鉴.     

基于疏水功能表面的飞机防覆冰机理研究进展

如何规避飞机结冰产生的飞行安全隐患一直是航空领域的重要问题。近年来,疏水材料表面被动防覆冰概念被提出并快速发展起来。首先介绍了在液滴冲击阶段防止表面结冰的机理及方法,系统综述了包括减少水滴与表面接触时间以及减少冰核形成时间的研究方案。又进一步介绍了液滴结冰后的防覆冰机理,综述了通过优化疏水表面性能及微纳结构形貌减小冰黏附力的研究进展。最后对疏水表面防覆冰的发展趋势进行了展望。