Abstract:The research on the high-lift device of the laminar wing is of great significance for the drag reduction and noise reduction during flight. This article reviews the development needs of green aviation for drag reduction and noise reduction, introduces the technical characteristics of the high-lift device and laminar wing, and explains how the high-lift device on the leading and trailing edge of the laminar wing realizes the expansion of the laminar area. Introduce the structural adjustment methods, including the application of structural shapes, mechanisms and auxiliary devices. Analyze the technic that needs to be studied to achieve the adaptive adjustment of the high-lift device, and summarize the direction and ideas of the future research.

Abstract:The traditional airspace theory is faced with a series of problems such as the rapid growth of traffic density and the complex multi-class heterogeneity of the airspace controlled objects. Therefore, it is urgent to make research on the digital modeling of airspace and develop a new four-dimensional space-time framework of air traffic, then to launch a new collaborative management of airspace and air traffic flow on this basis. This paper focuses on the summary of the horizontal grid model and the three-dimensional airspace grid model, and surveys the research on the application of airspace grid method in air traffic management. On this basis, the research emphasis and development trend of the airspace gridding and digitalization are comprehensively analyzed. The research results aim to provide scientific guidance for the sustainable development of theory and application for airspace gridding and digitization.

Abstract:The application of Thermal Barrier Coatings (TBCs) is an effective means for gas turbines to reduce the surface temperature of hot-end components, restrain hot corrosion and obtain high thrust weight ratio. This paper first introduced the composition and structure of TBCs and then summarized three common failure modes such as erosion and foreign material damage, sintering oxidation and hot corrosion, and next the repair and remanufacturing methods of damaged and failed coatings at home and abroad were elaborated. finally, a series of problems and prospects were proposed.

Abstract:Wind energy is one of the most important ways for clean energy, and develops rapidly in recent years, which is pollution-free, renewable and readily available. Compared with the traditional low-altitude wind power generation, tethered floating wind power generation has a greater value and potential. There are a number of countries which have carried out relevant research and made many achievements. The research on the present tethered floating wind power generation technology is reported in this paper, which contains a conclusion of four kinds of tethered floating wind power generation technologies, an analysis of operating conception and technical feature, a discussion of critical points including design and manufacture of light and high strength tether, advanced envelope composite material, stable and intelligent control, aircraft overall design of efficient wind power generation and so on, as a foundation for future development and further research on this direction.

Abstract:Rotor airfoil design involves multi-point and multi-objective complex constraints. How to significantly improve the maximum lift coefficient and maximum lift-to-drag ratio of rotor airfoil is a fundamental problem to be solved urgently in the development of high-performance helicopter rotor blades in the future. Novel flow control technology is the most potential method to achieve the high lift enhancement and drag reduction of rotor airfoil. Based on the classic OA312 rotor airfoil, this paper conducts the low-speed wind tunnel test of high lift enhancement and drag reduction of rotor airfoil using Co-flow Jet concept (CFJ) with zero mass and high negative pressure at the leading edge. The rotor airfoil CFJ dynamometric model driven by the micro ducted fan group is designed. The influence of basic parameters such as the injection size, suction size and suction surface translation on lift enhancement and drag reduction is studied. The ratio of jet velocity to mainflow velocity is qualitatively discussed. The optimal value range of key parameters of CFJ rotor airfoil is given. Results show that compared with the OA312 baseline airfoil, the CFJ rotor airfoil can significantly reduce drag coefficients at low angle of attack, and even achieve while the zero-lift pitch moment is basically unchanged. The CFJ rotor airfoil can significantly increase the maximum lift coefficient and the stall angle of attack at high angle of attack. The maximum lift coefficient can be increased by about 67.5%, and the stall angle of attack is significantly delayed by nearly 14.8°. Research results verify the technical feasibility of applying CFJ technology to significantly improve the key performance of rotor airfoil and provide a new feasible solution and idea for the design of high-performance rotor blades in the future.

Abstract:At present, the standard of wake separation widely used in China is too conservative, which leads to the limitation of runway capacity. This article takes the approach aircraft wake encounter problem as the research object. On the one hand, it studies the approach wake safety separation reduction method to obtain the reduced critical wake separation. On the other hand, based on the PCA method to reduce the dimensionality of the aircraft performance data in the BADA database, a model hierarchical clustering method suitable for approach wake separation reduction is proposed. According to this method, new model classification results are obtained and constructed Reduced wake safety separation standards. The simulation results show that the model classification method used in this paper has good consistency with the mainstream classification methods at home and abroad, among the mainstream paired aircraft types at Huanghua International Airport, and the approach wake separation standard obtained in this paper can be reduced by more than 0.8km compared with the traditional wake separation standard.

Abstract:The safety operation support capability of air traffic mangement has a very important influence on the air traffic safety operation.Considering the fuzziness and randomness of various factors that affect the safe operation support capability of air traffic mangement, the cloud model theory is introduced to quantitatively evaluate the safe operation support capability of air traffic mangement.Based on the characteristics of safety operation management of air traffic mangement, the evaluation index system for safety operation support capacity is constructed.The queuing theory is used to assign weights to the evaluation indicators to overcome the influence of subjective factors on the weight assignment.By calculating the cloud digital characteristics of the evaluation index of the safety operation support capability of air traffic management by the reverse cloud generator, the evaluation cloud of the safety operation support capability is obtained.The application of the example shows that the cloud model can make an overall and accurate evaluation of safety operation support capability of air traffic management, and find out the main indicators that affect the safety operation support capability, which helps the air traffic management department take targeted measures to improve the safety operation support capability.

Abstract:Abstract：In this paper, viscoelastic damping materials and unidirectional glass fiber composite materials were used to make two kinds of constrained damping structures. The damping and mechanical properties of these two structures are studied. By finite element simulation study, the parameters of the constrained damping structure used on typical aircraft cantilever beam were designed and analyzed. The effects of the thickness of damping layer, the thickness of constrained layer and the size of the structure on the vibration response of the structure are studied. The constrained damping parameter law for cantilever beam structure is obtained. Vibration test experiment was designed based on the optimized parameters and the suppression effect of the constrained damping structure on the vibration response of the structure is verified.

Abstract:The effect of thermal load in the creep feed grinding have important effect on the surface quality for ma? chining the tenon teeth of turbine blade. In this paper，the effects of grinding parameters on grinding forces and temperature in grinding DD5 single crystal alloy are investigated by experiments. The influences and formation mechanism of DD5 creep-feed grinding forces and temperatures are analyzed，and a mapping model between thermodynamic effect and grinding parameters is established and verified. The experimental results show that the grinding depth has the greatest influence on the DD5 creep-feed grinding force and temperature，following by the grinding wheel speed，and the feed velocity of work-piece has less influence on the grinding forces and temperature. With the increase of the grinding wheel speed，the grinding force is decreasing，and the grinding temperature has an in?creasing trend. With the increase of feed velocity and grinding depth，both the grinding force and temperature are of increasing trends. Increasing the feed velocity and reducing the grinding depth on the premise of satisfying the material removal rate can avoid the larger grinding thermodynamic coupling layer on the DD5 grinding surface.

Abstract:Improving future performance is the key to airport sustainable development. Accurate forecast is the basis for improving performance. Considering the impact of COVID-19, a combination method with quantitative and qualitative analysis are used to forecast the performance of 10 Asian hub airports during 14th 5-Year, and puts forward strategic suggestions for airport sustainable development. It is found that grey model quantitative analysis method is more suitable to forecast airport performance than ARIMA; Comparing the predicted values of the eight airports with the actual statistical values from 2016 to 2019 (Pudong and Bao'an airports from 2017 to 2020), it is found that all the forecast errors are less than 4%, and the forecast results are good; Baiyun Airport passenger throughput will continue to maintain the first in Guangdong, Hong Kong and Macao bay area; In 2025, Incheon Airport will become the first Asian passenger transport hub for the first time; Hong Kong Airport will maintain the first Asian cargo throughput; Incheon Airport will become the first financial performance Asian airport; In 2024, Baiyun Airport will become the first financial performance airport in mainland China. It is suggested that mainland Chinese airports should attach importance to the innovation of nonaeronautical services, enhance airport financial performance, develop airport economy and promote sustainable development.

Abstract:The freeplay of control surfaces is one typical type of structural nonlinearity, which is caused by design, manufacture, assembly, etc. It may easily lead to the limit cycle oscillation (LCO). LCO usually shows equal amplitude vibration, and it may influence the integrity of structure and cause structural failure if the amplitude is too large. Nonlinear flutter analysis method in time domain for control surface with freeplay is investigated and used to compute the nonlinear flutter result of certain aircraft. The result is compared with that achieved by frequency domain method. The comparison shows good compliance regarding critical flutter velocity and frequency. The time-domain method can precisely predict the LCO critical velocity. The method can also be proof of compliance with airworthiness standards．

Abstract:The nose landing gear generally has a bilateral symmetrical doors which are different from the main landing gear. The nose landing gear door opened when the civil aircraft enters the landing must interfere with the flow field and noise of the landing gear and reflect. In order to study the interference blocking effect of the nose landing gear door on the landing gear flow field and noise, firstly, a two-wheel landing gear model is used to confirm IDDES(Improved Delayed Detached Eddy Simulation) method and the FW-H(Ffowcs Williams-Hawkings) equation. On the basis of the accuracy and reliability of the numerical method, the flow field characteristics and far-field noise characteristics of the two models of the high-fidelity nose landing gear of a civil aircraft with and without doors are compared and analyzed. The flow evolution process near the doors and the influence of the doors on the far-field radiated noise are analyzed and studied. The calculation results show that because the windward face of the door is not straight, but slightly bends inward and has a certain angle with the free stream flow, it causes the local flow separation at the front of the doors, and then spreads to the whole area between the doors. At the same time, the doors on both sides block the trend of interference airflow spreading to the side of the cavity and impact the side edge of the cavity, block the pressure wave produced by the landing gear, weaken the sideline noise of the landing gear and form the phenomenon of acoustic interference.

Abstract:Payload calculation and corresponding payload platform development are important steps in the design and development of a UAV. Because an accurate payload calculation can ensure that the structural load bearing and the force transmission of the airframe is reasonable, and achieve the lightweight design goal of the UAV airframe. In this paper, we propose a method for flight load calculation considering inertial loads, which is based on a fluid grid computing unit to study the in-cell flight load algorithm. Then a platform for developing UAV loads is written based on the method. Finally, the method and the development platform are verified to be reasonable and correct by some data, and have been successfully applied in the design process of a certain high-speed aircraft.

Abstract:Carbon fiber reinforced polymer (CFRP) is widely used in the design of aircraft fuselage panel, it is important to study the buckling and failure characteristics of panel to improve the efficiency of structural design. The compression buckling load, failure mode and failure load of composite cap-stiffened panel under compression load are studied by analysis and panel test. The buckling modes and loads of panels under compression are studied by engineering method and finite element method. The loading capacity of the panel under compression load is studied by the column instability method modified by von Karman method. Based on the advanced multi-load panel test rig, the 3m×2m panel test are completed under compression load and pressure load. the analysis methods are verified and modified by test. The results show that the engineering analysis and finite element method need to be modified in buckling analysis, and the results of the modified column instability method are slightly conservative than the test results.

Abstract:Abstract： It is the fact that the complicity of structural details and loading conditions makes a great challenge of metal structure design. One of the most important aspects is to numerically predict the metal yield and failure behavior under complex stress state in a high accuracy. However, experimental results have revealed that the traditional von Mises criterion can not accurately predict yield behavior of metal under complex stress states. In order to improve the accuracy, a yield criteria modified by stress state parameters of triaxiality and Lode angle is proposed in this paper. Then modified yield criteria is implemented into ABAQUS/explicit with VUMAT user’s subroutine and applied to numerical analysis of 2024-?T4 coupons. Numerical and experimental results show that the proposed yield criterion can improve the prediction accuracy of metal yield under complex stress state then traditional von Mises criterion.

Abstract:To investigate the performance of combustion and flow characteristics of four-duct-annular advanced vortex combustor with flow guide vanes, the effects of different structure parameters of the flow guide vanes on flow fields, structure of vortices, the total pressure loss, combustion efficiency were numerically analyzed. The results show that the stable dual vortices structure is formed in the cavity, the stability of flame and the mixing of gas in the cavity are enhanced and the combustion efficiency is greatly increased. The structure parameter a/E influences the performance of the combustor significantly. With the increasing value of a/E, the combustion efficiency increases significantly, but the total pressure loss coefficient also increases simultaneously. When the value of b/H increases, the combustion efficiency and total pressure loss coefficient decrease simultaneously. The combustion efficiency and total pressure loss coefficient decrease first and then rise slightly with the increasing value of c/E. When a/E=0.3, b/H=0.4, c/L=0.2, the best characteristic of the combustor is achieved with the combustion efficiency 98.56%, the total pressure loss coefficient 3.194%.

Abstract:Aiming at the problems such as high frequency of airspeed anomalies, multiple fault types, great impact on flight safety, and heavy burden of pilots’ disposal after airspeed anomalies, this paper designed an auxiliary decision-making function for airspeed anomalies of large aircraft. Under different flight phases and aircraft performance, the residual voting judgment, flight status conformity judgment, airspeed reconstruction algorithm based on wind speed and airspeed reconstruction algorithm based on lift equation are designed are respectively studied. Taking the DaYun large aircraft as an example, the simulation results show that the method is effective.

Abstract:FOD (Foreign Object Debris) refers generally to a certain type of foreign substances that may damage aircrafts or air systems, Currently, FOD monitoring in the vast majority of airports across the world is operated manually. To meet the urgent need for FOD monitoring measures, the imaging technology based on arc synthetic aperture (ArcSAR) is researched, the geometrical model and signal model of ArcSAR are built, and the method described in this paper increases the detection range to the same target by 2~3 times and can effectively inhibit “flickering” clutters such as rain and snow.

Abstract:Aviation dc contactor because of its small volume load characteristics such as high reliability, long life, each big system is widely used in aircraft electric parts, is of great importance in modern aircraft electrical control unit air dc contactor in the process of opening and closing, the contact will get electrical erosion when erosion after reaching a certain degree, dynamic and static contact will be welded together, contactor will be out of control and important system fault in the aircraft power supply, etcBased on the fault analysis of a starter contactor of a certain type of aircraft, and combining with the average fault rate of the contactor in the past four years, the Suggestions on the timely control management of the component are put forward, which can effectively prevent the occurrence of major faults of other aircraft systems caused by the fusion welding of contactor.

Abstract:Accuracy of airborne radar antenna servo control(ARASC) is one of important index for radar system precision search, identification and detection. Radar antenna was dropt and scan movement, because of wind speed and movement speed of carrier, making radar antenna recived more atmosphere resistance, atmosphere resistance was ceaseless change along with time and different angle of scan movement, it would be bring additive load distubance torque to ARASC. In order to controlling disturbance for accuracy of ARASC influence, improving ARASC movement preiciosn, ARASC disturbance observer(DOB) solving schene was put forward. ARASC dynamic model and servo control model were set up,additive load torque chose by atmosphere resistance was import to input end of controoled object for putting up compensate, according to improving accuracy in fact environment. Moeding simulation and expeerimentation analysis were put up with different wind speed influence,simulation experimentation show ARASC accuracy based on disturbance observer is better.