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Table of Content

    19 December 2024, Volume 42 Issue 1
    Review of studies on load balancing problem in civil aviation transportation
    ZHAO Xiangling , ZUO Lei , LI Yunfei , XU Jihui
    2024, 42(1):  1-9. 
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    In order to understand the current development level and research progress of aircraft weight and balance (AWB), and provide reference for the subsequent research and application of loading technology, the concept of weight, center of gravity(CG) and center of gravity envelope is introduced firstly. Secondly, three research directions of air cargo loading are summarized, including cargo transportation planning, cargo packing, container loading balance.

    And container loading balance is divided into heuristic method and (mixed) integer linear programming method according to the time process. Then, the development and application status of the loading technology are intro鄄 duced, the development process of the AWB are summarized and analyzed, and the application of the loading technology is divided into three stages of manual AWB, computer-aided AWB and automatic AWB. Through the literature review, it is found that the recent research on loading adopts the simplified target center of gravity devia鄄 tion constraint, resulting in a large gap between the research and the practical application. Finally, the prospect of the loading technology is proposed, stating that the future loading technology will be based on the actual center of gravity envelope, transitioning from the enumeration method to the integer planning method, gradually achieve loading optimization, and integrate machine learning and other technologies into company preferences and operat鄄 ing experience to achieve intelligent loading scheme belongs to airline preferences.

    Power spectrum of DME signal and its leakage power in adjacent channel
    LIU Haitao, LIU Li, WANG Lei, LI Dongxia
    2024, 42(1):  10-15. 
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    To solve the problem of spectrum resource scarcity in aeronautical data link, L-band digital aeronautical communi- cations system (L-DACS) will be deployed as an inlay system in the spectral gaps between channels of the distance measuring equipment (DME). Therefore, it′s unavoidable that the DME signal has a severe influence on the perfor- mance of L-DACS system receiver. To analyze the influence of out-of-band leakage of DME/N (distance measure equipment/normal) and DME/P (distance measure equipment/precision) signal on L-DACS system receiver, the mathematical models of DME/N and DME/P signal are established, firstly. Then, the expressions of power spectral density of DME/N and DME/P signal are theoretically derived. Based on these expressions, the effect of out-ofband leakage of DME/N and DME/P signal on L-DACS receiver, which is deployed in adjacent channel, are researched. Finally, the correctness of the theoretical analysis results is verified through computer simulation. The results show that the impact of out-of-band leakage of DME signal on L-DACS system is mainly manifested in the first adjacent channel, and the leakage power of DME/P signal in the first adjacent channel is 10 dB higher than that of DME/N signal.
    ACARS function activation method of VHF airborne radio
    YUE Meng a , HONG Xueting b , JIANG Yiyang b , ZHENG Han b
    2024, 42(1):  16-23. 
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    Aircraft communication addressing and reporting system (ACARS) is currently the most widely used air-ground da鄄
    ta link communication system worldwide. In order to activate the ACARS function of real aviation material, a typical
    very high frequency (VHF) airborne radio Collins VHF-2100 is selected, and the activation method of ACARS
    function is designed from three aspects of interface specifications, data interaction timing relationship and electrical
    connection characteristics. Through the verification of experiment platform, the test results indicate that the de鄄
    signed method can configure the VHF-2100 airborne radio, and enable it to receive and send ACARS message. The
    activation of actual aviation material verifies the feasibility of interface control, and provides a certain reference for
    the localization of ACARS airborne radio.
    Effects of acid treatment on the catalytic synthesis of clean and efficient fire extinguishing agent CF3I by KF/AC#br#
    ZHOU Xiaomeng , REN Liheng , PENG Zhimin, , WANG Gang, , CHEN Wensheng, , LIU Jian , YAN Hao
    2024, 42(1):  24-29. 
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    In order to explore the effects of different acid treatments on catalytic performance during catalyst preparation, and
    reduce the production cost of trifluoroiodomethane (CF3I) to promote its application as a fire extinguishing agent in
    the field of civil aviation, inorganic acids (HNO3, HCl, H2SO4) and organic acids (CH3COOH, CF3COOH, C6H8O7)
    were used to pretreat activated carbon (AC), and a series of KF/AC catalysts were prepared using the treated AC as
    a carrier. The catalytic synthesis performance under the same operating conditions was measured by CF3I yield.
    The results showed that both inorganic acid and organic acid treatment will increase the AC micropore volume, ex鄄
    cept for citric acid (C6H8O7). Different acid treatments will increase the number of carboxyl groups on the AC sur鄄
    face and alkaline sites of catalyst. The microporous loading of K played a key role in the performance of catalysts.
    Organic acid treatment can increase the microporous loading to three times more than that of untreated catalysts,
    and the effect was significantly better than that of inorganic acid treatment. The treatment with trifluoroacetic acid
    (CF3COOH) showed the most significant improvement of the catalytic performance.
    Dynamic modeling and analysis of engine blade-hard coating damping structure under high temperature environment#br#
    LI Shuangbaoa , LI Fangb
    2024, 42(1):  30-39. 
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    Hard coating is a kind of damping structure can effectively restrain harmful vibration of engine blade, and its dynamic research is of paramount significance for the design and optimization of composite structure. The dynamic model of engine blade-hard coating damping structure under high temperature environment is discussed, and conducts dynamic analysis on it to study the dynamic characteristics such as inherent frequency, vibration response amplitude, etc. The numerical simulation is adopted to analyze the impact of hard coating and temperature on dynamic characteristics of composite structure. The finite element simulation is adopted for verification of results to conclude that the hard coating can reduce vibration of engine blade, which is still effective under high temperature environment.
    Simulation of airport passenger security check process based on multi-queue
    ZHAO Zhenwu, ZHENG Wenyue, ZHANG Chenchen
    2024, 42(1):  40-46. 
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    In order to improve the current situation of airport passenger security check, six kinds of queuing methods of security check verification service desk were proposed based on queuing theory without changing the physical pattern of security check. According to the security check layout and space size of a certain airport, an airport passenger security check process model was constructed in the AnyLogic software based on the social force model. Six kinds of queuing methods were simulated based on the passenger arrival rates of 402 people/h, 623 people/h, and 802 people/h during low, medium, and peak hours. Four performance indicators were obtained to measure the efficiency of security check, including total security check time, average number of people in a single queue, average waiting time for passengers, and average service time of security check. It was found that the queuing method of one-to-one type with the verification service desk far away from the security check channel performed better. Comparing the performance indicators of the validation service desk being placed every 1 m away from the security channel by 120 m, the results showed that one-to-one type with the verification service desk being 20 m away from the security channel and the S-shape queue was more suitable for the current need of airport passenger security check.
    Design of asymmetric 12-pulse auto-transformer rectifier unit
    ZHANG Jianfang, HAO Xiaohong
    2024, 42(1):  47-52. 
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    To meet the industry application requirements of miniaturization and lightweight for multi pulse auto-transformer rectifier (ATRU), a design scheme of asymmetric 12-pulse ATRU was proposed in this paper. Firstly, the topology and winding structure were elaborated in detail. Secondly, the main performance parameters such as input current harmonics and equivalent capacity were analyzed and validated through Saber simulation. Finally, a 10 kW ATRU prototype was designed based on this, and the actual measured data analysis was conducted on the prototype. The analysis results showed that the design scheme can meet the requirement of DO-160 standard, and the equivalent capacity was smaller compared to that of symmetric 12-pulse ATRU, which was more in line with the design requirements of miniaturization and light weighting of aviation products.
    Dynamic behavior characteristics of droplet impacting on random rough surface
    CHEN Fei a , HUO Jinjianb , WANG Liwenb , TANG Jieb
    2024, 42(1):  53-58. 
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    During the cleaning process of aero-engine, the engine online washing is realized by the impact of cleaning droplet and blade fouling. Therefore, the research on the impact, spreading and infiltration of droplet on random rough surface is of great significance for improving the cleaning effect of engine online washing. In order to obtain the impact characteristics of the droplet impacting on random rough surface, the dynamic behavior of impacting, spreading and infiltrating of the cleaning droplet on random rough surface is studied. The effects of droplet diameter and impact velocity on the impact characteristics are analyzed stressfullly. The results show that, compared with the smooth wall, due to the effect of wall roughness, many broken small droplets will be generated at the spreading edge of the droplet, and the bulge and gap of the rough structure will cause bubbles in the gap, which affects the infiltration effect. The spreading diameter of droplet is positively correlated with droplet diameter and impact velocity, which helps to offset the droplet splash caused by wall roughness. The infiltration degree of the wall increases with droplet diameter and impact velocity, while the impact velocity has little effect on the infiltration degree of the core area. The research results in this paper can provide a certain theoretical basis for optimizing the parameters of aero-engine online washing process.
    Fatigue damage pattern and microstructure study of ECC
    CAI Jinga , LIU Hanlei a , HUO Haifenga , ZHI Yanfei b , REN Yanlongb
    2024, 42(1):  59-64. 
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    In this paper, the uniaxial tensile cyclic loading test was carried out on engineered cementitious composites (ECC) specimens using a fatigue testing machine to investigate the fatigue pattern and the damage reason of the ECC.

    The results show that the damage pattern of ECC specimens is related to its cumulative axial deformation rate. At the initial stage of loading, the cumulative axial deformation amplifies significantly with the number of cyclic loads increasing, and then enters a stable deformation phase. Further loading will result in a rapid increase of the cumulative axial deformation and eventually leads to fracture of the specimen. The crack width of ECC development, shows a trend of low in the middle and high at both ends. ECC specimens will not rapidly crack after the initial cracking in the cyclic loading process, mainly because the fibers are still tensile and can continue to withstand cyclic loading. Microscopic analysis of the fiber-matrix interface reveals that the fibers are well bonded to the matrix and can dissipate energy as a whole, which is the main reason for the high fatigue performance of ECC.