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2024 CSAA/IET International Conference on Aircraft Utility Systems, AUS 2024

作者： Ding, Qianlong Jian, Xizhong Shen, Haiming Zhu, Guangya Zhang, Dalin Chen, Weijian Key Laboratory of Aircraft Environment Control and Life Support MIIT Nanjing University of Aeronautics and Astronautics Nanjing China Shanghai Aircraft Design and Research Institute of COMAC Shanghai China College of Flight Technology Civil Aviation University of China Tianjin China

Concentration distribution of air pollutants in commercial aircraft cabins are important for providing passengers and crew with a healthy and comfortable environment. To verify whether the concentration of air pollutants meets airworthiness standards, this article focuses on the cabin of a specific aircraft and employs numerical simulation to analyze the CO2 concentration distribution during single-engine drift. The MCT single-engine drift calculations reveal that pollutants initially increase and then decrease as the aircraft descends from 7620m to the emergency ventilation altitude, the concentrations of pollutants in the x section, y section and z section increasing by 66.87%, 55.61%, and 61.08% respectively, maintaining pollutant concentrations within acceptable limits throughout the drift. © The Institution of Engineering & technology 2024.

关键词： Aircraft

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Supermaneuverable Flipping Control and Planning Based on Multi-Rotor Mode of Tilt-Rotor UAVs

Supermaneuverable Flipping Control and Planning Based on Mul...

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2024 IEEE International Conference on Robotics and Biomimetics, ROBIO 2024

作者： Wang, Hongpeng Zhang, Qinghao Fei, Yue Deng, Kun Liang, Jun Sun, Chuanyu Xu, Li Civil Aviation University of China The Key Laboratory of Civil Aviation Smart Airport Theory and System China College of Artificial Intelligence Nankai University Tianjin300071 China National University of Defense Technology Laboratory of Science and Technology on Integrated Logistics Support Changsha410073 China Institute of Intelligence Technology and Robotic Systems Shenzhen Research Institute Nankai University Shenzhen518083 China China Nuclear Power Technology Research Institute Co. Ltd Shenzhen518000 China

ISBN: (纸本)9781665481090

Maneuverability is a critical factor for UAV s to survive in high-intensity combat scenarios. Traditional UAV s typically operate in a stable motion state to ensure flight safety. However, in highly contested environments, special missions require high mobility while maintaining safety. Tilt-rotor UAV s, which combine the characteristics of fixed-wing and multi-rotor UAVs, can perform extreme maneuvers, such as high angles of attack and post-stall maneuvers, to rapidly change posture and complete tasks like positioning and defense. Therefore, integrating and optimizing safety and maneuverability metrics is necessary for enabling UAV s to achieve extreme maneuverability. In this paper, extreme maneuver planning and control for tilt-rotor UAV s are realized through a method based on third-order Bezier curve planning of body angular velocity. Experimental results demonstrate tilt-rotor UAVs can perform extreme super-maneuverable flips while maintaining overall process control. © 2024 IEEE.

关键词： Maneuverability

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Numerical simulation on flow boiling characteristics in sinusoidal channels of airborne micro heat exchanger

Numerical simulation on flow boiling characteristics in sinu...

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2021 International Conference on Mechatronics technology and Aerospace Engineering, ICMTAE 2021

作者： Liang, Xingzhuang Xu, Yu Wang, Jian State Key Laboratory of Fire Science University of Science and Technology of China Hefei230026 China AVIC Shenyang Aircraft Design and Research Institute Shenyang110035 China Key Laboratory of Aircraft Environment Control and Life Support MIIT Nanjing University of Aeronautics and Astronautics Nanjing210016 China

With the miniaturization of airborne system, heat dissipation has become a critical issue. Since sinusoidal channel can enhance flow disturbance, it has a stronger heat exchange capacity than that of straight channel. However, flow boiling characteristics in sinusoidal channel are more complex. Here, numerical simulations of flow boiling in sinusoidal and straight microchannels are conducted based on the VOF model with the inner diameter of 1 mm, mass flux of 500 kg/m2 s and heat flux of 50 kW/m2. The effects of channel structure and hypergravity are obtained. The simulation results indicate that bubble evolution in sinusoidal channel is more complex than that in straight channel, and bubbles are more likely to coalesce, deform and break. Vortices appear in sinusoidal channel and disrupt the near-wall boundary layer. Bubble evolution combined with vortices affect the flow boiling performances. For straight channel, dryout is less likely to occur, while for sinusoidal channel, it is more likely due to more drastic flow changes. Furthermore, the transition of flow patterns is faster under hypergravity. For sinusoidal channel, flow patterns transform earlier into slug and circular flows. © Published under licence by IOP Publishing Ltd.

关键词： Vortex flow

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Multivariate Empirical Wavelet Transform and Its Application to Rolling Bearings

Multivariate Empirical Wavelet Transform and Its Application...

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TEPEN International Workshop on Fault Diagnostics and Prognostics, TEPEN-IWFDP 2024

作者： Wang, Zhi Jin, Yitao Zhang, Songtao Cao, Shijun Liao, Yun BeiJing TangZhi Technology Development Co. LTD Beijing100043 China TangZhi Technology Hunan Development Co. LTD Changsha410083 China College of Intelligence Science and Technology National University of Defense Technology Changsha410073 China Laboratory of Science and Technology On Integrated Logistics Support NUDT Changsha410073 China AECC Hunan Aviation Power Plant Research Institute Zhuzhou412002 China AECC Key Laboratory of Aero-Engine Vibration Technology Zhuzhou412002 China

ISBN: (纸本)9783031694820

Empirical wavelet transform (EWT) is a recently proposed algorithm for single-channel signal separation, which has been widely applied in the field of fault diagnosis. With the development of sensors, multi-sensors are increasingly applied in equipment condition monitoring, and multi-channel signals can more comprehensively characterize the fault signals of bearings. Aiming at the problem that EWT cannot deal with multi-channel signals, the multivariate empirical wavelet transform (MEWT) method is proposed in this paper. Through analyzing the simulated fault signals for bearing, the effectiveness of the proposed MEWT method is verified, and the fault types of the bearings can be accurately diagnosed. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

关键词： Roller bearings

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Electrochemical Characteristics and Corrosion Resistance of Alznpbsn High Entropy Alloy in Nacl Solution

SSRN

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SSRN 2024年

作者： Yao, Xiaofei Wang, Weihua Qi, Xiaoling Ma, Yufei Yang, Wei Lv, Yunkun Liu, Yongqin Chen, Jian School of Materials Science and Chemical Engineering Xi’an Technological University Shaanxi Xi’an710021 China Aviation Key Laboratory of Science and Technology on Life-support Technology Hubei Xiangyang441003 China

An innovative corrosion resistance AlZnPbSn high-entropy alloy was prepared that microstructure was characterized, the corrosion resistance was tested. The microstructure of AlZnPbSn alloy is dendritic, eutectic and peritectic, and the composition phase of AlZnPbSn alloy is FCC solid solutions. The corrosion form of AlZnPbSn high-entropy alloy in NaCl solutions of different concentrations is general corrosion, and the corrosion surface is loose and undense. The corrosion products attached to the corrosion surface of alloys are mainly composed of Al and Zn oxides. Sn and Pb are corroded to form Sn and Pb oxides, which dissolve or fall off to form micro-holes or pores on the corrosion surface of AlZnPbSn high-entropy alloy. With increase of NaCl solution concentration, the degree of corrosion products fall off or dissolve increase, so the corrosion rate of AlZnPbSn high-entropy alloy increase. In 10.5% and 14%NaCl solutions, the amount of Al oxides in the corrosion products increase, a locally dense corrosion product was formed on the corrosion surface of AlZnPbSn high-entropy alloy, but which cracked and could not protect the matrix. Therefore, the locally dense corrosion products on the corrosion surface of AlZnPbSn high-entropy alloy in NaCl solutions could not improve the corrosion resistance. © 2024, The Authors. All rights reserved.

关键词： High-entropy alloys

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Effects of Heat Treatment Cooling Methods on Precipitated Phase and Mechanical Properties of Cocrfemnni-Mo5c0.5 High Entropy Alloy

SSRN

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SSRN 2023年

作者： Yao, Xiaofei Wang, Weihua Qi, Xiaoling Lv, Yukun Yang, Wei Li, Tianye Chen, Jian School of Materials Science and Chemical Engineering Xi’an Technological University Shaanxi Xi’an710021 China Aviation Key Laboratory of Science and Technology on Life-support Technology Hubei Xiangyang441003 China

CoCrFeMnNi-Mo5C0.5 high entropy alloys were prepared by vacuum arc melting, and then which heat treatment were carried out by water cooling, air cooling and furnace cooling respectively. the microstructure and phase composition of as-cast and heat treated CoCrFeMnNi-Mo5C0.5 high entropy alloys were examined by SEM, EDS and XRD, the mechanical properties of as-cast and heat treated CoCrFeMnNi-Mo5C0.5 high entropy alloys were tested by the tensile test and hardness test, and the effects of heat treatment cooling methods on precipitated phase and mechanical properties of CoCrFeMnNi-Mo5C0.5 high entropy alloys were investigated. The results show that precipitated phase in CoCrFeMnNi-Mo5C0.5 high entropy alloys is MC phase, which are riches in Mo, Cr and C. With change of heat treatment cooling methods from furnace cooling, air cooling to water cooling respectively, the heat treatment cooling rate is increased, the amount and size of precipitated phase are all decreases, and the position of precipitated phase change from grain boundary to intragranular. The tensile strength and elongation of heat treatment water cooled CoCrFeMnNi-Mo5C0.5 high entropy alloys are 739MPa and 41% respectively, which are realizes the simultaneous increase of strength and plasticity. With increase of heat treatment cooling rate, the hardness of CoCrFeMnNi-Mo5C0.5 high entropy alloys decrease, the elongation increase, the plastic deformation occurs mainly in the uniform plastic deformation stage. The fracture mode of as-cast CoCrFeMnNi-Mo5C0.5 high entropy alloy is intergranular fracture, the fracture mode of heat treatment furnace cooled, air cooled and water cooled CoCrFeMnNi-Mo5C0.5 high entropy alloys are all transgranular fracture. © 2023, The Authors. All rights reserved.

关键词： Iron alloys

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Initial Phase Determination Method for Vibration Separation technology of Planetary Gear Train 1

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TEPEN International Workshop on Fault Diagnostics and Prognostics, TEPEN-IWFDP 2024

作者： Jin, Yitao Wang, Zhi Xu, Fujian Zhang, Hongtai Liao, Yun BeiJing TangZhi Technology Development Co. LTD Beijing100043 China TangZhi Technology Hunan Development Co. LTD Changsha410083 China College of Intelligence Science and Technology National University of Defense Technology Changsha410073 China Laboratory of Science and Technology on Integrated Logistics Support NUDT Changsha410073 China AECC Hunan Aviation Power Plant Research Institute Zhuzhou412002 China AECC Key Laboratory of Aero-Engine Vibration Technology Zhuzhou412002 China

ISBN: (数字)9783031694837

ISBN: (纸本)9783031694820

Planetary gear box has excellent heavy load capacity due to its unique design, and is used in a variety of occasions, including wind turbine gearbox, helicopter transmission main reducer, etc. The Vibration Separation (VS) technique is based on the time-synchronous averaging technique. The meshing vibration data block with the shortest transmission path between the meshing position and the sensor is picked up, and then the vibration signal of the moving part is mapped and reconstructed through the index table. The planetary gear follows the movement of the planetary frame, and the meshing position is affected by the rotation of the planetary frame. Based on this situation, the vibration data caused by the rotation of the planetary frame is obtained by narrow-band filtering, and then the initial phase is obtained by calculating the vibration energy. Finally, the feasibility of the technique is verified by the fault implantation test. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

关键词： Wind turbines

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Optimal design of water immersion sensor layout for helicopter emergency flotation system based on the nsgaII algorithm 2

Optimal design of water immersion sensor layout for helicopt...

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2023 2nd International Conference on Aerospace and Control Engineering, ICoACE 2023

作者： Wang, Bingqian Wang, Zhe Sun, Zhi Hou, Bin College of Civil Aviation Nanjing University of Aeronautics and Astronautics Nanjing211106 China Key Laboratory of Aircraft Environment Control and Life Support MIIT Nanjing University of Aeronautics and Astronautics Nanjing210016 China Key Laboratory of Civil Aviation Emergency Science and Technology CAAC Nanjing University of Aeronautics and Astronautics Nanjing211106 China Environment Control System Research Department COMAC Shanghai Aircraft Design & Research Institute Shanghai201210 China

Aiming at the problem of sensor layout in an emergency flotation system, a sensor layout scheme design method based on the NSGAII method is proposed. The ALE method is used to simulate the water landing process of the helicopter on different pitch angles. The logic relationship of the 4/5 voting system is used to improve the sensor module reliability. Further, a mathematical model of layout scheme is established to maximize the detection coverage and minimize the force acting on the water immersion sensors when helicopter emergent water landing as the objective functions. Based on the mathematical model of water immersion sensor layout optimization constructed in this paper, NSGAII is used to solve this problem. The results show that the proposed method can realize the optimization of the layout of the water immersion sensor, the detection coverage of optimized schemes is increased by 3.26% on average compared with the value under the original scheme, and the force acting on the water immersion sensors is reduced by 61.86%. © Published under licence by IOP Publishing Ltd.

关键词： Flotation

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Numerical simulation of impact of ejection seat rocket motor ignition shock waves on aircraft windshield loading

Numerical simulation of impact of ejection seat rocket motor...

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CSAA/IET International Conference on Aircraft Utility Systems (AUS 2024)

作者： Liang Wu Lou Jin Hang Xu Yibin Wu Overall Technology R&D Department AVIC Aerospace Life-support Industries Ltd. Xianyang 441000 People's Republic of China Aviation Key Laboratory of Science and Technology on Life-support Technology Xianyang 441000 People's Republic of China

ISBN: (数字)9781837242108

Aircraft windshield fragmentation during seat ejection can adversely affect crew ejection from the aircraft safety. In this paper, the shock wave loads caused by the firing of an ejection seat rocket motor were simulated numerically, and the numerical simulation flow was designed with the dynamic grid technique. The results show that the pressure peak of the inner surface monitoring point at the front end of the windshield is 9.4% lower compared with the test value at the same location when the rocket engine is firing at 0 km/h velocity ejection, which proves the numerical simulation method feasible. The effects of rocket pack ignition shock waves on the aircraft windshield can be divided into shock wave loading phase and quasistatic pressure loading phase. The former has a large peak load and a short duration, while the latter has a small peak load and a long *** corners within the cockpit, converging phenomena occur during shock wave propagation, and the area near the cabin inner wall at the front and sides of the aircraft's windshield is more heavily loaded and has a higher risk of damage than other areas. The moment of maximum windshield loading for each calculated state is the moment of the first load peak. Due to the high velocity airflow blowing effect, the maximum windshield loading at 1100 km/h ejects is close to the zero velocity ejection value, acting in the opposite direction. The zero velocity ejection and impact loads at 1100 km/h eject should be emphasized in the windshield strength analysis.

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Augmented Reality-Based Digital-Physical Space Registration and Projection for Cognitive Enhancement and Assessment

Augmented Reality-Based Digital-Physical Space Registration ...

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2024 IEEE International Conference on Robotics and Biomimetics, ROBIO 2024

作者： Wang, Hongpeng Fei, Yue Zhang, Qinghao Deng, Kun Liang, Jun Sun, Chuanyu Xu, Li Civil Aviation University of China The Key Laboratory of Civil Aviation Smart Airport Theory and System China College of Artificial Intelligence Nankai University Tianjin300071 China National University of Defense Technology Laboratory of Science and Technology on Integrated Logistics Support Changsha410073 China Institute of Intelligence Technology and Robotic Systems Shenzhen Research Institute of Nankai University Shenzhen518083 China China Nuclear Power Technology Research Institute Co. Ltd. Shenzhen518000 China

ISBN: (纸本)9781665481090

Driven by information technology, mod-ern warfare is more diverse and intelligent than traditional warfare, in which intelligent unmanned system plays an increasingly important role. To defend against distant threat of unmanned military arma-ments, it's essential to deploy radars, sonars, satellites, and other long-range detection equipment to build a multidimensional national defense monitoring system. Due to the unpredictable nature of battlefield, radar-based reconnaissance missions require operators to have extensive experience and maintain a high level of focus. However, prolonged radar operations may impose a heavy psychological burden on operators and even affect their mental functions. To address these challenges, this paper proposes a cognitive en-hancement and assessment system that projects virtual 3D battlefield scenarios onto the real world based on augmented reality and evaluates operators' mental state through eye-tracking technology. © 2024 IEEE.

关键词： Augmented reality

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