bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal breakdown characteristics and damage mechanisms of novel GaN HEMT aviation nanodevices in high-intensity radiation fields
Authors: Ma Zhenyang , Liu Dexu , Xu Ke , Duan Zhaobin 
Published: August 2024

Abstract
This paper designs a novel GaN HEMT aviation nanodevice through the Sentaurus-TCAD simulation software. The thermal breakdown characteristics of the device in a high-intensity radiation field environment are investigated. The impact of parameters in the channel and barrier layer on the breakdown of the device is analyzed. The electromagnetic environmental effects of the device are verified, and the damage law of the device is obtained. By injecting high-power microwave signals into the gate, the strength of the internal electric field, concentration of the current, and peak temperature of the device are analyzed to assess their impact on device damage. Research has shown that the doping concentration, structural size, and aluminum doping ratio of the barrier layer significantly affect the distribution of internal field strength and carrier concentration within the device, thereby influencing its breakdown characteristics. The concentrations of Al and impurity doping in the barrier layer affect the device’s breakdown characteristics. Consequently, this novel GaN HEMT aviation nanodevice exhibits a higher breakdown voltage and stability, making it more suitable for application in high-frequency harsh environments.
Numerical simulations of water spraying on the deflector during rocket offshore launching
Authors: Su Yifei , Cui Yangwen , Le Guigao 
Published: August 2024

Abstract
Cooling effect of the water jet on the face of the deflector during offshore launching process of the vehicle is studied in this paper. Based on the Reynolds averaging method and three-dimensional Navier-Stokes equations, a realizable k-ε turbulence model simulates the high-speed gas flow in a rocket engine, and the Euler discrete method simulates the gas-liquid coupling between water and engine gas. The accuracy of the above numerical method is verified by comparing the flow field simulation results with the water spray experiment results. Research has shown that during the launch process of the launch vehicle, the surface thermal environment of the 0-meter-high deflector is the most severe. After cooling by spraying water, the cooling of the jet core area on the surface of the deflector is not obvious, but the temperature of other areas decreases significantly. The pressure on the surface of the deflector will not change significantly. Results provide effective solutions for improving thermal environment of the deflector surface during rocket offshore launching and reducing the deflector surface erosion.
Research on throat type variable thrust solid rocket motor
Authors: Yin Yongqi , Hu Zongchun , Zhu Xiaoguang , Wu Yake , Chang Zhiqiang , Xu Xuezheng , Shu Hongbin , Zhu Chengyong 
Published: August 2024

Abstract
Solid Rocket Motors (SRM) is a power propulsion device using solid propellant, which has obvious advantages in structure, reliability, and ease of use compared with other types of power propulsion devices. With the continuous development of science and technology, the real environment puts forward higher requirements for the maneuverability of rocket engines, and engines with fast start ability and power adjustment functions are becoming more and more important. Therefore, variable thrust solid rocket engines occupy a very important place in the development of future rocket engines. In this paper, the working principle of the throat plug engine is analyzed, and the functional relationship between the thrust and the displacement of the throat plug is derived. The throat bolt solid rocket motor changes the minimum cross-sectional area of the nozzle through the reciprocating motion of the throat bolt on the central axis and then changes the thrust. By establishing a Cartesian coordinate system to describe the shape of the throat plug and the nozzle in the shape of a functional curve, the problem of the minimum cross-sectional area of the nozzle of any throat plug configuration is transformed into the problem of the shortest distance between the two curves, and the established functional relationship between the thrust force and the displacement of the throat plug provides a basis for the design of the throat plug configuration.
Analysis and study on the minimum allowable clearance between civil aircraft fan cowling and flaps
Authors: Feng Kai , Pan Lijun , Jin Ding , Li Chen 
Published: August 2024

Abstract
In the development of civil aircraft, the evaluation of the minimum allowable clearance between the fan cowl opening and flaps is a crucial factor in determining the maintainability of civil aircraft and an essential aspect of the development process for civil aircraft models. To ensure that the aircraft does not experience poor maintainability or interference issues during ground maintenance due to insufficient clearance, this paper proposes a clearance analysis method to study the minimum allowable clearance between the fan cowl opening and flaps during maintenance. The paper outlines the approach to clearance analysis, explains the principles of clearance control, and discusses factors influencing clearance. Finally, using a specific aircraft as a case study, the paper provides a detailed description of the factors to be considered in calculating and analyzing the minimum allowable clearance between the fan cowl opening and flaps. The research results also demonstrate the practical engineering value of this clearance analysis method.
Civil aircraft negative acceleration airworthiness regulation differences analysis and certification
Authors: Zhang Ruihua , Zhou Liang 
Published: August 2024

Abstract
This article starts by analyzing the negative acceleration clause in the civil airworthiness regulations of the United States, Europe, and China, and it also conducts comparative analysis and research on airworthiness verification methods and flight test indicators for civil aircraft with negative acceleration scenarios. Moreover, suggestions are given for airworthiness verification objects and methods. This article has a reference value for the analysis of negative acceleration scenarios in civil aircraft design and guides the design of negative acceleration airworthiness verification flight subjects.
Numerical simulation of reverse jet flow of transonic slender body
Authors: Li Kangkang , Liu Yuwei , Liu Yaofeng 
Published: August 2024

Abstract
The modern vehicle usually uses a gas rudder in the active phase or a pulse engine in the passive phase to realize rapid maneuvering. Under the circumstances of a large angle of attack (short by AOA), nozzle jet flows of the main engine are contrary to the free stream, which leads to complex jet interference on the surface of the body. This paper carries out a numerical simulation of jet interference in the reverse direction of the main engine jet under the condition of transonic velocity for typical shapes and obtains the flow field characteristics of the reverse flow under both the long penetration model and short penetration model. The jet interference characteristics are also studied. Finally, the interference of the reverse jet on the tail rudder is studied, and the rule of rudder effect under different penetration modes is obtained. In short penetration mode, the rudder effect is the opposite and much bigger than that without the main engine jet flow.
The extraction method of the time difference in the output angle of MLS
Authors: Sun Shixiang , Jin Shan , Wang Xiaoxu 
Published: August 2024

Abstract
The extraction and calculation method of the output angle signal of the Microwave Landing Simulator (MLS) is crucial for simulating the landing process of the aircraft. This study aims to explore the extraction and solution methods for the angle signals output of microwave landing simulators. Firstly, the microwave signal is collected and processed by the simulator to obtain raw data related to the relative position and angle between the aircraft and landing equipment output. Next, signal processing techniques, waveform analysis, and mathematical calculations are used to process and resolve the original data. For the output angle signal, emphasis is placed on the extraction of the forward scanning beam, backward scanning beam, and pulse 3dB points. Finally, the effectiveness and reliability of the proposed method in microwave landing simulators are evaluated through practical application verification. The results of this study provide new methods and technical support for the extraction and calculation of angle signals in microwave landing simulators, which is of great significance for the simulation and optimization of aircraft landing processes.
Research on the influence of ducted fan position on the performance of powered high-lift system
Authors: Li Gang , Song Hui , Mao Sen 
Published: August 2024

Abstract
The ducted fan-powered high-lift system realizes the lift increase effect in the form of blowing flaps. The position of a ducted fan is the most critical parameter in the design of a ducted fan-powered high-lift system. An analysis model of ducted fan blowout flap of a vertical/short take-off and landing (V/STOL) Unmanned Aerial Vehicle (UAV) with three ducts is established in this paper. T-Rex unstructured grid technique and Reynolds mean method (RANS) were used for simulation calculation. The influence of the position of the ducted fan on the performance of the ducted fan high-lift system is studied on this basis. The results show that the horizontal forward movement of the ducted fan can increase the lift coefficient and lift drag ratio. When the ducted fan moves up, the lift-drag ratio increases, but the lift coefficient decreases. In the vertical direction, the proper position is chosen by the wing as far as possible. The negative installation angle of the ducted fan will obtain a larger lift coefficient. Changing the position of the ducted fan for greater lift usually also results in greater bow torque, which puts a greater burden on the tail trim.
Numerical simulation of unsteady characteristics of large flow rate jet interference
Authors: Liu Yuwei , Li Kangkang , Wang Xincheng , Liu Yaofeng 
Published: August 2024

Abstract
In this paper, for a cone-column-skirt spiral shape, the unsteady characteristics of complex flow caused by strong interference of large flow jets and high-speed incoming flow are studied. The unsteady numerical simulation method based on partition docking structure grid and double time step iteration is used to implement the integrated unsteady calculation of external flow around the aircraft/nozzle flow. The unsteady characteristics of large flow jet interference under the influence of jet startup and shutdown, different jet pressure building forms, and incoming flow conditions (flight altitude, flight Mach number, and angle of attack) are studied. The characteristics of the jet interference flow field structure, jet thrust coefficient, and aerodynamic interference coefficients of the projectile body over time under various conditions are discussed. The research results can provide necessary references for relevant aircraft design.
Fault diagnosis of flight control system based on BWO-VMD-DNCNN
Authors: Gui Huazhan , Zhao Yifei , Zhang Ying , Yuan Quan , Li Kai , Li Zhaorui , Yuan Feng 
Published: August 2024

Abstract
The flight control system of commercial aircraft is the core system of the aircraft and is directly related to whether the aircraft can fly safely. There are difficulties in fault diagnosis of flight control systems, such as noise and complex signals in the collected signals. This paper proposes a fault diagnosis method to solve this problem, using the Beluga Whale Optimization (BWO) and the denoise convolutional neural network (DNCNN) improved variational mode decomposition combined with the support vector machine optimized convolutional neural network. Firstly, the signal undergoes decomposition using variational mode decomposition, followed by the introduction of Beluga Whale Optimization. The minimum envelope entropy serves as the fitness function, and the determination of the number of decomposition layers and quadratic level of variational mode decomposition relies on the fitness value, incorporating a penalty factor. Secondly, enhancements are made to the denoising convolutional neural network to adapt it for one-dimensional signal denoising. The denoising convolutional neural network is used to denoise each mode after variational mode decomposition, and the denoised modes are reconstructed to obtain the denoised signal. Finally, the convolutional neural network (CNN) is used to extract data features, and the support vector machine (SVM) is used to replace the Softmax classifier in the convolutional neural network to realize fault diagnosis of the flight control system. According to the results of the experiment, the method is universally applicable, demonstrating strong diagnostic ability and high diagnostic accuracy.
Numerical research on rain field intensity and uniformity of a high-velocity rain wind tunnel
Authors: Liu Qianqian , Liu Huayuan , Zhou Qiongyao , Dong Mingsai 
Published: August 2024

Abstract
Rain field intensity and uniformity are essential to high-velocity rain wind tunnels. This paper investigated the rain field of a high-velocity rain wind tunnel via a two-way coupled Eulerian-Lagrangian approach. The simulation results show that the spray diffusion degree is mainly affected by air velocity, followed by the initial particle velocity. The intensity of the rain field increases with the growth of the nozzle flow rate and the increase of the air velocity, while the uniformity of the rain field is mainly affected by the air velocity. Under the same air velocity and nozzle flow rate, the farther away from the outlet, the lower the rain field intensity, while the uniformity of the rain field displays the tendency to rise initially and then decline.
Follower’s guide rail slope angle parameterization research for special high-speed cylinder cam mechanism
Authors: Liu Chang , Yang Zhen , Xu Jian , Ai Zhiyuan , Wang Guoqiang 
Published: August 2024

Abstract
In order to research the relationship between the follower’s guide rail’s slope angle and the drive pressure force on the main roller and improve the driving condition, the main roller, and the follower system’s dynamics analysis is done. It expresses the rotating motion of the main roller and the longitudinal movement of the follower, respectively, using the momentum moment theory and Newton’s Second Law. The cycle program is created by using the method of parameterizing the slope angle between the guide rail and the horizon direction while maintaining the follower’s transverse direction width. The results of the calculation show that: the drive pressure force grows monotonically and has an approximate linear connection with the guide rail’s slope angle; the guide rail’s slope angle has no effect on the time at which the main roller’s pressure force peaks. The curve between driving pressure force and slope angle has a larger slope rate when the rotating body has a higher rotary velocity. The horizon guide rail will be therefore given precedence in the follower design process for the high rotational velocity cam mechanism, starting from the point of drive pressure force. However, the best combination for self-aligning after wear is a guide rail with a short slope angle and a cam curve with a small acceleration.
Civil aircraft air conditioning and refrigeration control system hil simulation design based on NI VeriStand
Authors: Zhang XueLing , Duan Chun , Wang Yuzhi , Lu Ding 
Published: August 2024

Abstract
This article introduces the hardware-in-the-loop (HIL) simulation design of a civilian aircraft air conditioning refrigeration control system based on NI VeriStand. It elaborates on key technologies such as model-based control algorithm development and embedded code generation in the design process. Additionally, it conducts temperature control experiments at system outlets under different operating conditions on the hardware-in-the-loop platform and compares the results with Simulink simulation, verifying the correctness of the generated code and the feasibility of the platform system solution. This work also lays the foundation for rapid design and optimization of control systems in the future.
Control technology of airborne photoelectric tracking system
Authors: Zhou Fangyan , Wang Hu , Niu Shuaixu , Liu Xiaoqiang , Ren Zelin 
Published: August 2024

Abstract
In order to achieve effective control of the airborne photoelectric tracking system and optimize the system control performance, accelerometers are introduced on the basis of the traditional gyroscope-based dual-loop control to optimize the performance of the control system. However, accelerometer signals are subject to errors due to both drift and noise in the lower frequency bands, which affects the effectiveness of the control system. In order to address this issue, an acceleration signal fusion method is proposed to obtain more accurate acceleration signals using velocity difference to fuse with accelerometer signals. The fused acceleration signals are used to implement acceleration feed-forward control to optimize control performance.
Developing active-spoiler on a new BEV using combined methods
Authors: He Yue , Yi Heng 
Published: August 2024

Abstract
This paper presents a new type of active aerodynamic device that can decrease overall aero drag by improving base pressure recovery. The ideology of using an active spoiler is, in fact, a compromise between aerodynamic performance, styling, and technical propaganda requirements. The proposal of implanting an active spoiler first came to us by observation from some luxurious cars on the road: Panamera, 911, Audi A7, etc. However, it is very difficult for us to find certain SAE papers that can exclusively depict the mechanism behind those active spoilers that are equipped on family vehicles. Therefore, it is our mission to explore it with our own CFD simulations and wind tunnel tests. In this paper, a full model of a new rear-design electronic vehicle was built along with several spoiler designs. Multiple rounds of CFD simulations were run to verify the effect of active spoilers from different positions. By carefully investigating the flow field around the active spoiler and vehicle rear, the Cd fluctuation amongst varieties of spoiler angle and elevation was obtained to facilitate final decision-making in terms of the active spoiler. Finally, a discussion and analysis of the disparity between test results and the numerical ones has been conducted, followed by the final conclusion.
The influence of harness parasitic parameters of arc power supply controllers
Authors: Peng Zheng , Li Zongliang , Li Ze , Li Zhong , Song Fei , Liu Yizhuo , Zhang Lin 
Published: August 2024

Abstract
In the arc propulsion system, the arc thruster (AT) generates a large, fast transient current at the moment of arc initiation. The parasitic parameters of the harness connecting the AT and the arc thruster power control unit (ATPU) induce a high-voltage electromotive force under the fast transient current condition. If the high-voltage electromotive force exceeds the rated voltage of the ATPU device, it will affect the reliability of the ATPU. This article proposes measures to reduce the impact of harness parameters on ATPU based on AT arc characteristics and harness parasitic parameters in order to improve ATPU reliability.
Experimental and numerical investigation on wheel regional aerodynamics in an electric vehicle
Authors: Yi Heng , Zeng Yi , Wan Liming , Huang Shunqiao , Sun Richard , Huang Tao , Hu Yuanzhi , Ma Fayue 
Published: August 2024

Abstract
The aerodynamic development of electric vehicles (EVs) has drawn more and more attention recently due to its direct relationship with EVs’ power consumption and driving range. The wheel regional aerodynamics are complex and important, rendering them a hot research topic. In this work, wind tunnel tests and CFD simulations are performed to investigate the regional aerodynamics of wheels in an electric SUV, taking into account the interference effects between the tires, automatic grille shutter (AGS), and front wheel deflectors. Since the vehicle’s aerodynamic drag coefficient is the focus of this research, three parameters with major effects on the drag coefficient, including tire width, AGS status (open/closed) and height of front wheel deflectors, are chosen for a parametric study in a wind tunnel. The wind tunnel results show that the experimental drag coefficient increases linearly with the increase in tire width. Linear regressions show that the sensitivity coefficients, affected by the status of the AGS and height of the front wheel deflectors, range from 5.0 to 7.6 counts for a 10 mm increase in tire width. The drag coefficient is reduced by reducing the height of the front wheel deflectors from 50 to 30 mm in all cases investigated, and the reductions range from 0.8 to 7.6 counts. Reductions of the drag coefficient by closing the AGS range from 13.2 to 19.1 counts and a cooperative drag reduction effect is observed between closing the AGS and reducing the height of the front wheel deflectors. CFD simulations are performed to visualize the flow patterns, and the flow field information extracted is used to explain some of the experimental phenomena. This work proves that both wind tunnel tests and CFD simulations are useful tools for investigating wheel regional aerodynamics in electric vehicles.
Effect of the repetition frequency and polarity of square wave voltage on the partial discharge of electric machine insulation for more electrical aircraft
Authors: Wang Jianwen , Kong Yongjin , Cai Yi , Wang Yalin 
Published: August 2024

Abstract
More electric aircraft (MEA) are featured with the electric propulsion system, which is more efficient and environmentally friendly than traditional aircraft. Partial discharge (PD) caused by high-frequency square wave electrical stress and environmental stress is the main reason for the failure of electric machine insulation for MEA. To study the effect of the repetition frequency and polarity of square wave voltage on partial discharge characteristics, a partial discharge detection platform is set up, using an ultra-high-frequency (UHF) down-mixing method and optical method to detect PD. These two methods are proven to be effective in measuring the PD impulse signal under square wave voltages. Meanwhile, considering the actual operating condition of MEA, the high voltage square wave is applied on samples of twisted pairs under different air pressures (down to 20 kPa) and different repetition frequencies (up to 5 kHz). The results show that the increase in the frequency of the square wave and the decrease in air pressure lead to a lower PDIV. In addition, electric field distribution under square wave voltage of different polarities and frequencies and the dielectric relaxation process of gas-solid composite insulation for electric machine insulation are analyzed to explain the results physically.