bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of different particle sizes on combustion characteristics of DCR engines
Authors: Zhao Dongsheng , Wei Zhijun , He Duanyang , Dalin Li , Chujiu Huang 
Published: May 2024

Abstract
The ramjet engine has undergone rapid development in recent decades, and the dual combustion chamber ramjet (DCR) engine was proposed in the last century. Boron, with its high volumetric and gravimetric heating values, is one of the most attractive fuel additives for ramjet engines. However, due to the problem of low combustion efficiency, boron is difficult to achieve high efficiency combustion in practical applications. In order to investigate the combustion characteristics of boron-containing gas solid phase components in DCR engines, the Realizable k-ε model, finite rate/vortex dissipation model and boron particle King model ignition combustion calculation program were written. A three-dimensional full-scale two-phase flow numerical simulation was carried out in the combustion chamber of the DCR engine to calculate the effects of different particle sizes on the combustion characteristics. Through the analysis of the simulation results, the particle size affects the ignition time of boron particles and is positively correlated with the combustion efficiency, but with a non-linear growth. A smaller particle size can promote the ignition of boron particles, improve the solid phase combustion efficiency and achieve efficient combustion.
Design of ignition control system for failed spacecraft array solid thruster
Authors: Liao Tenghui , Deng Hanyu , Tang Yuqing , Pu Yantao , Cao Ping 
Published: May 2024

Abstract
The life of micro-nano spacecraft is generally short. In order to solve the problem of space debris endangering space safety after its failure and make it deorbit quickly, this paper has carried out the hardware system design and software system design of the ignition control system of the failed spacecraft attitude adjustment solid thruster. In order to facilitate the realization of high integration, the hardware system adopts the array arrangement circuit and selects the MOSFET as the driving switch. The software system receives the ignition command from the spacecraft platform and enables the row and column control terminals of the ignition circuit to achieve addressing ignition. The results show that the control module can correctly receive the instructions from the spacecraft platform and make the correct ignition action, successfully complete the attitude adjustment task, and improve the reliability of the deorbiting of the failed spacecraft.
EHFE refinement and extension for variable physical Earth radiation in spacecraft uncertainty thermal analysis
Authors: Fu X , Liang L , Ma W , Cui H , Zhao Y 
Published: May 2024

Abstract
Spacecraft uncertainty thermal analysis is an important part of ensuring robust and reliable spacecraft thermal control system design. The calculation of the Earth external heat flux is an important part of it, however, the current model for calculating the Earth external heat flux is the constant physical Earth radiation model. In this paper, a model of the Earth’s variable physical radiation is developed based on the long-term averaging method. We refine and extend the application of the external heat flux expansion (EHFE) formula to accommodate our proposed model. This study further includes an uncertainty analysis of Earth radiative external heat flux, utilizing the enhanced EHFE formula in the context of a representative spacecraft. We provide statistical data, such as mean values, standard deviation, and probability density functions, derived from our analysis. The augmented EHFE formula, when properly generalized, can be applied to compute the celestial body’s variable physical radiative external heat flux affecting the spacecraft. This methodological advancement offers theoretical underpinning for the thermal design of spacecraft intended for deep space exploration.
Numerical simulation of deformation hysteresis effect of the bristles of brush seals
Authors: Li Pengfei , Hu Yaping , Ji Honghu 
Published: May 2024

Abstract
Because of their good sealing performance, brush seals are used widely in turbomachinery as alternatives to traditional labyrinth seals. However, obstructed by friction, the flexible bristles cannot recover fully after deformation, resulting in a hysteresis effect and decreased sealing performance. In the present study, a three-dimensional multi-row bristle model is established that considers the friction between the neighbouring bristles and back plate. Then the deformation and recovery of the bristles during the radial reciprocating offset of the rotor in the presence of a pressure difference are studied. To evaluate the hysteresis effect, analysis is directed at the unrecovered bristle deformation in the radial direction affected by bristle diameter, bristle lay angle, fence height and width of pressure relief chamber. The results show that the larger the bristle diameter and fence height, the weaker the hysteresis effect and the larger the bristle lay angle, the stronger the hysteresis effect. With increasing width of the pressure relief chamber, the hysteresis effect weakens and then strengthens, meaning that the pressure relief chamber has an optimal axial width that departure from enhances the hysteresis effect. The present results offer a reference for selecting the structural parameters of brush seals in engineering design.
Numerical study on dynamic flow of flexible extension nozzle in rocket motors
Authors: Duanyang He , Zhijun Wei , Xudong Zhang , Dalin Li , Dongsheng Zhao , Chujiu Huang , Haixu Yu 
Published: May 2024

Abstract
The use of extension nozzles in rocket propulsion systems is one of the effective methods to increase the geometric expansion ratio and thrust of the nozzle. As a new type of extension nozzle, the flexible extension nozzle can achieve continuous changes in nozzle expansion ratio. To explore the characteristics of the flow field structure at the “bulge” structure and the step structure in the actual configuration of the flexible extension nozzle, and the impact on the performance of the nozzle, a three-dimensional numerical simulation model of the flexible extension nozzle was first established to study the flow field at the “bulge” structure, and then a two-dimensional unsteady numerical simulation model was established by using the coupling technology of dynamic grid and overlapping grid to study the flow field at the step structure. The results show that during the unfolding of the nozzle surface, a complex flow structure of “expansion fan-mixing layer-shock-vortex” were formed in the step area at the junction of the fixed section and the moving extension section. The specific impulse loss of the 3D model is larger than that of the 2D model due to the consideration of the “bulge” structure. The flow loss of the “bulge” structure and the step structure to the nozzle is 0.73% and 0.65% respectively.
Dynamic modeling of shaping-changing cross parachute
Authors: Wang Chunhui , Zhou Hongmiao , Yu Jianqiao 
Published: May 2024

Abstract
The research explored the dynamic simulation of a cross parachute as an actuator, and proposed a method for dynamic modeling to adjust the configuration of the cross parachute. Initially, based on the method of multi-body dynamics modeling, a coordinate system necessary for system simulation was established. Subsequently, by incorporating the changing configuration parameters as input, a dynamic simulation model of the cross parachute with adjustable configuration was developed. Dynamic simulations were executed for the suggested model under two scenarios: changing configuration and symmetric configuration. The simulation results indicated that the parachute with changing configuration could generate radial forces related to the inflow velocity, with the force significantly increasing as the inflow velocity increased. The modeling approach offers a new perspective for the study of the dynamics of using a cross parachute as a control actuator, while the simulation results provide a degree of reference for research into the control force offered by a variable configuration cross parachute.
Research on dynamic prediction method of temperature environment of unmanned aerial vehicle platform based on physical information and neural network
Authors: Li H , Zhang J J , Fu Y , Xu J , Hao Y J 
Published: May 2024

Abstract
During the flight of an unmanned aerial vehicle, the temperature environment inside the cabin is very harsh, resulting in frequent malfunctions of airborne equipment. Therefore, it is necessary to predict the temperature environment experienced by airborne equipment during its life cycle in the early stages of design to support the formulation of design requirements, determine test verification conditions, used and maintained. In order to accurately predict the temperature environment of the unmanned aerial vehicle platform, this paper proposes a prediction method that integrates physical information and neural networks. In view of the thermal environment characteristics of unmanned aerial vehicle platform, the physical mechanism of the formation and transfer of the unmanned aerial vehicle thermal environment was analyzed. Based on the physical mechanism equations and combined with the measured data of unmanned aerial vehicles, an Elman neural network model was established to achieve high flight speed, speed, etc. parameters are characterized as a function of the temperature inside the unmanned aerial vehicle cabin, and finally the model is verified. The results show that the temperature environment prediction model integrates physical information and neural networks can accurately predict the dynamic changes in the temperature inside the unmanned aircraft cabin. The maximum error of the model is 2.76°C, which meets engineering needs.
Dijkstra algorithm based minimum acceleration/snap quadrotor UAV trajectory planning
Authors: Cai Zizhuo , Selezneva M S , Yang Mo 
Published: May 2024

Abstract
This paper focuses on path planning using the Dijkstra/A* algorithm and addresses the trajectory generation problem using the minimum acceleration/snap approach. Firstly, the mathematical model of the optimization problem is formulated, specifically utilizing the Euler-Lagrange equation to derive the necessary conditions for achieving minimum acceleration/snap trajectories, which are represented by either 3rd or 7th order polynomials. The coefficients of these polynomials are determined by imposing appropriate constraints on velocity, acceleration, and higher-order derivatives. Subsequently, a detailed comparison of the performances of the two optimization methods in complex environments is conducted, evaluating differences in position and velocity. Based on the deterministic analysis, conclusive results are obtained.
Design and research of an electric unmanned aerial vehicle power system
Authors: Zhao Anmin , Wang Tiancheng , Liu Deshan 
Published: May 2024

Abstract
An Electric power test system of UAVs is presented, which can be applied to validate the efficiency of UAV propulsion systems and provide reliable verification for propeller numerical calculations. The design proposal, working principle, test equipment and test experiment is introducted. Reliability of various functions of the system is examined and assessed through the multiple comparisond tests, which indicates that, when subjected to identical conditions, the numerical solutions for propeller thrust, torque, and motor efficiency exhibit average errors of 1.02%, 10%, and 10.04%, respectively. The results indicate that the power system test platform effectively validates numerical calculation results, providing reliable engineering application value for general UAV propulsion system research. The findings of this study offer support for optimizing power systems of the UAV, providing valuable references for future engineering applications and development.
An overview of icing scaling parameters for supercooled large drop icing conditions in icing wind tunnels
Authors: Sun Mingming , Jie Yuwen , Wang Liping , Zhou Feng 
Published: May 2024

Abstract
Aircraft icing is a serious threat to flight safety, especially the abnormal ice accumulation on the wing surface under the icing conditions of supercooled large droplets (SLD). Icing wind tunnel test is one of the main means of conducting research on aircraft icing, and the icing scaling law is the theoretical basis for selecting the similarity of characteristic parameters. In order to deeply understand the problems related to icing similarity in icing wind tunnel test under SLD icing conditions, the test capabilities on SLD icing conditions for the existing ice wind tunnel and the common similar parameter scaling methods were reviewed. The icing similarity transformation of SLD icing test was emphasized and the advantages, disadvantages, and applicability of each icing scaling law were analyzed. It can provide some references for the SLD icing wind tunnel test for large civil aircraft.
Sensitivity analysis of attack helicopter combat indicators based on machine learning
Authors: Sun L , L q l  , Gao F 
Published: May 2024

Abstract
This paper focuses on sensitivity analysis in the design of Attack helicopter combat indicators, and combines the advantages of machine learning to propose a combat effectiveness oriented sensitivity analysis method for Attack helicopter combat indicators. Firstly, the steps of sensitivity analysis of Attack helicopter combat indicators based on machine learning are introduced. Secondly, through operational scenarios, constructing indicator systems, collecting relevant data, evaluating effectiveness, and using machine learning algorithms for modelling and training, the sensitivity assessment of the damage probability of Attack helicopter to ground armoured weapons can be achieved. This paper is able to provide reference for the sensitivity analysis of weapon equipment system effectiveness, and provide more scientific and reasonable support for the research and application of helicopters in combat systems.
Research on icing scaling technology for large civil aircraft icing wind tunnel test
Authors: Liu Jia , Chen Yingchun , Zhou Feng , Zhao Binbin 
Published: May 2024

Abstract
This article explores the icing scaling technology for large civil aircraft icing wind tunnel tests. Based on the typical critical icing conditions of large civil aircraft and the calibration of icing wind tunnel, and through the similarity analysis of water droplet trajectories, water collection, and energy balance, four similar parameters, namely modified inertia parameter, drop energy transfer parameter, stagnation freezing coefficient, and accumulation parameter, were selected as similarity criteria for icing scaling. Based on this criteria, icing scaling was conducted on the critical icing conditions of large civil aircraft, and the scaling results were evaluated by icing code. The results show that the water droplet collection and the ice shape before and after the scaling are in good agreement, and the similarity criteria used are appropriate. Finally, icing wind tunnel test was conducted in 3m × 2m test section using scaled icing conditions. The test results show that the main characteristics of the experimental ice shape are in good agreement with the calculated ice shape, and the calculated ice shape is more critical. The calculated ice shape can be used as a critical ice for aerodynamic wind tunnel tests and flight tests with simulated ice.
Research on ice shedding experiment for large civil aircraft to exit ice protection mode
Authors: Sun Mingming , Jie Yuwen , Zhao Binbin , Zhou Feng 
Published: May 2024

Abstract
While aircraft flying, once the icing detector finds the icing environment, the stall protection system will turn on the icing stall protection mode. After aircraft leaves the icing environment, due to the lack of effective means to determine whether there is still ice on the unprotected surface of the aircraft, it is impossible to exit the icing stall protection mode, which can lead to issues such as high approach speed of the aircraft, affecting landing safety and passenger comfort. To solve this problem, this paper conducts experimental research on ice shedding time under different temperature conditions, simulating the phenomenon of ice shedding during aircraft fight. This work helps formulate the logic of aircraft exiting icing protection mode, and lays a basis for future work of aircraft performance optimization.
Miniaturization design of laser detection device for naval gun composite fuse
Authors: YongqinHuang  , Yang Panxiong , Chen Zuntian 
Published: May 2024

Abstract
Naval gun weapons are the only weapon system on board that can undertake various combat tasks such as shore fire support, sea attack, air defense and missile defense, and rapid response to emergencies. A new type of naval gun laser-radio composite fuse(naval gun composite fuse) is proposed to address the issue of naval gun fuses being susceptible to interference and failure in a single radio proximity system. This improves the multiple operational effectiveness of naval guns and the adaptability of naval gun ammunition to electromagnetic and other interference environments. In response to the limitation of small size of naval gun fuses, the overall structure and miniaturized laser detection device were designed separately. Firstly, a miniaturized 4-channel narrow pulse high repetition frequency laser detection method with uniform forward circumferential distribution is adopted to achieve compatibility with the original naval gun fuse structure, the simulation results indicate that the structural deformation and strength meet the requirements. Secondly, by designing a laser emission collimating lens that is glued together with a small spherical lens and a small concave cylindrical mirror, the outer envelope size is only Φ5x3mm. The simulation results show that at a distance of 20mm from the laser emission window, the spot diameter is 0.66mm and the divergence angle is 1.9 °, achieving good laser collimation and miniaturization of the emission optical system. Finally, the receiving optical system reduces its volume by adding a receiving objective and a field mirror. The effective aperture of the receiving objective is 10mm, the diameter of the field mirror is 5mm, the focal length is 11.1mm, and the receiving field angle is 5 °. The simulation results show that the laser spot radius on the photosensitive surface of the photodetector is 0.06mm, which meets the requirements of photodetectors.
Effects of different deployment strategies on the dynamic characteristics of bidirectional solar array
Authors: Shen Yingyong , Wang Cong , Tan Shiyu , Zhang Ning , Gao Jingbo 
Published: May 2024

Abstract
Based on natural coordinate method, a multi-rigid-body dynamic model of a bidirectional solar array is established. A typical solar array composed of a spacecraft main-body, a yoke, three main solar panels and two side solar panels is utilized as a demonstration case. Three deployment strategies have been designed for bidirectional solar array. Different deployment strategies are evaluated by analysing the attitude and kinetic energy of the spacecraft main-body, angular velocities of deployable components and constraint forces. The simulation results reveal that the strategy of the side panels to be deployed synchronously after the main panels are locked allows the solar arrays to reach a steady state more quickly after entering orbit. The analysis results in this paper can be utilized to aid in the engineering design of solar array deployment.
High-performance subpixel edge location based on FPGA for horizon sensors
Authors: Deng Huajian , Wang Hao , Jin Zhonghe 
Published: May 2024

Abstract
Horizon edge localization accuracy and speed are key factors in the performance of horizon sensors. This paper proposes a high-performance sub-pixel edge localization algorithm base on Field Programmable Gate Array (FPGA) for horizon sensors. The algorithm is carefully designed and simplified according to the computational capabilities and limitations of FPGAs. By making full use of the parallel computing capability of FPGA and carrying out multi-stage pipeline design, the algorithm can complete image acquisition, rough edge localization, sub-pixel edge localization, and projections from pixel points to unit vectors at the same time, which greatly reduces the delay caused by image processing. The experimental results show that FPGA-based image processing shows a significant superiority in terms of speed compared to traditional embedded processors.
A Parameters optimization framework for pose estimation algorithm based on point cloud
Authors: Niu Qun , Wang Ziru , Li Hongkun , Zhao Jieliang 
Published: May 2024

Abstract
Pose estimation using point cloud data is pivotal in robotics. Despite the myriad of algorithms developed for this task, their efficiency is often contingent on optimal parameter settings. Parameters adjustment is a process that traditionally relies on extensive experience and deep understanding of the underlying algorithm. This manual, experience-driven process can hamper the adaptability and performance of pose estimation algorithms. Addressing this limitation, this paper proposes a novel framework for parameter optimization tailored to pose estimation algorithms. The framework introduces an objective function based on pose error, designed to enhance both the algorithm’s number of results and the accuracy. The methodology requires the object model and several scene point clouds with real poses of the objects.By synergistically integrating this objective function with various sampling and pruning algorithms to optimize the pose estimate algorithm, obtaining a set of superior parameters to replace default values becomes a straightforward process. Experimental assessments were conducted on the pose estimation algorithm implemented in Halcon, considering two types of objects within the Industrial 3D Object Detection Dataset (ITODD). The experimental results shown that the number and accuracy of matching results for optimized parameters are better than those proposed by algorithm developers. This not only underscores the framework’s potential as an alternative to conventional manual parameter tuning but also its utility as a foundational configuration for further refinements. Ultimately, the methodology augments the foundational efficiency and versatility of pose estimation algorithms, paving the way for more adept robotic interactions with a myriad of objects.
Scheduling observation tasks for large-scale satellite constellation
Authors: Wen Zhijiang , Liu Yan , Zhang Shengyu , Hu Haiying 
Published: May 2024

Abstract
With the increasing demand for observations and the development of satellite technology, the scale of the Earth Observation Satellites (EOS) constellation is growing. To make the constellation more efficient during operation, scheduling imaging tasks of large-scale constellations is imperative. To solve the scheduling problem, we designed an allocation strategy for the daily operation and a Deep reinforcement learning (DRL) method for in-orbit emergencies. The results show that both of the method is effective.