bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Investigation of the transient process of direct collision between two droplets
Authors: Liu C C 
Published: November 2024

Abstract
The use of spray systems finds widespread applications in fields such as national defense and industry. These systems are employed for spray cooling, spray forming, spray coating, and inkjet painting. Within spray systems, atomized droplets play a crucial role, either impacting surfaces or colliding with each other. Understanding the impact process of these droplets is essential for optimizing spray system performance. In this study, computational simulations focus on direct collision of two droplets. Numerical methods are employed, including structured single-block and staggered grid systems for discretizing the spatial domain. The finite volume method iteratively solves the governing equations of mass and momentum. The coupling between velocities and pressure is handled using SIMPLER methods. During droplet collision, phenomena like deformation, breakup, and merging occur at the boundary. To accurately capture these movements, a level set function approach is utilized. Numerical simulations of a water droplet impinging on a flat surface are compared with experimental results for verification. When two droplets collide head-on with the same Reynolds number and Weber number, they merge into a single oscillating droplet at a fixed position. Increasing the Reynolds number of the two colliding droplets intensifies the oscillation phenomenon in the merged droplet. Even when two droplets collide at an angle or have different sizes, they still merge into a single oscillating droplet. The merged droplet moves in a direction where the original two droplets’ momentum cannot be fully offset.
A revolutionary approach to automate labelling of CAD files
Authors: Chen T C , Chang T H , Lee J C 
Published: November 2024

Abstract
This innovation represents a significant advancement in enhancing processing efficiency when dealing with engineering drawings. Traditionally, the review of customer drawings needs to be executed by experienced experts before manufacture. The identification and labelling of key features were reliant on human intervention for subsequent Design for Manufacturability (DFM) or G-code programming. However, the previous method not only consumed valuable time but also introduced the potential for human errors. In this context, we introduce a high-efficiency technology for recognizing engineering drawings, automatically labelling key features, and converting unstructured data into structured data. It is noteworthy that this technology distinguishes itself from traditional methods, such as R-CNN or similar neural network approaches and differs from pre-labeled engineering drawings reliant on experts manually inputting keywords for dimensions or layers. This work is a vital step towards the realization of intelligent manufacturing. For instance, our customers can now review engineering drawings online and receive immediate feedback. This online interaction is facilitated by processing structured data, a direct output of this presented technology, with other specific modules. Furthermore, the structured data seamlessly integrates into subsequent manufacturing procedures, including notifying the supply chain, generating 3D drawings, and CNC programming. In conclusion, this technology showcases its significance in advancing our vision of intelligent manufacturing at ZY Corp.
An efficient face and mask detection by embedded device via thermal imaging camera
Authors: Wu R C , Xu H W , Wang S Y 
Published: November 2024

Abstract
Since 87.9% of COVID-19 patients develop a fever symptom, the mandatory wearing of masks, temperature screening, and isolation of individuals with fever are the most import methods for community epidemic prevention. This study develops a thermal imaging thermometer embedded system with face, face mask, and temperature detection capabilities using low-end CPU devices. The hardware includes a Raspberry Pi 4, FLIR Lepton 3.5 LWIR Micro Thermal Camera Module, display screen, and alarm. The system is characterized by its low cost and lightweight design, and it only needs to detect necessary areas around the face area during face mask and temperature detection, effectively avoiding external interference and further enhancing the effectiveness of epidemic prevention. The face detection model is based on the YOLO-Fastest architecture and has been improved, referred to as Pi-fast. In terms of performance on the training and testing sets, our proposed Pi-fast achieves Mean Average Precision (mAP) values of 99.64% and 93.18%, F1 score values of 0.94 and 0.87, and Intersection over Union (IoU)values of 78.07% and 65.98%, respectively. Regarding system performance, the frame rate of FLIR Lepton 3.5 Thermal Camera Module hardware specifications is 8.7 FPS. When using YOLO-Fastest and proposed Pi-fast model for detection on the proposed thermal imaging system, the frame rates are 6.58 FPS and 7.32FPS, respectively. The proposed Pi-fast model outperforms YOLO-Fastest about 0.74 FPS (11.2%). The system can detect objects at a distance of about 7 meters from the lens in thermographic camera with a resolution of only 160×120 pixels, making it suitable for multi-person screening and improving the screening process’s efficiency. The system can effectively perform temperature screening and face mask detection, making it suitable for office buildings, schools, medical clinics, and other public areas. During the severe epidemic period, the proposed thermal imaging embedded system that was actually used for epidemic prevention work at I-Shou University, improving screening efficiency and reducing labour costs.
Thread plate posture analysis for screw rolling adjustment design
Authors: Wen C C , Chang C T , Yang T D 
Published: November 2024

Abstract
This research focuses on process design of the adjustment of movable thread plate and fixed thread plate in the screw rolling machine during production. By observing some key dimensions of the threaded screw, one can determine the movement amount and the rotation direction of the adjustment screw bars mechanism of the fixed thread plate that required for the specified size of this type of screw. One establishes a relationship from the adjustment of the screw bars mechanism to the fixed thread plate posture. It can be seen that the formed screw size deviations will lead the machine operator to adopt one of the proposed process to achieve the posture adjustment of the fixed thread plate. While the screw specification deviations do not conform to the standard ones, the operator just need to find out the error type of the formed screw and measures its specification to follow one of the proposed formulas, then the wrong thread plate posture can be modified to the correct posture under operator’s adjustment. The method addressed in this research can not only reduce the operational difficulty of screw thread rolling machine but also can reduce the trial-and-error processes in traditional operation methods.
Numerical study on machining of Al/SiC composite materials
Authors: Fann K J , Lu Y T 
Published: November 2024

Abstract
Metal matrix composites (MMCs) comprising aluminum (Al) matrices reinforced with silicon carbide (SiC) particles have garnered significant attention in recent years due to their outstanding specific strength, stiffness, corrosion resistance, and thermal conductivity. However, to achieve the desired geometry and shape of such MMC workpiece, a cutting process is still necessary, which involves a complex phenomenon of mechanical interactions that can result in surface defects and reduced tool life. This study aims to numerically investigate the cutting process of Al/SiC MMC workpieces in a manner that closely resembles reality by developing a finite element model directly from a metallographic image of a composite with a 30% volume fraction of 10 μm SiC grit. The research focuses on the effects of cutting depth, cutter rake, and the interaction between the cutting tool and the SiC particles. The results demonstrate that, depending on the contact point with the SiC particle, there is a variation in the cutting force generated when the cutter tip encounters the SiC particle. This causes the particle to break, rotate, roll over the matrix, and embed deeper into the matrix. Furthermore, based on the analysis of variance applied to the cutting force, the cutting depth exhibits a significant influence, while the cutter rake shows no significant effect on the cutting force.
ANCF-based modelling of rigid-flexible coupling of helicopter flexible rotor blades
Authors: Mei Xiaohan , Gu Haiyu , Wei Cheng 
Published: November 2024

Abstract
A high-precision rotor structure dynamic model applicable to a variety of helicopter blade hub structures is established considering rotor blade flexible deformation. The absolute nodal coordinate method is applied to the traditional rotor blade rigid-flexible coupling dynamics model, making the new model applicable to both fully articulated rotor blades and other advanced blade hub structures. No small-volume assumptions were made in the modelling process. Both Green’s strain expression under finite deformation and the geometrical relation of elastic deformation motion based on the absolute nodal coordinate method are used to derive the blade strain energy, kinetic energy, and the external load virtual work. The rotation angle at the articulation constraint at the root of the blade coupled with the elastic deformation degrees of freedom of the blade in three independent rigid body degrees of freedom, respectively. The rotor blade rigid-flexible coupling dynamics equations were established according to the Hamilton action principle. The time-domain simulation is carried out under a free single pendulum and fixed rotational speed/fixed torque for the established flexible blade model, which verifies the validity and high accuracy of the rigid-flexible coupling articulation model of the flexible rotor blade and the blade hub.
Conceptual design and optimization of a hydrogen-powered aircraft with a dorsal tank layout
Authors: Guo Yuan , Chow Jun , Chen Hao , Qiao Xiaotao , Fan Chuning 
Published: November 2024

Abstract
The application of hydrogen as a clean energy source is revolutionizing the aerospace industry, especially in the design and optimization of next-generation aircraft. In this study, a tubular-wing hydrogen-powered aircraft is designed based on a modified Boeing 737 configuration with a dorsal fuselage tank layout. During the design process, the fuselage was parametrically reconstructed to accommodate tanks of different sizes; Subsequently, a multidisciplinary optimization of the hydrogen aircraft was carried out with fuel consumption as the optimization objective. During the optimization process, dynamic mission profiles were introduced to make the fuel consumption calculation more accurate. Finally, this paper compares and analyzes the differences between kerosene-powered and hydrogen-powered aircraft. The results show that the hydrogen airplane has an increase in weight of about 10% and a decrease in lift-to-drag ratio of 1 to 2 units. To offset these effects, a hydrogen airplane would need to be designed with a larger aspect ratio and provide more thrust during flight. Nonetheless, the results also show that, because of the high calorific value of liquid hydrogen, the total energy consumption of the designed hydrogen aircraft is lower than that of a kerosene aircraft for the same range.
Research on evaluation technology for fuel tank inerting system based on task profile
Authors: Wang Zhaoruijia 
Published: November 2024

Abstract
The flammable and explosive characteristics of aviation fuel have always made the safety of aircraft fuel tanks a focus of attention in the aviation industry. At present, all aircraft test flights in our country require the completion of the evaluation of the fuel tank inerting subsystem, which has put forward clear requirements for the measurement of oxygen concentration in aircraft fuel tanks, and corresponding technical indicators have been developed based on the usage of civil and military aircraft. This article establishes a digital model of the aircraft fuel tank inerting system based on AMEsim software, verifies the accuracy of the model through literature data, and uses the digital model to study the variation law of oxygen concentration in the fuel tank. The temporal variation of oxygen concentration in the gas-phase space of aircraft fuel tanks is analyzed under different nitrogen-rich gas concentrations, nitrogen-rich gas flow rates, fuel tank loading rates, and aircraft descent rates. Based on the temporal variation of oxygen concentration, a reference is provided for formulating flight test methods.
Research on identification and quantification methods for loss sources of compressors
Authors: Liu Liangye , Yi Weilin 
Published: November 2024

Abstract
A deep understanding of the internal loss mechanisms and specific values of turbomachinery is crucial for its design and analysis. In this paper, based on the theory of entropy production, the loss sources in the NASA Rotor67 transonic fan and Radiver centrifugal compressor were quantified by using numerical simulation methods and physical flow characteristic description methods. The proportion of losses in various regions was presented. The results show that in the transonic fan, boundary layer losses and wake losses account for more than 70%, while direct shock losses account for less than 2%. Additionally, as the mass flow increases, the losses gradually move downstream, with the proportion of wake losses increasing. Within the wake losses, the influence of tip leakage flow and corner separation flow exceeds 70%. In the centrifugal compressor, as the mass flow decreases, the proportion of impeller losses to the total stage losses increases significantly, from 21.7% at the choking condition to 63.5% near the design condition. Most of the losses within the impeller occur near the casing area, accounting for about 47% of the impeller losses. The areas near the blades and the main flow area are the other two major sources of impeller losses, with both contributing to 36% of the losses.
Traveling wave vibration characteristics of rotating FGM conical shell
Authors: Zhao Changying , Sun Shupeng , Tartibu Lagouge , Han Hesheng 
Published: November 2024

Abstract
Conical shell is common structural component in various rotating machinery. The study of traveling wave vibration performance of conical shell is of great significant for the design of rotating machinery. This paper addresses the traveling wave vibration performance of rotating functionally graded material (FGM) conical shells. Artificial springs, uniformly distributed, are employed to simulate the boundary constraints of rotating FGM conical shell. Accounting for the effects of Coriolis and centrifugal forces caused by rotation, the energy equation of rotating FGM conical shell is calculated, and then the dynamical model of the rotating FGM conical shell under elastic supported constraints is established using the Lagrange equation. The influence of key factors on traveling wave frequency and response characteristics of rotating FGM conical shell are investigated including rotational speed, half-cone angle and material components.
Periodic orbits of solar sails in the Sun-Earth system
Authors: Liu Lei , Zhang Xin 
Published: November 2024

Abstract
This paper studies the periodic orbits of solar sails using reflectivity control devices (RCDs) in the circular Sun-Earth system. Significantly, the dynamical equations about the solar sail are given separately in the rotational coordinate system and adjoint coordinate system. Analytical solutions about the periodic orbits of solar sails are given. So as to gain the periodic orbits of solar sails, we discuss the conditions of the attitude angles and reflectivity modulation ratio of solar sails. This paper simulates some periodic orbits of solar sails and analyzes the stability of a periodic orbit of a solar sail by using the Floquet theory. The outcomes show that it is unstable for the periodic orbit of a solar sail. Based on the linear quadratic regulator (LQR), this paper designs a control algorithm to achieve tracking in the target orbit of solar sails.
Numerical simulation of fuselage sliding on calm water for an amphibious aircraft based on global moving mesh method
Authors: Gao Xianjiao , Sang Tengjiao , Li Xu , Qu Rujun , Han Xiaohong 
Published: November 2024

Abstract
Aiming at the large motion fluctuation of fuselage sliding on calm water, a numerical simulation method based on the global moving mesh method is introduced by using the computational fluid dynamics software of STAR-CCM+, the two equations SST k-w turbulence model to solve the RANS equations, the VOF method to capture free surface, the DFBI module to simulate the movement of the fuselage. We established a simulation scheme on the sliding movement of the fuselage on calm water, which effectively solves the problem of calculation divergence caused by the excessive stretching deformation of the mesh. Comparison between calculation results and model test results shows that the trends of resistance and attitude angles changing with velocity are basically the same, and the relative errors are around 10%, which indicates that the global moving mesh method is feasible in the simulation of fuselage sliding on calm water.
Solar sail transfer strategy for long-duration multi-objective mission in cislunar space utilizing solar radiation and reflectivity control device
Authors: He Guanwei , Zhang Binbin , Wu Jun 
Published: November 2024

Abstract
This study delves into the complexities of optimizing solar sail trajectories for long-duration multi-objective missions in cislunar space, focusing on orbital transfers between halo orbits and distant retrograde orbits. It presents an innovative transfer strategy that integrates solar radiation propulsion and reflectivity control devices to effectively adjust thrust force magnitude and direction, thereby improving maneuver capabilities. The optimization method is founded on the coupled dynamics of a solar sail, aiming to minimize the transfer time of flight using the Hermite-Simpson collocation method while ensuring optimal performance. Through thorough analysis and comparison, the research strives to determine the most efficient trajectory for solar sail orbital transfers in cislunar space.
Stability analysis of micro-probe landings in complex terrain
Authors: Cheng Zhen , Zhang Yuanxun , Qing Wushi , Zhang Baogui 
Published: November 2024

Abstract
Addressing the problem of landing stability of the micro-probes on the surface of extraterrestrial objects, combined with the geometric properties of the orthotetrahedron, this paper proposes a structural design method of the four-spine microprobe landing bracket that can adapt to the complex terrain and carries out the analysis of the landing stability of the four-spine bracket under the state of three-legged landing and the optimization of the structure for combined terrain of stones and slopes. Referring to the ZMP theory, the harsh working conditions of the four-spine bracket when landing are sorted out and determined. Based on the kinematics theory, the collision mechanism between the four-spine bracket and the ground is analyzed, and a landing model suitable for the micro-probes is established, which provides the basis for determining the landing stability of the micro-probe. Around the collision mechanism and landing model, the dimension optimization of the four-spine bracket is carried out, and the results of Adams dynamics simulation analysis and prototype test show that the landing stability of the four-spine bracket is improved, which verifies the validity of the optimization idea.
Characterizing the contact force of a high-speed rotating fluid on brush wire
Authors: Li Tian , Wu Jiang , Zhong Jiangying , Guo Zhijun , Fu You 
Published: November 2024

Abstract
To study the effect of coolant fluid on rotor-brush wire contact in high-speed conductive slip rings, the rotor-brush wire contact model is simplified to two cylindrical vertical contacts. The theoretical formula of the force on the near-wall surface of the brush wire is derived by combining the distribution of the characteristics of the cylindrical rotating fluid domain. A three-dimensional model of high-speed rotor-brush wire fluid-solid coupling is created. The initial preload and coolant disturbance on the near-wall surface of the brush wire is considered to analyze the force characteristics of the brush wire. The force characteristics of the near-wall surface and the three-dimensional surface velocity cloud diagram of the fluid domain are obtained. The results show that the growth rate of the fluid domain force on the wall surface of the brush wire increases with the increase of rotational speed. A change of only 0.5 mm near the wall leads to a change of nearly 40% in the speed.
Analysis of the effects of combined suction on hypersonic inlet starting performance
Authors: Peng Siyi , Xu Shangcheng , Wang Yi 
Published: November 2024

Abstract
Taking a two-dimensional inlet (Case 1) as the original inlet, the combined suction schemes are designed and their influences on the self-starting ability of the inlet are studied. The flow fields at the design point and the self-starting progress of the inlets are calculated by the numerical simulation method. The results show that the three-slot combination scheme (Case 2) leads to the reduction of the mass flow rate of the throat at the design point by 1.15% and the increase of the total pressure recovery coefficient by 6.73%. The self-starting Mach number of the inlet decreases from 4.6 to 3.2, which indicates that the self-starting ability is improved significantly by the three-slot combination scheme.
In order to illustrate the role of each slot in improving the self-starting ability, three two-slot combination schemes, which are called Case 3, Case 4, and Case 5, are set up by closing Slot 1, Slot 2, and Slot 3 in turn and their self-starting processes are simulated. The results indicate that the self-starting Mach numbers of Case 3, Case 4, and Case 5 are 3.6, 4.1, and 4.5 respectively, which are 0.4, 0.9, and 1.3 higher than that of Case 2 respectively. Slot 3 has the greatest influence on the self-starting ability. When the incoming Mach number rises to 4.2, a closed separation zone is induced between Slot 2 and the throat by the reflected shock wave on the cowl side of Case 5. Due to the lack of lip overflow, which is an important flow regulation mechanism, the separation zone has a strong self-sustaining ability, and the inlet keeps unstart until the incoming Mach number rises to 4.5. In addition, in the absence of Slot 1 or Slot 2, the large-scale separation zone will not disappear until the incoming flow pressure increases to a certain value.
Fluid-thermally-solid coupling analysis of aircraft leading edge
Authors: Kang Xiaozhi , Du Lin , Shi Qinchuan , Wang Xiaoyu 
Published: November 2024

Abstract
Aircraft are affected by aerodynamic loads during operation. To analyze the impact of the leading edge structure of aircraft under different flight angles of attack, this paper uses the fluid-heat-solid coupling calculation method. It combines CFD with the thermal-structure field solver and uses simulation software, with a flight altitude of 15 km, flight speed of 6 Ma, and flight Angle of attack of 0 ~ 20°. Considering the change of material parameters with temperature, the coupling of multiple physical fields in aircraft is simulated and analyzed. The simulation results show that the existence of the flight angle of attack makes the flow field shock wave position of the aircraft closer to the windward surface of the structure. The angle of attack exacerbates the structural deformation of the aircraft, with the maximum deformation occurring at a 20° angle of attack, which is 3.06 mm. The research results can provide a reference for aircraft design.