bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical simulation of response behavior and damage regularity of human lower limbs under axial impact load
Authors: Wang Yuhong , Wang Xianhui , Ma Ning , Zhou Qiang , Wang Jianguo , Sun Xiaowang 
Published: July 2024

Abstract
Axial impacts to the lower extremities of personnel in events such as explosions and falls on the underside of vehicles, which are extremely hazardous to personnel, may result in serious injuries. Most of the current studies on human lower limb injuries from axial loading have not considered the restraining effect of the knee joint. In this paper, based on the THUMS human finite element model, the failure parameters of the tibia, calcaneus, and talus of the lower limb are added and verified. On this basis, the response behavior of the lower limbs of personnel under different axial loads is investigated, and the damage law is further analyzed and studied. It is found that the motion of human lower limbs under axial impact is divided into two phases: the axial motion phase and the rotation phase around the knee joint, and the lower limbs are mainly subjected to compression and bending loads, respectively. The duration of the axial motion phase is related to the impact velocity and the rate of change of velocity and affects the magnitude of tibial force.
Simulation study of jet trajectory based on Runge-Kutta method
Authors: Tang Yaling , Zhao Lei , Zhang Xuefeng 
Published: July 2024

Abstract
To solve the problem of not being able to accurately spray to the designated target point due to wind and distance factors when firefighting at a long distance, this paper adopts the Runge-Kutta algorithm to simulate the trajectory of the fire cannon, and establishes the mathematical model of the trajectory of the jet under the ideal state and the trajectory of the jet under the influence of the wind. We carry out three-dimensional visualization research and compare the results of the simulation experiment with the real experimental data, and the range, height, and trajectory have a high degree of fit. Comparing the simulation results with the real experimental data, the range and height of the jet and the trajectory have a high degree of affinity, and adding the wind power value panel in the visualization interface can simulate the changes of the jet trajectory under different wind speeds and wind power and effectively simulate the trajectory of the jet under natural conditions.
Simulation research of the influence of different representative wavelengths on colorimetric temperature measurement accuracy
Authors: Qi Bowei , Jiang Zhiwei 
Published: July 2024

Abstract
Colorimetric temperature measurement can achieve greater accuracy by obtaining data on the spectral radiance at two representative wavelengths. As color CCD cameras have three pairs of color combinations, the research would explore the accuracy of these three combinations in temperature measurement by simulation research. The stimulation values of the CCD camera for the three primary colors often differ from the three primary color wavelengths specified by the CIE. Therefore, through conducting comparative temperature measurement experiments on simulated objects, the research assesses the accuracy of color temperature measurement by comparing the performance of the CIE-specified wavelengths for the three primary colors with the stimulus values of a color CCD camera. Additionally, this research would also investigate the impact of differences in representative wavelengths on the accuracy of non-grey body temperature measurements.
Exploration of the effect of hot smoke generated by tunnel fire on the ventilation flow field of jet fan
Authors: Peng Xinyi , Zhao Weifeng , Zhang Xinyue 
Published: July 2024

Abstract
To reduce the hazard of hot smoke from tunnel fires, ventilation becomes a necessary control strategy. Uniform ventilation is the main method used in the study of tunnel fires, but it has obvious differences from the widely used jet fan ventilation in practice, and the two have different performances in controlling smoke. Therefore, the distribution of the upstream flow field with jet fan ventilation will be studied in a tunnel fire. Considering several parameters such as the HRR and the velocity of fan exit, numerical simulations were conducted to monitor the fire development by using a Fire dynamics simulator (FDS). The results suggest that the center-line velocity decay of a jet fan can be categorized into three regions: linear decay, power function decay, and stabilization. The decay coefficient (n) related to power function decay correlates with HRR, and therefore, a new prediction for the center-line velocity distribution of the jet fan is proposed. The predicted results correlate well with the available experimental data.
Simulation study on the effect of liquid ammonia spray on the heat transfer performance of multiple heat exchange tubes
Authors: Zhao Shouzheng , Zhao Songsong , Shi Yaoguang , Zhu Zongsheng , Liu Jianyu 
Published: July 2024

Abstract
In this paper, aiming at the problems of low heat transfer efficiency and uneven heat transfer of heat exchange tubes in refrigeration and air conditioning chillers, a liquid ammonia spray cooling method is proposed, and a flow and heat transfer model is established. The distribution of refrigerant droplets in the fluid domain and the heat transfer on the surface of the heat exchange tube are simulated under different spray speeds, spray directions, and double nozzle sprays. The results show that with the increase of spray velocity, the heat transfer performance of heat exchange tubes decreases first and then increases. The effect of spray velocity on the heat transfer performance of each row of heat exchange tubes is not consistent. The farther away it is from the nozzle, the greater the speed corresponding to the peak value of the heat transfer performance improvement of the heat exchange tube will be; the spray direction (gravity) has little influence on the heat transfer performance of the heat exchange tube, which is within 5.1%. Compared with single-nozzle spray, double-nozzle spray greatly improves the heat transfer performance of multi-row heat exchange tubes.
Geometry-based multi-beam survey line layout problem
Authors: Li Chuangqi , Wang Yuhang , Hu Fan 
Published: July 2024

Abstract
The multi-beam measurement system plays a crucial role in ocean mapping and underwater terrain detection. By simultaneously transmitting multiple beams, the system can accurately receive sound waves reflected from the seabed, providing more precise and comprehensive water depth information while effectively revealing the complexity and characteristics of underwater terrain. Under the background and application provided by Question B of the 2023 National Mathematical Contest in Modeling for College Students, this paper investigates the relationship between ocean floor width measurement and factors such as beam position, angle, and slope. Utilizing geometric relations, trigonometric similarity, and sine theorem, a mathematical model is established to determine adjacent strip coverage width and overlap ratio. Furthermore, an optimal strategy is determined by using a greedy algorithm, while binary search backtracking is employed to derive the interval of the next adjacent survey line with the required overlap ratio to obtain an optimal terrain detection strategy.
Simulation and verification of cylinder head’s temperature field for marine low-speed engine
Authors: Hu Lei , Chen Yangfan , Luo Qiang 
Published: July 2024

Abstract
The high load capacity of marine low-speed engines poses a challenge to the thermal load of the cylinder head and temperature field simulation can guide its structural design and optimization. The 3-dimensional models of the fluid domain for the cooling water and the solid domain for the cylinder head are established and meshed, the fluid domain model is simulated to research the heat transfer pattern by Fluent software, and the surface temperature and heat transfer coefficient of the cooling water is calculated. The thermal boundary conditions of the gas in the cylinder are simulated through the analysis of the engine working process. The temperature of the cylinder head is calculated based on the fluid-structure interaction model with the thermal boundary conditions by Workbench software. The validation of the model is carried out by comparing the simulated and measured temperature data in the heated inner wall of the cylinder head. The research results show that compared with the measured value, the error of simulation results is small, which shows that the model and method are reasonable. The temperature in the inner wall of the combustion chamber is low, which can provide possibilities to appropriately improve the power density of the low-speed engine and reduce the risk of low-temperature corrosion.
Investigation of geometrical hopper and initial packing state on the inter-phase momentum transfer with granular flow in vertical packed bed
Authors: Fu Chunpeng 
Published: July 2024

Abstract
For the specific application of vertical packed bed design, the main task is to optimize and improve the granular flow pattern, since a worse granular flow pattern is detrimental to the performance of heat transfer and flow in vertical packed bed. To improve the uniformity of granular flow profiles, an application of the discrete element method is used to investigate the granular flow pattern in a vertically packed bed under the condition of different tapered hopper angles and initial packing states. The uniformity of granular dramatically decreases with an increase in the fluctuation of granular velocity distribution. The variation of structural parameters has a positive influence on enhancing the stability of the granular layer. Coefficient of variation and relative fluctuation kinetic energy are introduced as criteria to describe the stability of the granular layer. This study numerically reveals the evolution of initial packing states has a slight influence on improving the stability of granular flow.
Simulation calculation and optimization of hydraulic buffer device based on Simulink
Authors: Wang Lliuhuo , Hu Sukai , Qi Han , Sun Qiang 
Published: July 2024

Abstract
When the hydraulic cylinder moves at high speed to the end of the stroke, it usually produces severe pressure, shock, and vibration, and makes the system very unstable, so the buffer device is often used to buffer the deceleration process of the hydraulic cylinder. In this paper, the cushioning process of a high-pressure hydraulic cylinder buffer device is modeled mathematically, the motion parameters in the cushioning process are calculated based on Simulink, and different structural parameters of the cylinder block are optimized and compared, to study the influence of structural parameters of the cushioning device on the cushioning process.
Research on the influence of cutting surface characteristics on the cutting load of the conical pick
Authors: Liu Jinxia , Zeng Fanchang , Zhang Chao 
Published: July 2024

Abstract
A coal rock cutting model was established using ANSYS/LS-DYNA and the influence of different cutting surfaces was studied. By using the control variable method, simulation experiments are conducted on single and multiple conical picks cutting under the different ratios of cutting spacing to the cutting thickness. The variation pattern of the cutting correlation is obtained. The conclusion is that when the ratio is 2-2.5, there is a significant cutting correlation between adjacent picks, and the conical picks have the best cutting performance. As the ratio increases, the cutting correlation between adjacent picks weakens, which is not conducive to the cutting of the pick. This conclusion has important guiding significance for the design of cutting parameters.
Dynamic response analysis of ship reef hard grounding
Authors: Liang Enqiang , Kong Jiali , Zheng Minghui , Li Shengtao 
Published: July 2024

Abstract
With the rapid growth of the world economy, the shipping industry has developed rapidly on a global scale, and the water traffic has become increasingly busy. Therefore, the risk of ship transportation has become bigger and bigger, and ship grounding and collision occupy about 50% of the total number of all accidents, among which the consequences of oil tanker grounding accidents are more serious, which not only jeopardize the safety of the personnel but also cause a large area of pollution to the sea. Therefore, it is particularly important to study the ship grounding and collision of oil tankers. Based on the nonlinear finite element software ABAQUS, a calculation model for oil tanker grounding is established, and simplified boundary conditions that can be used for grounding simulation analysis are determined. At the same time, material strain rate sensitivity and material hardening properties are considered. Based on the quasi-static tensile test data of Q235 steel used in ships, material parameters that meet the requirements of collision simulation calculation are calibrated and calculated. The dynamic response of hard grounding is analyzed from both external and internal mechanisms. The research results can provide a reference for improving the grounding collision performance of oil tankers.
Research on predicting air resistance in complex pipelines with fans
Authors: Zhang Shengli , Zeng Zhichun , Sun Yupei , He Long , Wang Changhao 
Published: July 2024

Abstract
This article proposes a prediction method for air resistance in aircraft brake chambers by analyzing the theoretical resistance along the pipeline and local resistance. It develops an air resistance calculation software based on this method. Finally, the air resistance of aircraft brake chamber pipes with three different specifications of fans was predicted using the methods and software presented in this article. The comparison between the predicted results and the simulation results shows that the method is accurate and reliable, and can be used to predict the air resistance inside the aircraft brake chamber.
Simulation analysis of deformation during machining curved thin-walled structures of aluminum alloy
Authors: Zhao Kang , Kong Xiangru 
Published: July 2024

Abstract
Impeller parts are widely used in key parts of equipment such as aerospace, ocean, and energy. Their curved thin-walled structures are prone to local machining deformation and elastic tool yielding during the cutting process, reducing their machining quality. Therefore, to improve the machining accuracy of such parts, an empirical formula and simulation model for cutting force machining are established. Based on the Abaqus secondary development platform, the deformation patterns of parts machining are simulated and predicted, and the machining deformation amounts of different cutting methods are compared and analyzed. The results show that the deformation of single-side cutting is significantly greater than that of symmetrical and stepped cutting, and the maximum deformation is reduced from 0.047 mm to 0.029 mm, which can effectively improve the machining accuracy.
Research on electromagnetic environment inside linear motor
Authors: Li Yunfeng , Su Tianzan , Fu Shanqiang , Ding Sansan , Tang Zhiyuan 
Published: July 2024

Abstract
In the maglev system, the long stator linear motor provides power for the train, and electromagnetic disturbance will be generated during the operation of the motor, which will interfere with other equipment. In this paper, the influence of linear motors on the electromagnetic environment inside the train is analyzed by the finite element method, and the magnetic field intensity inside the train under two different working conditions is obtained by software simulation. It is found that under normal working conditions, the magnetic field radiation emission of the linear motor meets the requirements. Under phase absence conditions, the overall magnetic field intensity on the left side of the car body, the center of the axis, and the right side increases by 12 dB, 17 dB, and 19 dB respectively, so it is necessary to avoid such a situation. This paper further proposes that the external radiation emission of the vehicle can be improved through shielding.
Influence of carbon quantum dots on foam stability: a molecular dynamics study
Authors: Zhao Xingze , Chen Sihang , Zhang Lu , Su Hang , Wu Yining , Ren Hao 
Published: July 2024

Abstract
Carbon quantum dots are employed in foam for enhanced oil recovery. This study focuses on the impact of carbon quantum dots on the stability of oil displacement foam. Molecular dynamics simulations are conducted to investigate commonly used models of carbon quantum dots and surfactant foams in oil displacement. The research delves into the interfacial properties of the foam film, the flow characteristics of water molecules, and the interaction between carbon quantum dots and surfactants. Insights gained from these three aspects reveal the influence of carbon quantum dots on surfactant foam films. This work provides theoretical guidance for the utilization of carbon nanomaterials in foam-assisted oil recovery.
Study on the characteristics of the bypass flow field of the net structure under different Reynolds number conditions
Authors: Yang Liulin , Li Zhaolie , Zhao Tian 
Published: July 2024

Abstract
A double-row crossed cylindrical structure is used as a basic net unit, and the simulation method is used to simulate the winding process of the double-rowed crossed cylinders at different Reynolds numbers, to study and analyze the change of the surrounding flow field with Reynolds number when the uniform flow passes through the net structure, and to compare with the single cylinder. It is found that the fluid passing through the intersection of the cylinders will form a return flow at the back side, and the fluid will extend to the cylinder after the return flow to the near wall of the structure to develop into a spreading flow. The spreading flow makes the distance from the vortex shedding position to the structure surface of the double-row crossed cylinder significantly larger than that of the single cylinder.
Simulation of air pipe heat dissipation in civil aircraft water system based on flowmaster
Authors: Lei Meiling , Zhu Chong 
Published: July 2024

Abstract
The water supply method of civil aircraft water system is mainly from the bleed air system to pressurize the water tank. However, the gas temperature from the bleed air system is often too high. The AC-25.863 draft [1] stipulates that the maximum surface temperature of the equipment should be lower than 50°F below the spontaneous combustion point of flammable liquid in the area. Otherwise, it will become the ignition source of flammable materials. In this paper, by establishing the heat transfer model of an air pipeline, a set of air duct heat transfer calculation methods is proposed, and the variation rule of air pipe surface temperature is studied, to verify that the gas temperature from the bleed air system meets the requirements of the system, and the air pipe surface temperature meets the requirements of AC-25.863 draft.
Research on the influence of system drainage holes on the head loss of water transmission systems
Authors: Li Gaohui , Shang Yan , Gao Yue 
Published: July 2024

Abstract
To ensure the structural safety of the thin lining structure of the tailwater tunnel, this study used three-dimensional flow field numerical simulation technology to conduct an in-depth analysis of the drainage holes set along the tunnel body, to evaluate the impact of drainage holes on the overall and local head loss of the tunnel under different system layout types. It aims to provide scientific theoretical support and practical reference for engineering design and achieve more efficient and stable tunnel hydraulic operation conditions.
Simulation study on the road system of port collection and distribution in the harbor area
Authors: Zhang Jianbao , Zhang Tong , Du Linan , Li Zhenbao 
Published: July 2024

Abstract
This paper comprehensively considers the impact of both internal and external traffic environments on the collection and distribution road system in the harbor area. Utilizing Anylogic simulation software, we construct a test environment using Yulong Port’s collection and distribution scenario as a case study. The analysis examines the influence of changes in road construction and the growth of external traffic on the operational efficiency of the port’s road collection and distribution system. The results indicate that with the addition of new roads, the efficiency of car and freight vehicle operations improves, leading to a respective decrease in the average travel time within the system by 3.6% and 4.4%. However, under conditions where social traffic flow increases to 1.2 times, the average travel time of the traffic flow within the system significantly rises, and congestion occurs in the external traffic around the port. The findings of this research provide valuable decision-making insights for the construction of collection and distribution channels in port areas and the approval of governmental projects.
Research on erosion wear law of four-way flow channel of wellhead fracturing in ultra-deep wells
Authors: Wan Zhiyong , Lian Zhanghua , Sun Wei , An Nan 
Published: July 2024

Abstract
This paper establishes a 1/2 three-dimensional finite element model that considers multiple factors affecting the erosion rate of the four-way fracturing structure on site. The model can simulate the effects of different inlet velocities, dynamic viscosities, outlet quantities, outlet pressures, and channel wall angles on the velocity and streamline distribution of the four-way channel. It is also possible to analyze the effects of different factors such as inlet velocity, sand carrying mass flow rate, inlet quantity, fluid dynamic viscosity, fracturing fluid particle density, fracturing fluid particle diameter, four-way wall hardness, and channel wall inclination angle on the erosion of the inner wall. Through the established model calculation, it was found that as the inlet flow velocity increases, the maximum flow velocity in the channel also increases, and the value is close to 1.8 times the inlet velocity, with the maximum value appearing at the inlet corner. When the inlet velocity of the four-way valve is low, a significant vortex-like flow field appears in the closed flow channel of the four-way valve, which will lead to the accumulation of particles in the fracturing fluid. The calculation shows that the number and velocity of sand containing fracturing fluid inlets have the greatest impact on the erosion rate of the four-way flow channel, and the optimal inclination angle of the flow channel is 9 degrees. Increasing the hardness of the four-way wall can improve the maximum erosion rate of the flow channel wall, but changing the sand particle density and diameter has little significance in reducing the erosion rate of the four-way flow channel. It is recommended to perform corresponding heat treatment on the inner wall of the four-way valve to reduce the impact of sand containing fracturing fluid on wall erosion. This article provides a theoretical basis and guidance for controlling or avoiding erosion and thinning failure of four-way valves and also provides a theoretical basis for the design of wellhead four-way valves and various safe construction operations.