Pub Date : 2024-07-01DOI: 10.1088/1742-6596/2791/1/012033
Shengli Zhang, Zhichun Zeng, Yupei Sun, Long He, Changhao Wang
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.
{"title":"Research on predicting air resistance in complex pipelines with fans","authors":"Shengli Zhang, Zhichun Zeng, Yupei Sun, Long He, Changhao Wang","doi":"10.1088/1742-6596/2791/1/012033","DOIUrl":"https://doi.org/10.1088/1742-6596/2791/1/012033","url":null,"abstract":"\u0000 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.","PeriodicalId":506941,"journal":{"name":"Journal of Physics: Conference Series","volume":"12 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141698670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1088/1742-6596/2796/1/012007
J. Andrade, D. Andrade
The goal of this work is to build a new family of stellar interior solutions in the anisotropic regime of pressure using the framework of gravitational decoupling via minimal geometric deformation. For such purpose, we use a generalization of the complexity factor of the well-known Wyman IIa (n = 1) interior solution in order to close the Einstein’s Field Equations, as well we use the Wyman IIa, Tolman IV, and Heintzmann IIa and Durgapal IV models as seeds solutions. These models fulfill the fundamental physical acceptability conditions for the compactness factor of the system 4U 1820-30. Stability against convection and against collapse are also studied.
{"title":"Stellar models with like-Wyman IIa complexity factor","authors":"J. Andrade, D. Andrade","doi":"10.1088/1742-6596/2796/1/012007","DOIUrl":"https://doi.org/10.1088/1742-6596/2796/1/012007","url":null,"abstract":"\u0000 The goal of this work is to build a new family of stellar interior solutions in the anisotropic regime of pressure using the framework of gravitational decoupling via minimal geometric deformation. For such purpose, we use a generalization of the complexity factor of the well-known Wyman IIa (n = 1) interior solution in order to close the Einstein’s Field Equations, as well we use the Wyman IIa, Tolman IV, and Heintzmann IIa and Durgapal IV models as seeds solutions. These models fulfill the fundamental physical acceptability conditions for the compactness factor of the system 4U 1820-30. Stability against convection and against collapse are also studied.","PeriodicalId":506941,"journal":{"name":"Journal of Physics: Conference Series","volume":"10 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141702754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1088/1742-6596/2791/1/012022
Chuangqi Li, Yuhang Wang, Fan Hu
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.
多波束测量系统在海洋测绘和水下地形探测中发挥着重要作用。该系统通过同时发射多个波束，可以准确接收海底反射的声波，提供更精确、更全面的水深信息，同时有效揭示水下地形的复杂性和特征。在 2023 年全国大学生数学建模竞赛 B 题提供的背景和应用下，本文研究了海底宽度测量与波束位置、角度和坡度等因素之间的关系。利用几何关系、三角相似和正弦定理，建立了一个数学模型，以确定相邻带状覆盖宽度和重叠率。此外，还利用贪婪算法确定了最佳策略，并采用二进制搜索回溯法推导出具有所需重叠率的下一条相邻勘测线的间隔，从而获得最佳地形探测策略。
{"title":"Geometry-based multi-beam survey line layout problem","authors":"Chuangqi Li, Yuhang Wang, Fan Hu","doi":"10.1088/1742-6596/2791/1/012022","DOIUrl":"https://doi.org/10.1088/1742-6596/2791/1/012022","url":null,"abstract":"\u0000 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.","PeriodicalId":506941,"journal":{"name":"Journal of Physics: Conference Series","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141706538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1088/1742-6596/2796/1/012018
David Barrios
The intrinsic and extrinsic scattering and absorption coefficients of a thin black paint substrate used as a solar thermal collector, deposited on a thick glass substrate, were obtained in an approximated single-layer method, using the new solved equations recently determined from the collimated and diffuse differential equations of the four-flux model, for the intrinsic coefficients, and considering the differential equations of the two-flux model with total light intensities, for the extrinsic coefficients. In a first step, the optical constants were determined from the measurements of regular transmittance and specular reflectance, fitting them to the collimated transmittance and reflectance solutions of the four-flux model. In a second step, the intrinsic coefficients were obtained from the diffuse transmittance and reflectance measurements, considering four forward scattering ratios (for collimated and diffuse light intensities and for forward and backward light directions) and two average crossing parameters (for forward and backward light directions). In a third step, the extrinsic coefficients were obtained, using the new solved equations recently determined considering the total differential equations as the sum of the collimated and diffuse differential equations. Due to the approximated single-layer method, a simple rule of three was applied to the intrinsic and extrinsic results, relating the extinction coefficients calculated from the optical constants to those calculated from the collimated differential equations. The same external and internal diffuse interface reflectance was observed by integrating the collimated interface reflectance up to the critical angle of total internal reflection.
{"title":"Parameters of differential equations in four-flux and two-flux models approximated for scattering and absorption results on solar thermal collector black paints","authors":"David Barrios","doi":"10.1088/1742-6596/2796/1/012018","DOIUrl":"https://doi.org/10.1088/1742-6596/2796/1/012018","url":null,"abstract":"\u0000 The intrinsic and extrinsic scattering and absorption coefficients of a thin black paint substrate used as a solar thermal collector, deposited on a thick glass substrate, were obtained in an approximated single-layer method, using the new solved equations recently determined from the collimated and diffuse differential equations of the four-flux model, for the intrinsic coefficients, and considering the differential equations of the two-flux model with total light intensities, for the extrinsic coefficients. In a first step, the optical constants were determined from the measurements of regular transmittance and specular reflectance, fitting them to the collimated transmittance and reflectance solutions of the four-flux model. In a second step, the intrinsic coefficients were obtained from the diffuse transmittance and reflectance measurements, considering four forward scattering ratios (for collimated and diffuse light intensities and for forward and backward light directions) and two average crossing parameters (for forward and backward light directions). In a third step, the extrinsic coefficients were obtained, using the new solved equations recently determined considering the total differential equations as the sum of the collimated and diffuse differential equations. Due to the approximated single-layer method, a simple rule of three was applied to the intrinsic and extrinsic results, relating the extinction coefficients calculated from the optical constants to those calculated from the collimated differential equations. The same external and internal diffuse interface reflectance was observed by integrating the collimated interface reflectance up to the critical angle of total internal reflection.","PeriodicalId":506941,"journal":{"name":"Journal of Physics: Conference Series","volume":"148 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141693122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1088/1742-6596/2796/1/012013
L. Andrade
Engineering can be considered a field of applied physics, as for the design of dynamic systems several aspects such as the strength, parameters of motion, among others, must be estimated for dimensioning, specifications of construction procedures, and operation. In the search for an appropriate model to estimate the dynamic response of a system to a prescribed input, several energy-based methods have been explored over the last decades to address three main issues. Firstly, it is quite rare that a solution for a purely analytical model exists, particularly for complex built-up structures. Secondly, numerical approaches to solve such complex equations of motion of a structure are computationally expensive. Lastly, even if a numerical or analytical solution can be found, there is no warranty that such estimation would be true for an ensemble of nominally identical built-up systems due to uncertainties that are not usually considered by the models. The aim of this work is to present a survey of existing approaches based on equations of energy rather than motion to simplify the computational process and include the effects of uncertainties in the dynamic response, and improvements to such models in regard of other engineering aspects. Additionally, several engineering applications are presented.
{"title":"A Survey on Energy Methods for Vibroacoustic Analysis of Random Dynamic Systems and Applications","authors":"L. Andrade","doi":"10.1088/1742-6596/2796/1/012013","DOIUrl":"https://doi.org/10.1088/1742-6596/2796/1/012013","url":null,"abstract":"\u0000 Engineering can be considered a field of applied physics, as for the design of dynamic systems several aspects such as the strength, parameters of motion, among others, must be estimated for dimensioning, specifications of construction procedures, and operation. In the search for an appropriate model to estimate the dynamic response of a system to a prescribed input, several energy-based methods have been explored over the last decades to address three main issues. Firstly, it is quite rare that a solution for a purely analytical model exists, particularly for complex built-up structures. Secondly, numerical approaches to solve such complex equations of motion of a structure are computationally expensive. Lastly, even if a numerical or analytical solution can be found, there is no warranty that such estimation would be true for an ensemble of nominally identical built-up systems due to uncertainties that are not usually considered by the models. The aim of this work is to present a survey of existing approaches based on equations of energy rather than motion to simplify the computational process and include the effects of uncertainties in the dynamic response, and improvements to such models in regard of other engineering aspects. Additionally, several engineering applications are presented.","PeriodicalId":506941,"journal":{"name":"Journal of Physics: Conference Series","volume":"25 5part1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141702177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1088/1742-6596/2791/1/012030
Va Kong, Xiaoguang Wang, Qiong Wang, Zhen Li, Hongbing Chen, Jiang Wang
As prefabricated construction advances, the enhanced informatization and the industrialized modular construction method of MIC (Modular integrated construction) shear walls have been widely applied in real projects. MIC shear walls are generally made up of prefabricated wall modules with varying strength grades, using concrete of various ages, and are combined with cast-in-place concrete. Due to the unique construction requirements of these walls, defects such as interfacial delamination and internal voids might occur, arising from factors like concrete shrinkage and creep, complex interfacial structures, inadequate compaction during vibration, and construction process issues. Since these interfacial defects cannot be visually inspected from the exterior, developing non-destructive testing (NDT) methods specifically for detecting such defects in shear walls becomes an urgent necessity. This paper utilizes a combination of theoretical analysis and numerical simulation to explore the vibration modes of MIC shear walls with hidden defects. First, a theoretical model is proposed for the local vibration modes of MIC shear wall shells with consideration of interfacial delamination defects. Then, a numerical simulation model is established based on MIC shear wall construction and defect features to simulate the vibration behavior accurately. Finally, after examining the theoretical and simulated vibration characteristics of MIC shear walls, a significant theoretical foundation is established for identifying interfacial defects in MIC shear walls.
随着预制建筑的发展，MIC（模块化集成建筑）剪力墙的信息化和工业化模块化施工方法已在实际工程中得到广泛应用。MIC 剪力墙一般由不同强度等级的预制墙体模块组成，使用不同龄期的混凝土，并与现浇混凝土相结合。由于这些墙体的特殊施工要求，可能会出现界面分层和内部空隙等缺陷，产生这些缺陷的因素包括混凝土收缩和徐变、复杂的界面结构、振捣时压实不足以及施工工艺问题等。由于无法从外部目视检查这些界面缺陷，因此迫切需要开发专门用于检测剪力墙中此类缺陷的无损检测（NDT）方法。本文采用理论分析和数值模拟相结合的方法来探讨存在隐蔽缺陷的 MIC 剪力墙的振动模式。首先，提出了考虑界面分层缺陷的 MIC 剪力墙壳体局部振动模式的理论模型。然后，根据 MIC 剪力墙的结构和缺陷特征建立了数值模拟模型，以准确模拟其振动行为。最后，在研究了 MIC 剪力墙的理论和模拟振动特性后，为识别 MIC 剪力墙中的界面缺陷奠定了重要的理论基础。
{"title":"Theoretical and simulation study on the vibration modes of shear walls in prefabricated modular construction","authors":"Va Kong, Xiaoguang Wang, Qiong Wang, Zhen Li, Hongbing Chen, Jiang Wang","doi":"10.1088/1742-6596/2791/1/012030","DOIUrl":"https://doi.org/10.1088/1742-6596/2791/1/012030","url":null,"abstract":"\u0000 As prefabricated construction advances, the enhanced informatization and the industrialized modular construction method of MIC (Modular integrated construction) shear walls have been widely applied in real projects. MIC shear walls are generally made up of prefabricated wall modules with varying strength grades, using concrete of various ages, and are combined with cast-in-place concrete. Due to the unique construction requirements of these walls, defects such as interfacial delamination and internal voids might occur, arising from factors like concrete shrinkage and creep, complex interfacial structures, inadequate compaction during vibration, and construction process issues. Since these interfacial defects cannot be visually inspected from the exterior, developing non-destructive testing (NDT) methods specifically for detecting such defects in shear walls becomes an urgent necessity. This paper utilizes a combination of theoretical analysis and numerical simulation to explore the vibration modes of MIC shear walls with hidden defects. First, a theoretical model is proposed for the local vibration modes of MIC shear wall shells with consideration of interfacial delamination defects. Then, a numerical simulation model is established based on MIC shear wall construction and defect features to simulate the vibration behavior accurately. Finally, after examining the theoretical and simulated vibration characteristics of MIC shear walls, a significant theoretical foundation is established for identifying interfacial defects in MIC shear walls.","PeriodicalId":506941,"journal":{"name":"Journal of Physics: Conference Series","volume":"89 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141699345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1088/1742-6596/2791/1/012070
Ting Lei, Jiepeng Yang, Shizhang Liang
For the reason of reliability improvement of BGA solder, ANSYS is used to establish a BGA solder model that contains information such as size, material, grid, etc. The thermal stress of solder is selected as the optimization objective by the optimization parameters of solder height, solder radial direction, and spacing of solder. Response surface methodology is used to design 17 sets of different level parameters for simulation calculations, and a regression equation between solder joint stress and optimization parameters is established to obtain the parameter combination with the minimum stress of solder. The analysis results show that the corner solder far from the chip are critical solder joint for failure. The optimized solder joint parameters are as follows. The solder height is 0.5 mm, the solder radial is 0.6 mm, and the solder spacing is 1 mm. The optimized solder joint stress value is 30.818 MPa, which reduces the stress by 27.71% compared to before optimization, which achieved the reliability improvement of BGA solder.
{"title":"Reliability analysis and optimization of BGA solder based on finite element simulation","authors":"Ting Lei, Jiepeng Yang, Shizhang Liang","doi":"10.1088/1742-6596/2791/1/012070","DOIUrl":"https://doi.org/10.1088/1742-6596/2791/1/012070","url":null,"abstract":"\u0000 For the reason of reliability improvement of BGA solder, ANSYS is used to establish a BGA solder model that contains information such as size, material, grid, etc. The thermal stress of solder is selected as the optimization objective by the optimization parameters of solder height, solder radial direction, and spacing of solder. Response surface methodology is used to design 17 sets of different level parameters for simulation calculations, and a regression equation between solder joint stress and optimization parameters is established to obtain the parameter combination with the minimum stress of solder. The analysis results show that the corner solder far from the chip are critical solder joint for failure. The optimized solder joint parameters are as follows. The solder height is 0.5 mm, the solder radial is 0.6 mm, and the solder spacing is 1 mm. The optimized solder joint stress value is 30.818 MPa, which reduces the stress by 27.71% compared to before optimization, which achieved the reliability improvement of BGA solder.","PeriodicalId":506941,"journal":{"name":"Journal of Physics: Conference Series","volume":"29 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141701349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1088/1742-6596/2791/1/012023
Lei Hu, Yangfan Chen, Qiang Luo
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.
{"title":"Simulation and verification of cylinder head’s temperature field for marine low-speed engine","authors":"Lei Hu, Yangfan Chen, Qiang Luo","doi":"10.1088/1742-6596/2791/1/012023","DOIUrl":"https://doi.org/10.1088/1742-6596/2791/1/012023","url":null,"abstract":"\u0000 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.","PeriodicalId":506941,"journal":{"name":"Journal of Physics: Conference Series","volume":"21 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141704005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1088/1742-6596/2791/1/012012
Zewei Ma
To improve the local microenvironment of the human body in industrial buildings with strong heat sources, this paper proposes a new personalized air supply method based on the attachment effect. The numerical simulation method is used to study the influence of heat source intensity on the inhaled air quality in this paper. Studies have shown that when the air supply speed is less than or equal to 0.5 m/s, the fresh air ratio decreases as the Gr number of the heat source increases. When the air supply speed is greater than or equal to 0.7 m/s, the fresh air ratio increases as the Gr number of the heat source increases.
为改善强热源工业建筑中的人体局部微环境，本文提出了一种基于附着效应的新型个性化送风方法。本文采用数值模拟方法研究了热源强度对吸入空气质量的影响。研究表明，当送风速度小于或等于 0.5 m/s 时，随着热源 Gr 数的增加，新风比降低。当送风速度大于或等于 0.7 米/秒时，新风比会随着热源格数的增加而增加。
{"title":"Simulation study on the impact of heat source intensity on the inhaled air quality of an innovative personalized air supply method","authors":"Zewei Ma","doi":"10.1088/1742-6596/2791/1/012012","DOIUrl":"https://doi.org/10.1088/1742-6596/2791/1/012012","url":null,"abstract":"\u0000 To improve the local microenvironment of the human body in industrial buildings with strong heat sources, this paper proposes a new personalized air supply method based on the attachment effect. The numerical simulation method is used to study the influence of heat source intensity on the inhaled air quality in this paper. Studies have shown that when the air supply speed is less than or equal to 0.5 m/s, the fresh air ratio decreases as the Gr number of the heat source increases. When the air supply speed is greater than or equal to 0.7 m/s, the fresh air ratio increases as the Gr number of the heat source increases.","PeriodicalId":506941,"journal":{"name":"Journal of Physics: Conference Series","volume":"55 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141712641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1088/1742-6596/2791/1/012054
Zhaoqiang Li, Haijun Yang, Lingling Wang, Wendong Ji
In this paper, a short-circuit fault simulation of a ship’s electrical power system is carried out based on Simulink. According to the power system sketch of the ship, a simulation model is built, initial conditions are set, two-phase short-circuit faults and three-phase short-circuit faults are simulated, and the simulation results are analyzed. The results show that the short-circuit fault has a large impact on both the generator side and the load side, in which the impact on the load side is more serious. At the generator side, the voltage of the corresponding phase drops by about 1/3-1/2, and the current increases by about 1.5 times. At the load side, when a two-phase short circuit occurs, the voltage drops to half of the original one, and when a three-phase short circuit occurs, the voltage drops to 0. The short-circuit current has the largest value at the beginning of the short circuit, then oscillates and decays, and finally stabilizes at about 15 times the normal working current.
{"title":"Simulation and analysis of short circuit fault in ship power system based on simulink","authors":"Zhaoqiang Li, Haijun Yang, Lingling Wang, Wendong Ji","doi":"10.1088/1742-6596/2791/1/012054","DOIUrl":"https://doi.org/10.1088/1742-6596/2791/1/012054","url":null,"abstract":"\u0000 In this paper, a short-circuit fault simulation of a ship’s electrical power system is carried out based on Simulink. According to the power system sketch of the ship, a simulation model is built, initial conditions are set, two-phase short-circuit faults and three-phase short-circuit faults are simulated, and the simulation results are analyzed. The results show that the short-circuit fault has a large impact on both the generator side and the load side, in which the impact on the load side is more serious. At the generator side, the voltage of the corresponding phase drops by about 1/3-1/2, and the current increases by about 1.5 times. At the load side, when a two-phase short circuit occurs, the voltage drops to half of the original one, and when a three-phase short circuit occurs, the voltage drops to 0. The short-circuit current has the largest value at the beginning of the short circuit, then oscillates and decays, and finally stabilizes at about 15 times the normal working current.","PeriodicalId":506941,"journal":{"name":"Journal of Physics: Conference Series","volume":"43 179","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141696503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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