Article
Automation & Control Systems
Wen Peng, Xi Chen, Qinglong Wang, Zilong Wan, Jie Sun, Dianhua Zhang
Summary: An accurate description of metal flow behavior during wedge zone deformation is crucial for the stability of endless strip production rolling process. A flatness calculation model of the wedge zone, considering the metal transverse flow, was established to predict the flatness distribution during the flying gauge change process. The effects of different rolling parameters on metal flow in the wedge zone were investigated using a combination of this model and a 3D finite element model, and the influences of reduction rate, roll crown, and friction coefficient on flatness and metal lateral flow were analyzed.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Xu Hua, Li Wang, Shanshui Yang
Summary: In this article, a multiscale simulation method is used to analyze the aging mechanism of cable insulation and reveal the variation law of aging characteristics. The study finds that tiny molecular products resulting from thermal and electrical aging are the main factors causing changes in dielectric constant and electrical conductivity. The multiscale analysis method improves the efficiency of cable insulation aging analysis, providing a theoretical basis and data support for cable fault diagnosis and remaining useful life prediction.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2023)
Article
Engineering, Electrical & Electronic
Amid Shahbazi, Jamshid Aghaei, Sasan Pirouzi, Taher Niknam, Vahid Vahidinasab, Miadreza Shafie-khah, Joao P. S. Catalao
Summary: This paper proposes a two-objective linearized resilient architecture (LRA) model for distribution networks to achieve a strictly resilient network during natural disasters. The model minimizes planning and operation costs, load shedding, and repair costs to obtain an equivalent single-objective LRA model through e-constraint-based Pareto optimization. Numerical simulation confirms the capability of the proposed method in obtaining a resilient distribution network during natural disasters.
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
(2021)
Article
Multidisciplinary Sciences
Osamah Al-Dori, Betul Sakar, Atilla Donuk
Summary: This study provides robust guidelines for researchers and designers to precisely estimate losses and leakage reactance in distribution transformers. Analytical and numerical methods are used to estimate transformer lifespan and improve grid quality during the design stage.
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Josef Novak
Summary: This study investigates the polarization process on resonators with electrodes incompletely covering their bases, using a Finite Element Model to analyze the relationship between the inhomogeneous electric field and polarization. The research identifies areas within the resonator where desired polarization occurs and where no polarization occurs.
APPLIED SCIENCES-BASEL
(2021)
Article
Materials Science, Multidisciplinary
Jehad Alzabut, Sohail Nadeem, Sumaira Noor, Sayed M. Eldin
Summary: This article investigates the modeling and numerical simulation of Magnetohydrodynamic (MHD) buoyancy driven convection flow in a differentially heated, square enclosure. Numerical solutions are computed for different values of Rayleigh number ranging 103 < Ra < 107 and Hartmann number ranging 0 < Ha < 40. Comportment of MHD free convection heat flow from transient to steady state is numerically examined for a period of 0 to 1 s. It is seen that with increasing values of Rayleigh number there is increase in local Nusselt number distribution on heated side of the cavity, while velocity distribution in the flow domain decreases with increasing Hartmann number.
RESULTS IN PHYSICS
(2023)
Article
Mathematics
Alin Dragomir, Maricel Adam, Mihai Andrusca, Gheorghe Grigoras, Marian Dragomir, Seeram Ramakrishna
Summary: This paper proposes a mathematical modeling approach to determine the permanent regime temperature of an electric contact in the railway electric traction supply system. The numerical modeling method used for determining the electric contact temperature serves as the basis for developing a finite-element thermal model. The simulation of the electric contact was validated by experimental infrared investigation, showing good synchronization between calculated, simulated, and measured temperatures.
Article
Engineering, Electrical & Electronic
Rahul Ranjan Jha, Adedoyin Inaolaji, Biswajit Dipan Biswas, Arun Suresh, Anamika Dubey, Sumit Paudyal, Sukumar Kamalasadan
Summary: In power distribution systems, the optimal power flow (D-OPF) is a non-convex and non-linear programming problem. Convex relaxation and linear approximation models are used for computational efficiency, but they have different assumptions, performance, and may yield physically meaningless solutions. This study compares the performance of second-order cone programming (SOCP), semi-definite programming (SDP), and linear programming (LP) approaches for D-OPF, evaluating their feasibility, optimality, and scalability compared to NLP-based formulations. The study also compares bus injection and branch flow based on NLP formulations. Evaluations are conducted on small, medium, and large distribution feeders, showing that the feasibility and exactness of relaxed D-OPF formulations depend on the problem type, some NLP formulations are more computationally tractable, different NLP formulations can converge to different local solutions, and the linear model may underestimate or overestimate the cost function and lead to AC-infeasible solutions.
IEEE TRANSACTIONS ON POWER SYSTEMS
(2023)
Article
Construction & Building Technology
Ahmed Marwan, Vojtech Ernst Gall, Abdullah Alsahly, Guenther Meschke
Summary: Tunnel linings are designed to fulfill basic structural, serviceability and durability requirements permanently. In this study, a technique for modeling the segment-wise installation of tunnel linings in a 3D tunnel advance simulation is proposed to better predict time-dependent structural forces. The explicit modeling of segmental lining joints within a 3D structural model diverges significantly from conventional methods, showing the importance of accurate modeling techniques in the design process.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2021)
Article
Optics
Kangmei Li, Xingzhe He, Le Li, Liuyong Yang, Jun Hu
Summary: This study investigates the effect of laser peening on the residual stress distribution in the welding zone of aluminium-lithium alloy. The optimal combination of laser peening parameters is determined through numerical simulation and experimental verification.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Engineering, Chemical
Jose L. T. A. Pereira, Raul D. S. G. Campilho, Francisco J. G. Silva, Isidro J. Sanchez-Arce, Chander Prakash, Dharam Buddhi
Summary: This article discusses the problem of separation between sprues and terminals on a production line, and the improvement of the production process through measures such as improving molds, mold structures, and auxiliary equipment. The research results show that these interventions effectively reduce the quality of sprues and improve the operational efficiency of the production line.
Article
Thermodynamics
Riccardo Pelaccia, Paolo E. Santangelo
Summary: Extrusion of aluminum alloys is widely used to manufacture various products, but heat generated during the process can cause defects and reduce tool life. Effective die cooling is crucial for high product quality and production rate. This research explored the homogeneous-flow approach to consider both the liquid and gas phases, successfully capturing the physics and quantitatively assessing the cooling effect.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Automation & Control Systems
Chao Chen, Yawen Ouyang, Denglin Qin
Summary: In recent years, with the increasing requirements for environmental protection, energy conservation, and emission reduction, the study of lightweight structures has become more detailed. The use of lightweight materials manufactured parts is the main measure to achieve automobile lightweight. A new technology called flat-rivet clinching process (FRCP) has been developed to connect these lightweight materials. The study found that friction coefficient and material characteristics have a significant impact on material flow during the flat-rivet clinching process.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Wei Zhao, Yuting Liu, Xiandong Liu, Yingchun Shan, Xiaojun Hu
Summary: This study examines the impact of tire acoustic cavity resonance on vehicle interior noise, analyzes the influence of wheel design on vibration energy transmission characteristics, and constructs finite element models to verify modal properties through experimental tests. A sound pressure load model for the rim arising from tire acoustic cavity resonance is introduced. The power flow method is used to investigate resonance energy distribution and transmission characteristics, as well as analyzing structure intensity distribution, energy transmission efficiency, material structure damping, and the number of wheel spokes on energy transmission.
APPLIED SCIENCES-BASEL
(2021)
Article
Physics, Fluids & Plasmas
Erwan Liberge, Claudine Beghein
Summary: In this paper, a lattice Boltzmann method (LBM) is proposed for the fluid-structure interaction of an incompressible neoHookean medium. By simultaneously modeling the fluid and solid domains, the need for two separate solvers is eliminated. The LBM approach is derived from a macroscopic multiphase formulation and extends the method to the solid domain by modifying the equilibrium function. The proposed method successfully models the interaction between a fluid and a structure composed of an incompressible neoHookean medium with a single solver for both domains.
Article
Energy & Fuels
Dominika Babicka Fialova, Zdenek Jegla
Summary: Modern process and power technologies require compact and efficient equipment for transferring large heat fluxes, leading to the design of dense parallel flow systems. Accurate identification of heat flux distribution and flow uniformity is vital to avoid operating issues in complex equipment. A composite modelling system is being developed for accurate design of complex heat transfer equipment.
Article
Engineering, Chemical
Marek Pernica, Tomas Letal, Pavel Losak, Martin Nad, Marcus Reppich, Zdenek Jegla
Summary: This article mainly focuses on calculating transient thermal stress on a safety horizontal shell and tube condenser, and describing detailed calculations of transient temperature field on the shell and tubes, as well as longitudinal thermal stresses during the start-up process using finite element method analysis. Transient analyses are useful for more accurate EN 13445 calculation and fatigue calculation.
CHEMIE INGENIEUR TECHNIK
(2021)
Article
Engineering, Chemical
Marcus Reppich, Zdenek Jegla, Jakob Grondinger, Yaovi Ouezou Azouma, Vojtech Turek
Summary: The study found that the power function model provides the best fit for all fruit and vegetable samples during drying, and different technologies can be combined to ensure the required moisture content of agricultural products is reached. In a specific Togolese processing plant case, it was demonstrated that fossil fuel consumption can be decreased by 33% under favorable conditions.
CHEMIE INGENIEUR TECHNIK
(2021)
Article
Energy & Fuels
Igor Hudak, Pavel Skryja, Jiri Bojanovsky, Zdenek Jegla, Martin Krnavek
Summary: This study examines the effects of inert compounds on different process burners and finds that under certain conditions, inert gases can decrease NOx emissions and increase heat flux. However, their impact on flame patterns and temperature fields remains uncertain.
Article
Energy & Fuels
Pavel Skryja, Igor Hudak, Jiri Bojanovsky, Zdenek Jegla, Lubomir Korcek
Summary: The present study experimentally investigates and compares the characteristics of three oxygen-enhanced combustion methods. It is found that the air-oxy/fuel combustion and oxygen lancing methods have lower nitrogen oxide emissions and better performance. With increasing oxygen concentration, radiative heat transfer increases and the available heat is higher, but flue gas temperature decreases.
Article
Green & Sustainable Science & Technology
Ondrej Putna, Martin Pavlas, Vojtech Turek, Yee Van Fan
Summary: This study presents a method to directly quantify the impact of waste-to-energy plant integration on the health burden of the surrounding population. Real-world data shows that the pollutant load can be significantly reduced in the calculation scenario.
CLEAN TECHNOLOGIES AND ENVIRONMENTAL POLICY
(2022)
Article
Engineering, Chemical
Vojtech Turek, Zdenek Jegla, Miloslav Dohnal, Marcus Reppich
Summary: This is the second part of a two-part paper that focuses on assessing the accuracy of turbulence-related data from CFD simulations using effective numerical dissipation rate and effective numerical viscosity. In this part, the relevant solution data obtained through CFD are compared to values from laser Doppler anemometry measurements to explore the feasibility of assessing the accuracy of such data using the two mentioned quantities.
CHEMIE INGENIEUR TECHNIK
(2023)
Article
Engineering, Chemical
Vojtech Turek, Zdenek Jegla, Miloslav Dohnal, Marcus Reppich
Summary: This paper is the first part of a two-part series, focusing on the assessment of accuracy of turbulence-related data from computational fluid dynamics (CFD) simulations using effective numerical dissipation rate and effective numerical viscosity. The setup of CFD cases replicating a swirling pipe flow experiment from literature, where turbulence-related data measured via laser Doppler anemometry (LDA) had been reported, is presented. The method of obtaining effective numerical dissipation rate and effective numerical viscosity for each mesh cell is also discussed. The results of the study will be presented in the second part of this series.
CHEMIE INGENIEUR TECHNIK
(2023)
Article
Engineering, Multidisciplinary
Tomas Letal
Summary: Design and evaluation of bolted flange connections increasingly require tightness estimates. This paper proposes a method to estimate the leak rate based on gasket contact pressure history and utilizes an assumption to narrow down the expected leak rate interval, resulting in more accurate estimates.
INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING
(2022)
Article
Agricultural Engineering
Miroslav Rebej, Tomas Jurena, Jiri Vondal, David Fuente Herraiz, Jan Cerveny, Zdenek Jegla
Summary: This paper presents the use of PIV technique to measure velocity fields in a stirred photobioreactor and validate a CFD model. The study includes grid independence analysis, velocity profiles, and shear stresses for different operating conditions. The results show good correlation between the numerical model and experimental data, but uncertainties exist in PIV measurements for bubbly flows.
BIOSYSTEMS ENGINEERING
(2023)
Article
Energy & Fuels
Marek Vondra, Jiri Buzik, David Hornak, Michaela Prochazkova, Vaclav Miklas, Michal Tous, Zdenek Jegla, Vitezslav Masa
Summary: Reducing energy costs in Europe is challenging due to price increases. Local renewable energy sources, such as heat from hot springs, can contribute to this effort. This study aims to find a suitable cooling technology for spa resorts by testing a vacuum cooler and a plate heat exchanger. The vacuum cooler demonstrated greater robustness and resistance to fouling.