scholarly journals Calculation and Analysis of DC Magnetic Bias Current of Urban Main Transformer under the Action of Stray Current

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Weili Wu ◽  
Wenmei Chen ◽  
Lei Li
Keyword(s):  
Urban Area ◽  
Three Dimensional ◽  
Geoelectric Field ◽  
Ansys Software ◽  
Magnetic Bias ◽  
Current Field ◽  
Stray Current ◽  
Galerkin Finite Element ◽  
Dc Bias ◽  
The Mathematical Model

The stray current generated by subway running into the ground makes the main transformer in the urban area in a direct current (DC) bias state. First, the mathematical model of the metro stray current field is established and the Galerkin finite element method is applied to calculate the model. Then, the dynamic model of the stray current-induced geoelectric field under different working conditions is established by using ANSYS software, and the three-dimensional numerical simulation study of the stray current-induced geoelectric field of the subway is carried out. Finally, taking the Urumqi subway in Xinjiang as an example, the stray current-induced geoelectric field is calculated and simulated, and the correctness of the model is verified by comparing with the measured data of DC magnetic bias in the urban substation. The research can provide useful reference for the calculation and treatment of DC bias of the main transformer in the urban area under the action of stray current.

scholarly journals Accelerated Time and High-Resolution 3D Modeling of the Flow and Dispersion of Noxious Substances over a Gigantic Urban Area—The EMERGENCIES Project

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 640
Author(s):  
Olivier Oldrini ◽  
Patrick Armand ◽  
Christophe Duchenne ◽  
Sylvie Perdriel ◽  
Maxime Nibart
Keyword(s):  
High Resolution ◽  
Urban Area ◽  
3D Modeling ◽  
Three Dimensional ◽  
Hazardous Materials ◽  
Support Tool ◽  
On Demand ◽  
Simulation Domain ◽  
Dimensional Simulation ◽  
Atmospheric Release

Accidental or malicious releases in the atmosphere are more likely to occur in built-up areas, where flow and dispersion are complex. The EMERGENCIES project aims to demonstrate the operational feasibility of three-dimensional simulation as a support tool for emergency teams and first responders. The simulation domain covers a gigantic urban area around Paris, France, and uses high-resolution metric grids. It relies on the PMSS modeling system to model the flow and dispersion over this gigantic domain and on the Code_Saturne model to simulate both the close vicinity and the inside of several buildings of interest. The accelerated time is achieved through the parallel algorithms of the models. Calculations rely on a two-step approach: the flow is computed in advance using meteorological forecasts, and then on-demand release scenarios are performed. Results obtained with actual meteorological mesoscale data and realistic releases occurring both inside and outside of buildings are presented and discussed. They prove the feasibility of operational use by emergency teams in cases of atmospheric release of hazardous materials.

Research on cargo-loading optimization based on genetic and fuzzy integration

2021 ◽  
Vol 40 (4) ◽  
pp. 8493-8500
Author(s):  
Yanwei Du ◽  
Feng Chen ◽  
Xiaoyi Fan ◽  
Lei Zhang ◽  
Henggang Liang
Keyword(s):  
Genetic Algorithm ◽  
Mathematical Model ◽  
Three Dimensional ◽  
Distribution Center ◽  
Long Time ◽  
Low Efficiency ◽  
Decision Making Model ◽  
The Mathematical Model ◽  
Loading Scheme

With the increase of the number of loaded goods, the number of optional loading schemes will increase exponentially. It is a long time and low efficiency to determine the loading scheme with experience. Genetic algorithm is a search heuristic algorithm used to solve optimization in the field of computer science artificial intelligence. Genetic algorithm can effectively select the optimal loading scheme but unable to utilize weight and volume capacity of cargo and truck. In this paper, we propose hybrid Genetic and fuzzy logic based cargo-loading decision making model that focus on achieving maximum profit with maximum utilization of weight and volume capacity of cargo and truck. In this paper, first of all, the components of the problem of goods stowage in the distribution center are analyzed systematically, which lays the foundation for the reasonable classification of the problem of goods stowage and the establishment of the mathematical model of the problem of goods stowage. Secondly, the paper abstracts and defines the problem of goods loading in distribution center, establishes the mathematical model for the optimization of single car three-dimensional goods loading, and designs the genetic algorithm for solving the model. Finally, Matlab is used to solve the optimization model of cargo loading, and the good performance of the algorithm is verified by an example. From the performance evaluation analysis, proposed the hybrid system achieve better outcomes than the standard SA model, GA method, and TS strategy.

Magneto convective flow of casson nanofluid due to Stefan blowing in the presence of bio-active mixers

2021 ◽  
pp. 239779142110166
Author(s):  
Venkatesh Puneeth ◽  
Sarpabhushana Manjunatha ◽  
Bijjanal Jayanna Gireesha ◽  
Rama Subba Reddy Gorla
Keyword(s):  
Magnetic Field ◽  
Brownian Motion ◽  
Convective Flow ◽  
Three Dimensional ◽  
Induced Magnetic Field ◽  
Density Profiles ◽  
Casson Nanofluid ◽  
And Brownian Motion ◽  
Similarity Transformations ◽  
The Mathematical Model

The induced magnetic field for three-dimensional bio-convective flow of Casson nanofluid containing gyrotactic microorganisms along a vertical stretching sheet is investigated. The movement of these microorganisms cause bioconvection and they act as bio-active mixers that help in stabilising the nanoparticles in the suspension. The two forces, Thermophoresis and Brownian motion are incorporated in the Mathematical model along with Stefan blowing. The resulting model is transformed to ordinary differential equations using similarity transformations and are solved using [Formula: see text] method. The Velocity, Induced Magnetic field, Temperature, Concentration of Nanoparticles, and Motile density profiles are interpreted graphically. It is observed that the Casson parameter decreases the flow velocity and enhances the temperature, concentration, and motile density profiles and also it is noticed that the blowing enhances the nanofluid profiles whereas, suction diminishes the nanofluid profiles. On the other hand, it is perceived that the rate of heat conduction is enhanced with Thermophoresis and Brownian motion.

scholarly journals The Influence of PZT Actuators Positioning in Active Structural Acoustic Control

10.14311/968 ◽  
2007 ◽  
Vol 47 (4-5) ◽  
Author(s):  
P. Švec ◽  
V. Jandák
Keyword(s):  
Sound Field ◽  
Structural Vibration ◽  
Structural Acoustics ◽  
The Finite Element Method ◽  
Ansys Software ◽  
Structural Vibrations ◽  
Radiated Power ◽  
Acoustic Control ◽  
Radiated Sound ◽  
The Mathematical Model

This paper deals with the effect of secondary actuator positioning in an active structural acoustics control (ASAC) experiment. The ASAC approach is based on minimizing the sound radiation from structures to the far field by controlling the structural vibrations. In this article a rectangular steel plate structure was assumed with one secondary actuator attached to it. As a secondary actuator, a specially designed piezoelectric stripe actuator was used. We studied the effect of the position of the actuator on the pattern and on the radiated sound field of the structural vibration, with and without active control. The total radiated power was also measured. The experimental data was confronted with the results obtained by a numerical solution of the mathematical model used. For the solution, the finite element method in the ANSYS software package was used. 

Simulation Investigation on Environment-Induced Pitting Corrosion on the Metal Surface

2021 ◽  
Vol 13 (5) ◽  
pp. 820-828
Author(s):  
Wei Zhang ◽  
Shengli Lv ◽  
Leijiang Yao ◽  
Xiaoyan Tong
Keyword(s):  
Mathematical Model ◽  
Pitting Corrosion ◽  
Three Dimensional ◽  
Corrosion Damage ◽  
Sudden Onset ◽  
Ion Concentration ◽  
Two Dimensional Image ◽  
Aging Aircraft ◽  
Efficient Calculation ◽  
The Mathematical Model

The prediction of corrosion damage is one of effective research methods in the safety inspection of aging aircraft structures. A mathematical model for quantifying corrosion damage is used in this paper to predict the onset of corrosion on structural surfaces exposed to aggressive environments. Based on the finite difference technique, the evolution process of local pitting corrosion on the surface of aluminum alloy in the medium is simulated, which can consider the sudden onset and the randomness of pitting corrosion. The effect of local ion concentration and oxide film damage on subsequent pitting nucleation was analyzed. Based on the efficient calculation program, the effectiveness of the mathematical model is verified by the comparison between the corrosion damage morphology and the experimental data in the literature. The results show a more widespread distribution of subsequent pits because of stronger aggressive ions are released during the life cycle of active pits and the higher diffusion coefficient of the aggressive ions. The three dimensional morphology is generated by image processing method based on the gray value of the two dimensional image of pits.

Performance calculation of electrothermal anti-icing system on three-dimensional surface

2020 ◽  
Vol 34 (14n16) ◽  
pp. 2040106
Author(s):  
Zheng-Zhi Wang ◽  
Chong-Yang Liu ◽  
Chun-Ling Zhu ◽  
Ning Zhao
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer Coefficient ◽  
Three Dimensional ◽  
Leading Edge ◽  
Mass Transfer Process ◽  
Protection Systems ◽  
The Mathematical Model ◽  
Performance Calculation ◽  
Dimensional Surface ◽  
Good Agreement

The electrothermal anti-icing system is one of the commonly used ice protection systems. In this paper, the heat and mass transfer process on three-dimensional surface of the electrothermal anti-icing system is analyzed. The mass and energy conservation equations are given. A calculation method of the convective heat transfer coefficient on three-dimensional surface is proposed, and the mathematical model of the electrothermal anti-icing system is established. The model is applied to calculate the temperature distribution of the anti-icing system in different conditions. The numerical results are compared with experimental data, and the good agreement between them proves that the developed method is reliable. The results also show that only part of droplets impacted on the leading edge evaporate immediately, while the rest of droplets move downstream in the form of liquid water and evaporate gradually.

scholarly journals An Integrated Front-end Circuit Board for Air-Coupled CMUT Burst-Echo Imaging

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6128
Author(s):  
Lei Ye ◽  
Jian Li ◽  
Hui Zhang ◽  
Dongmei Liang ◽  
Zhuochen Wang
Keyword(s):  
Imaging System ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Ultrasonic Transducers ◽  
Circuit Board ◽  
Capacitive Micromachined Ultrasonic Transducers ◽  
Front End ◽  
Field Programmable ◽  
Good Potential ◽  
Dc Bias

To conduct burst-echo imaging with air-coupled capacitive micromachined ultrasonic transducers (CMUTs) using the same elements in transmission and reception, this work proposes a dedicated and integrated front-end circuit board design to build an imaging system. To the best of the authors’ knowledge, this is the first air-coupled CMUT burst-echo imaging using the same elements in transmission and reception. The reported front-end circuit board, controlled by field programmable gate array (FPGA), consisted of four parts: an on-board pulser, a bias-tee, a T/R switch and an amplifier. Working with our 217 kHz 16-element air-coupled CMUT array under 100 V DC bias, the front-end circuit board and imaging system could achieve 22.94 dB signal-to-noise ratio (SNR) in burst-echo imaging in air, which could represent the surface morphology and the three-dimensional form factor of the target. In addition, the burst-echo imaging range of our air-coupled CMUT imaging system, which could work between 52 and 273 mm, was discussed. This work suggests good potential for ultrasound imaging and gesture recognition applications.

Three-Dimensional Strain-Based Model for the Severity Characterization of Dented Pipelines

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
Chike Okoloekwe ◽  
Muntaseer Kainat ◽  
Doug Langer ◽  
Sherif Hassanien ◽  
J.J. Roger Cheng ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Numerical Models ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Computation Time ◽  
Order Continuity ◽  
Element Analysis ◽  
The Mathematical Model ◽  
Derivatives Of

Oil and gas pipelines traverse long distances and are often subjected to mechanical forces that result in permanent distortion of its geometric cross section in the form of dents. In order to prioritize the repair of dents in pipelines, dents need to be ranked in order of severity. Numerical modeling via finite element analysis (FEA) to rank the dents based on the accumulated localized strain is one approach that is considered to be computationally demanding. In order to reduce the computation time with minimal effect to the completeness of the strain analysis, an approach to the analytical evaluation of strains in dented pipes based on the geometry of the deformed pipe is presented in this study. This procedure employs the use of B-spline functions, which are equipped with second-order continuity to generate displacement functions, which define the surface of the dent. The strains associated with the deformation can be determined by evaluating the derivatives of the displacement functions. The proposed technique will allow pipeline operators to rapidly determine the severity of a dent with flexibility in the choice of strain measure. The strain distribution predicted using the mathematical model proposed is benchmarked against the strains predicted by nonlinear FEA. A good correlation is observed in the strain contours predicted by the analytical and numerical models in terms of magnitude and location. A direct implication of the observed agreement is the possibility of performing concise strain analysis on dented pipes with algorithms relatively easy to implement and not as computationally demanding as FEA.

Wave-Current Loading on a Vertical Slender Cylinder by Two Different Numerical Models

2006 ◽  
Author(s):  
M. H. Zaman ◽  
R. E. Baddour
Keyword(s):  
Numerical Models ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Vertical Cylinder ◽  
Finite Depth ◽  
Offshore Structure ◽  
Current Field ◽  
Oblique Wave ◽  
Waves And Currents ◽  
Current Loading

The study of the effects resulting from the interaction of a combined wave-current field with any ocean structure is important for the design and performance evaluation of that structure. The prudent computation of forces exerted by waves and currents is an essential task in the study of the stability of an offshore structure. A study on the loading of an oblique wave and a current field on a fixed vertical slender cylinder in a 3D flow frame is illustrated in Zaman and Baddour (2004). The three dimensional expressions describing the characteristics of the combined wave-current field in terms of mass, momentum and energy flux conservation equations are formulated. The parameters before the interaction of the oblique wave-free uniform current and current-free wave are used to formulate the kinematics of the flow field. These expressions are also employed to formulate and calculate the loads imparted by the wave-current fluid flow on a bottom mounted slender vertical cylinder. In this work a 2D version of the above 3D model called here Model-I has been used for the numerical computations presented in this paper. The second model denoted model-II in the present paper is based on Euler equations. This model is formulated through the vertical integration of the continuity equation and the equations of motions, Zaman et al (1997). A semi-implicit numerical technique is employed for the numerical solution. In the present paper comparisons are made between the results obtained from the 2D version of the above models in finite depth. Both models are then compared with some relevant experimental data. Morison et al equation (1950) is deployed for the load computations in all cases.

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