scholarly journals Development of oxidation heat of the coal left in the mined-out area of a longwall face: Modelling using the fluent software

2008 ◽  
Vol 44 (1) ◽  
pp. 73-81 ◽  
Author(s):  
B. Taraba ◽  
V. Slovak ◽  
Z. Michalec ◽  
J. Chura ◽  
A. Taufer
Keyword(s):  
Bituminous Coal ◽  
Three Dimensional ◽  
Longwall Face ◽  
Heating Process ◽  
Three Dimensional Model ◽  
Main Attention ◽  
Fluent Software ◽  
Laboratory Investigations ◽  
Gob Area

A commercial CFD software program, Fluent, was used to study oxidation processes in the longwall mined-out (gob) area. A three-dimensional model of the gob area with an advancing coal face has been developed. For the model, typical oxidation behavior of a bituminous coal from the Ostrava-Karvin? District was incorporated as resulted from laboratory investigations. The longwall gob area was designed on the basis of the actual longwall face district. Detailed measurements in the district then enabled re-verification of the model outputs with actual data in situ. The main attention was paid to modelling the effect of grain size of the coal left in the mined-out area on the oxidation heat and gases evolution. Numerical simulations confirmed the existence of an 'optimal' zone for intense development of the spontaneous heating process in the gob area.

scholarly journals Ballast bed resistance characteristics based on discrete-element modeling

2018 ◽  
Vol 10 (6) ◽  
pp. 168781401878146 ◽  
Author(s):  
Zhiping Zeng ◽  
Shanyi Song ◽  
Weidong Wang ◽  
Haijian Yan ◽  
Guoshu Wang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Discrete Element ◽  
Discrete Element Modeling ◽  
Slope Gradient ◽  
Three Dimensional Model ◽  
Lateral Resistance ◽  
In Situ Experiments ◽  
Distribution Limits ◽  
Longitudinal Resistance

In this study, in situ experiments were conducted to study the changing characteristics of the lateral and longitudinal resistance of a ballast bed, and a three-dimensional model for the ballast bed and sleeper was constructed based on the discrete-element method. The effects of the lateral and longitudinal resistance of the ballast bed, such as gravel ballast grading, sleeper depth, the angle of the shoulder slope, and ballast bed shoulder width, among others, were studied. The results suggest that (1) the lateral and longitudinal resistance of the ballast bed increases with the widening of ballast grading, and within the size distribution limits, the resistance of the ballast bed satisfies the specification; (2) the lateral and longitudinal resistance of ballast bed increases with an increase in the sleeper depth and the resistance of ballast bed satisfies the specifications for sleeper depth greater than 150 mm; (3) the lateral resistance of the ballast bed increases with a decrease in the angle of the shoulder slope, whereas the longitudinal resistance remains unchanged and the resistance of the ballast bed satisfies the specifications for slope gradient of 1:1.75 or less; and finally, (4) the lateral resistance of the ballast bed increases with the widening of the ballast bed shoulder, whereas the longitudinal resistance remains unchanged, and the resistance of ballast bed satisfies the specifications when the shoulder width is greater than 400 mm.

scholarly journals Hydraulic modeling of combined sewers overflow integrating the results of the SWMM and CFX models.

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
D. Pulgarín ◽  
J. Plaza ◽  
J. Ruge ◽  
J. Rojas
Keyword(s):  
Three Dimensional ◽  
Hydraulic Modeling ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
One Dimensional ◽  
Ansys Cfx ◽  
Combined Sewer ◽  
The One ◽  
Swmm Model

This study proposes a methodology for the calibration of combined sewer overflow (CSO), incorporating the results of the three-dimensional ANSYS CFX model in the SWMM one-dimensional model. The procedure consists of constructing calibration curves in ANSYS CFX that relate the input flow to the CSO with the overflow, to then incorporate them into the SWMM model. The results obtained show that the behavior of the flow over the crest of the overflow weir varies in space and time. Therefore, the flow of entry to the CSO and the flow of excesses maintain a non-linear relationship, contrary to the results obtained in the one-dimensional model. However, the uncertainty associated with the idealization of flow methodologies in one dimension is reduced under the SWMM model with kinematic wave conditions and simulating CSO from curves obtained in ANSYS CFX. The result obtained facilitates the calibration of combined sewer networks for permanent or non-permanent flow conditions, by means of the construction of curves in a three-dimensional model, especially when the information collected in situ is limited.

scholarly journals Three-dimensional model of bone marrow

Blood ◽  
1978 ◽  
Vol 51 (4) ◽  
pp. 633-643 ◽  
Author(s):  
N Mohandas ◽  
M Prenant
Keyword(s):  
Bone Marrow ◽  
Close Association ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Scale Models ◽  
Marrow Space ◽  
Normal Rat

Abstract Three-dimensional scale models of bone marrow from a hypertransfused and a normal rat were constructed. The model of marrow from the hypertransfused rat demonstrated the existence of distinct erythroblastic islands in situ in which the erythroblasts underwent sychronous maturation. Macrophages were found in close association with the developing erythroblasts. The immature erythroblasts were tightly grouped, but as they matured they began to move apart. Erythroblasts in individual clusters were found to be at the same stage of morphologic maturation. In contrast, the model of marrow from the normal rat showed a majority of clusters containing erythroblasts at various stages of maturation. Erythropoiesis was not spatially restricted to the area proximal to the sinuses but was found to occur over the entire marrow space. Thrombopoiesis, however, was found to take place exclusively in the immediate vicinity of the marrow sinuses.

Crystallographic Features of the A-Type and CE-Type Antiferromagnetic States in the Simple-Perovskite Manganite System Sr1-xNdxMnO3

2011 ◽  
Vol 409 ◽  
pp. 532-537
Author(s):  
Yusuke Onezawa ◽  
Yasuhide Inoue ◽  
Masazumi Arao ◽  
Yasumasa Koyama
Keyword(s):  
Room Temperature ◽  
Three Dimensional ◽  
Electronic System ◽  
Paramagnetic State ◽  
Heating Process ◽  
In Situ Observation ◽  
Perovskite Manganite ◽  
Transmission Electron ◽  
Highly Correlated

The electronic states of Sr1-xNdxMnO3 with the simple perovskite structure are characterized by a three-dimensional highly-correlated electronic system. To understand the detailed features of the A-and CE-type antiferromagnetic states in this system, their crystallographic features for x = 0.47, 0.48, and 0.50 have been investigated mainly by both x-ray powder diffraction and transmission electron microscopy. It was found at room temperature that the crystal structure for x = 0.47 was determined to have the monoclinic C2/m symmetry, while the orthorhombic Imma structure was confirmed for x = 0.48 and 0.50. The in-situ observation for x = 0.47 indicated that, in the heating process from room temperature, the C2/m-to-Imma transition occurred in the paramagnetic state, and that the A-type antiferromagnetic state appeared below about 200 K on cooling. In addition, the cooling from room temperature for x = 0.48 and 0.50 resulted in the direct transitions from the orthorhombic Imma state to the A-and CE-type antiferromagnetic states, respectively. Based on these features, we simply discussed the physical origin of the appearance of the paramagnetic state with the monoclinic symmetry for x = 0.47.

scholarly journals Study on Temporal and Spatial Characteristics of Overlying Strata in Deep Coal Mining Process

2021 ◽  
Author(s):  
Bang-an Zhang ◽  
Yang yushun ◽  
Dong-ming Zhang
Keyword(s):  
Stress Concentration ◽  
Coal Seam ◽  
Coal Mining ◽  
Three Dimensional ◽  
In Situ Stress ◽  
Three Dimensional Model ◽  
Concentration Coefficient ◽  
Working Face ◽  
Stress Concentration Coefficient

Abstract This paper adopts the stress relief method to test the in-situ stress in the field to obtain the in-situ stress distribution characteristics of No. 2+3# coal seam. A three-dimensional model was established with the No. S3012 working face as the engineering background, and the measured in-situ stress values ​​were applied to the three-dimensional model, and the spatial-temporal evolution characteristics of coal and rock mass around the stope during coal seam mining were studied. The specific conclusions are as follows: the three-dimensional stress distribution map in front of, behind and on both sides of the working face in the process of coal mining are obtained. As the working face goes on, the maximum value of the supporting stress formed in front of, behind and on both sides of the working face shifts to the corner, presenting a “hump-like” distribution. The stress concentration coefficient of front, back and both sides of stope increases linearly with the increase of mining size. Under the same mining size, the stress concentration coefficient in front of stope is the smallest, and the stress concentration coefficient on both sides is the largest. The three-dimensional displacement field distribution nephogram of overlying strata in the process of coal mining is obtained. With the continuous advance of the working face, the roof strata of coal seam undergo continuous dynamic subsidence process, and the roof subsidence increases continuously, showing the shape of "bowl" with sharp bottom. In the process of working face mining, the roof displacement of coal seam showed an "O" shape evolution characteristic. The three-dimensional distribution cloud map of the plastic zone of coal and rock mass in the process of working face mining was obtained, and the failure volume of the plastic zone gradually increases with the continuous progress of the working face.

scholarly journals THEORETICAL BASIS OF DESIGN STRUCTURE OF THE DIGITAL EDUCATIONAL ENVIRONMENT

2020 ◽  
pp. 249-257
Author(s):  
Игорь Давыдович Лельчицкий ◽  
Ален Павлович Сильченко ◽  
Светлана Юрьевна Щербакова
Keyword(s):  
Theoretical Basis ◽  
Three Dimensional ◽  
Educational Environment ◽  
Educational Process ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Main Attention ◽  
Teacher Student ◽  
Design Structure ◽  
Level Of Training

Теоретической основой проектирования цифровой образовательной среды является трехмерная модель, предпосылкой для разработки которой стала технологическая карта изучаемого предмета (В.М. Монахов). Основное внимание при разработке модели сосредоточено на логике взаимодействия триады «учитель - ученик - технология». Структурно проектируемая цифровая образовательная среда включает в себя три основных информационных блока: учебный процесс изучаемого предмета; уровень освоения учебного содержания (выбор обучающимся уровня обучения по изучаемому предмету; универсальные учебные действия, контент, состоящий из учебных ситуаций. The theoretical basis for the design of a digital educational environment is a three-dimensional model, a prerequisite for the development of which was the technological map of the studied subject (V.M. Monakhov). The main attention in the development of the model is focused on the logic of the interaction of the triad «teacher - student - technology». The structurally designed digital educational environment includes three main information blocks: the educational process of the studied subject; the level of mastering the educational content (the choice by the student of the level of training in the studied subject; universal educational actions, content consisting of educational situations.

scholarly journals NUMERICAL RESEARCH OF THE MOISTURE CONDENSATION ELIMINATION IN THE CABIN OF THE UNIFIED TECHNOLOGICAL ELECTRIC TRANSPORT VEHICLE

2018 ◽  
Vol 15 (4) ◽  
pp. 538-546
Author(s):  
N. M. Filkin ◽  
A. M. Tatarkin
Keyword(s):  
Three Dimensional ◽  
Electric Transport ◽  
Three Dimensional Model ◽  
Ansys Fluent ◽  
Air Ventilation ◽  
Fluent Software ◽  
Moisture Condensation ◽  
Transport Vehicle ◽  
Numerical Research ◽  
Forced Air

Introduction. This article deals with the problem of moisture condensation inside the cabin of the technological electric transport vehicle. The hypothesis of using the forced air ventilation in the cabin is substantiated, by which such problem could be solved.Materials and methods. The article describes the application of the ANSYS Fluent Software Package to assess the effect of the location and shape of the ducts on the ventilation process inside the cabin. Accordingly, the key stages of air flow modeling in this program are considered.Results. The main content of the research is to analyze the modeling airflow process in the cabins with a different configuration of inlet and outlet nozzles. Therefore, basing on the analysis of the obtained airflow velocity contours, the conclusion is made about the rational arrangement of the inlet and outlet channels.Discussion and conclusions. The conclusion is made about the necessity of the further research that would refer to creating a three-dimensional model of the cabin. The results of the research as well as resolutions are taken into account.

scholarly journals Modeling of Eddy Current Welding of Rail: Three-Dimensional Simulation

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 947 ◽  
Author(s):  
Xiankun Sun ◽  
He Liu ◽  
Wanqing Song ◽  
Francesco Villecco
Keyword(s):  
Numerical Simulation ◽  
Heat Treatment ◽  
Eddy Current ◽  
Magnetic Induction ◽  
Three Dimensional ◽  
Heating Process ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Weak Formulation

In this paper is given a three-dimensional numerical simulation of the eddy current welding of rails where the longitudinal two directions are not ignored. In fact, usually it is considered a model where, in the two-dimensional numerical simulation of rail heat treatment, the longitudinal directions are ignored for the magnetic induction strength and temperature, and only the axial calculation is performed. Therefore, we propose the electromagnetic-thermal coupled three-dimensional model of eddy current welding. The induced eddy current heat is obtained by adding the z-axis spatial angle to the two-dimensional electromagnetic-thermal, thus obtaining some new results by coupling the numerical simulation and computations of the electric field and magnetic induction intensity of the three-dimensional model. Moreover, we have considered the objective function into a weak formulation. The three-dimensional model is then meshed by the finite element method. The electromagnetic-thermal coupling has been numerically computed, and the parametric dependence to the eddy current heating process has been fully studied. Through the numerical simulation with different current densities, frequencies, and distances, the most suitable heat treatment process of U75V rail is obtained.

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