scholarly journals The Influence of Ventilation Arrangement on the Mechanism of Dust Distribution in Woxi Pithead

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Zhiyong Zhou ◽  
Pei Hu ◽  
Chongchong Qi ◽  
Tianpei Niu ◽  
Ming Li ◽  
...  
Keyword(s):  
Numerical Study ◽  
Numerical Models ◽  
Ventilation System ◽  
Three Dimensional ◽  
Sensitivity Study ◽  
Concentration Data ◽  
Two Phase ◽  
Air Volume ◽  
Working Face ◽  
Dust Distribution

Suppressing and removing mine dust from the working face is an important task for underground mines worldwide. In this paper, a numerical study was carried out to investigate the influence of ventilation arrangement on the mechanism of dust distribution. The Woxi Pithead of Hunan Chenzhou Mining Co., Ltd, China, was used as a case study, which adopted a widely used far-pressing-near-absorption (FPNA) ventilation system. Based on the theory of gas-solid two-phase flow, the program ANSYS Fluent was utilized, and the three-dimensional airflow migration and dust diffusion numerical models were simulated. The established computational fluid dynamics (CFD) models were validated using the airflow velocity data and the dust concentration data monitored at different positions from the operating coal mine. A comprehensive sensitivity study was conducted to investigate the influence of four parameters on dust suppression, including the distance of pressure air duct outlet from working face (Lp-outlet), the distance of exhaust air duct inlet from working face (Le-inlet), the ratio of pressing air volume to lab sorption air volume (K), and the installation height of the air duct (H). The optimum ventilation layout parameters were obtained through the simulation of the wind field and dust behaviour. The results show that there were four regions during the airflow field, namely, the jet zone, the recirculation zone, the vortex zone, and the mixing zone of pressure and exhaust airflow. All four parameters were found to have an important influence on the mass concentration of dust, and the optimum ventilation layout parameters were determined to be Lp-outlet = 18 m, Le-inlet = 3 m, K = 1.2, and H = 1.6 m.

Wall-Attachment Fan Drum Enclosed Dust Removal Theory and Technology of Mechanized Working Face

2013 ◽  
Vol 807-809 ◽  
pp. 653-662
Author(s):  
Wei Min Cheng ◽  
Yun Wang ◽  
Gang Zhou ◽  
Hao Wang
Keyword(s):  
Ventilation System ◽  
Simple Algorithm ◽  
Field Application ◽  
Dust Removal ◽  
Distribution Law ◽  
Two Phase ◽  
Suppression Effect ◽  
Working Face ◽  
Dust Distribution ◽  
Removal System

FLUENT software and SIMPLE algorithm which was based on parity grid was used to carry out the numerical simulation of spraying dust gas-particle two-phase flow field of the mechanized working face with a single pressure pumping hybrid ventilation system. The dust distribution law of the mechanized working face was mastered and the main dust prevention area was determined to be the middle of the roadway and wall-attachment fan drum enclosed dust removal system of mechanized working face was also planned to be established according to the simulation result. It had been proved that fully-mechanized coal winning machine enclosed dust removal system had a large advantage in reducing dust by computer simulation and field application, the dust suppression effect was remarkable.

Numerical study of flow pattern around lateral intake in a curved channel

2019 ◽  
Vol 30 (11) ◽  
pp. 1950083 ◽  
Author(s):  
Hossien Montaseri ◽  
Hossein Asiaei ◽  
Abdolhossein Baghlani ◽  
Pourya Omidvar
Keyword(s):  
Experimental Data ◽  
Numerical Model ◽  
Flow Pattern ◽  
Numerical Study ◽  
Numerical Models ◽  
Three Dimensional ◽  
Curved Channel ◽  
Channel Bend ◽  
Outer Bank ◽  
Center Region

This paper deals with numerical study of flow field in a channel bend in presence of a lateral intake using three-dimensional numerical model SSIIM2. The effects of bend on the structure of the flow around the intake are investigated and compared with the experimental data. The tests are carried out in a U-shaped channel bend with a lateral intake. The intake is located at the outer bank of an 180∘ bend at position 115∘ with 45∘ diversion angle and the experimental data can be used to calibrate and validate numerical models. The results show that both the center-region and outer-bank cross-stream circulations are observed in the experiments while only the former is captured by the numerical model due to the limitations of the turbulence model. In the curved channel after the intake, both experimental and numerical results show another type of bi-cellular circulations in which clockwise center-region circulations and counterclockwise circulations near the inner bank and the free surface (inner-bank circulations) are captured. The study shows that the numerical model very satisfactorily predicts streamlines, velocity field and flow pattern in the channel and in vicinity of the intake. Investigation of flow pattern around lateral intake in channel bends shows that contrary to the case of flow diversion in straight channels, the width of the dividing stream surface near water surface level is greater than that of near bed level. Finally, the effects of position and diversion angle of the lateral intake, discharge ratio and upstream Froude number on the flow pattern are investigated.

Three-dimensional numerical study on evaporating two-phase flow in heated micro T-junction

2021 ◽  
pp. 117375
Author(s):  
Zhe Yan ◽  
Haoxiang Huang ◽  
Shanshan Li ◽  
Wei Wang ◽  
Zhenhai Pan
Keyword(s):  
Two Phase Flow ◽  
Numerical Study ◽  
Three Dimensional ◽  
Phase Flow ◽  
Two Phase

Numerical Study of the Thermosolutal Convection Induced Macrosegregation during Columnar Solidification

2010 ◽  
Vol 154-155 ◽  
pp. 1415-1418
Author(s):  
Jing Hao ◽  
Meng Huai Wu ◽  
Andreas Ludwig ◽  
Monika Grasser
Keyword(s):  
Numerical Model ◽  
Process Parameters ◽  
Thermophysical Properties ◽  
Numerical Study ◽  
Sensitivity Study ◽  
Thermosolutal Convection ◽  
Two Phase ◽  
Numerical Problem ◽  
Solidification Model ◽  
Comparison With Experiments

As a response to “call for contribution to a numerical problem for 2D columnar solidification of binary alloys” [Bellet et al., Int. J. Therm. Sci., Vol. 48(11)(2009), p. 2013], the macrosegregation in a Pb-18wt.%Sn benchmark casting is numerically studied with a two-phase columnar solidification model developed by the current authors. The studies were done with 2D calculations in response to the call, and a 3D calculation was performed to confirm the consistency with the 2D case. A grid-sensitivity study was done to ensure the reliability and accuracy of the present results. The segregation mechanism due to thermosolutal convection was analyzed and the uncertainties resulting from the inaccurate thermophysical properties, modelling and process parameters are discussed. The numerical model was evaluated by comparison with experiments.

Numerical Study of the Three-Dimensional Structure of a Bubble Plume

2000 ◽  
Vol 122 (4) ◽  
pp. 754-760 ◽  
Author(s):  
Y. Murai ◽  
Y. Matsumoto
Keyword(s):  
Numerical Study ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Lagrangian Model ◽  
Dimensional Structure ◽  
Bubble Motion ◽  
Bubble Plume ◽  
Two Phase ◽  
Simulated Flow ◽  
Good Agreement

The whole behavior and the micro scale flow characteristics of a three-dimensional bubble plume are investigated numerically. The bubble plume drives liquid convection in a tank due to strong local two-phase interaction so that the Eulerian-Lagrangian model is formulated with emphasis on the translational motions of the bubble. In this model, each bubble motion is tracked in a bubbly mixture which is treated as a continuum. The three-dimensional numerical results reveal several particular structures, such as swaying and swirling structures of the bubble plume. These simulated flow structures show qualitatively good agreement with the experimental observations. Furthermore, the detailed behavior in the bubble plume is clarified by various analysis to discuss the dominant factors causing such the strong three-dimensionality. [S0098-2202(00)00904-4]

Numerical study of droplet breakup in an asymmetric T-junction microchannel with different cross-section ratios

2021 ◽  
pp. 2250023
Author(s):  
Milad Isanejad ◽  
Keivan Fallah
Keyword(s):  
Cross Section ◽  
Numerical Study ◽  
Three Dimensional ◽  
Droplet Breakup ◽  
Width Ratio ◽  
Two Phase ◽  
Droplet Motion ◽  
Daughter Droplets ◽  
Breakup Time ◽  
Good Agreement

In this study, numerical simulations are conducted to investigate droplet breakup in an asymmetric [Formula: see text]-junction microchannel with different cross-section ratios. To this approach, a two-phase model based on the volume of fluid (VOF) method is adopted to study the three-dimensional feature of droplet motion inside [Formula: see text]-junctions. The comparison reveals that the present results are in good agreement with previous studies. The effects of the capillary number (Ca), the non-dimensional droplet length ([Formula: see text]), and the non-dimensional width ratio ([Formula: see text]) on the breakup time and splitting ratio of daughter droplets are studied. Five distinct regimes are observed involving the non-breakup, breakup with tunnel, breakup without tunnel, asymmetric breakup, and sorting. Achieved results indicate that the time of breakup ([Formula: see text]) increases about 15% when the Ca is increased from 0.0134 to 0.0268 (about 100%). It is also found that the mass center of the mother droplet in the primary channel is shifted to a larger wide branch, which facilitates the asymmetric breakup of the droplet in a [Formula: see text]-junction microchannel.

Sediment transport and bed evolution in a 180∘ curved channel with lateral intake: Numerical simulations using Eulerian and Discrete Phase models

2020 ◽  
Vol 31 (08) ◽  
pp. 2050113
Author(s):  
H. Montaseri ◽  
K. Tavakoli ◽  
S. Evangelista ◽  
P. Omidvar
Keyword(s):  
Sediment Transport ◽  
Numerical Simulations ◽  
Numerical Models ◽  
Three Dimensional ◽  
Secondary Flows ◽  
The Other ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Bed Topography ◽  
Discrete Phase

Lateral intakes are hydraulic structures used for domestic, agricultural and industrial water conveyance, characterized by a very complex three-dimensional morphodynamic behavior: since streamlines near the lateral intake are deflected, some vortices form, pressure gradient, shear and centrifugal forces at the intake generate flow separation and a secondary movement, responsible for local scour and sediment deposition. On the other side, the modeling of flows, besides the sediment transport, in curved channels implies some more complications in comparison with straight channels. In this research, this complex process has been investigated experimentally and numerically, with the mechanism of sediment transport, bed topography evolution, flow pattern and their interactions. Experiments were performed in the Laboratory of Tarbiat Modares University, Iran, where a U-shaped channel with a lateral intake was installed and dry sediment was injected at constant rate into a steady flow. Due to the spiral flow, the bed topography changes significantly and the bed forms in turn affect the sediment entering the intake. Different from the previous works on this topic which were mainly based on laboratory experiments, here, Computational Fluid Dynamics (CFD) numerical simulations with FLUENT software were also performed, specifically with the two-phase Eulerian Model (EM) and Discrete Phase Model (DPM), at the aim of evaluating their performance in reproducing the observed physical processes. This software is used for a large variety of CFD problems, but not much for simulating sediment transport phenomena and bed topography evolution. The comparison of the results obtained through the two models against the laboratory experimental data proved a good performance of both the models in reproducing the main features of the flow, for example, the longitudinal and vertical streamlines and the mechanism of particles movement. However, the EM reveals a better performance than DPM in the prediction of the secondary flows and, consequently, of the bed topography evolution, whereas the DPM well depicts the particles pattern, predicts the location of trapped particles and determines the percentage of sediment entering the intake. The numerical models so calibrated and validated were applied to other cases with different positions of the intake in the bend. The results show that mechanism of sediment entrance into the intake varies in different position. If the intake is installed in the second half of the bend, the sediment accumulates along the inner bank of the bend and enters the intake from downstream edge of intake; on the other side, if it is placed in the first half of the bend, the sediment accumulates along both the inner and the outer bends and, therefore, more sediment enters the intake. Also the results of the simulations performed with the DPM model for different positions of the lateral intake show that for all discharge ratios, the position of 120∘ is the one which guarantees the minimum ratio of sediment diverted to the intake (Gr).

scholarly journals Numerical Study of the Biomechanical Behaviour of the Different Implantation Methods of the Reverse Shoulder Replacement

2019 ◽  
Vol 43 ◽  
pp. 54-66
Author(s):  
Salah Mebarki ◽  
Benaoumeur Aour ◽  
Malachanne Etienne ◽  
Franck Jourdan ◽  
Abdel Hakem Belaghit ◽  
...  
Keyword(s):  
Numerical Study ◽  
Numerical Models ◽  
Total Shoulder Arthroplasty ◽  
Three Dimensional ◽  
Shoulder Prosthesis ◽  
Three Dimensional Model ◽  
Biomechanical Behavior ◽  
Three Dimensional Models ◽  
Reverse Shoulder Replacement ◽  
Reverse Total Shoulder

Despite the widespread use of reverse total shoulder arthroplasty, there is still a problem of conflict between the polyethylene cup of the prosthesis and the scapula, which over time causes the phenomenon of notching. In order to circumvent this problem correctly, several innovations have been proposed regard to the implementation method. In this context, the aim of this work is to study the biomechanical behavior of new implantation methods using different glenoid configurations in order to avoid the notching phenomenon between the cup and the scapula. The study was performed using virtual prototypes of the shoulder prosthesis assembly. Using CT scan images, three-dimensional models of shoulder bones were reconstructed. The implantation of the prosthesis in the three-dimensional model was performed in collaboration with an experienced surgeon from the Caduceus Clinic (Oran, Algeria). The numerical models were imported to finite element calculation software. After the validation of the numerical model using the literature results, we assessed the biomechanical behavior of four implantation methods under the same boundary conditions and abduction movements. From the obtained results, it was found that among the proposed methods, the BIO-SR lateralization method offers significant biomechanical advantages in terms of the forces applied to the glenoid during the abduction movement.

scholarly journals Numerical Study of Violent Impact Flow Using a CIP-Based Model

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Qiao-ling Ji ◽  
Xi-zeng Zhao ◽  
Sheng Dong
Keyword(s):  
Free Surface ◽  
Numerical Model ◽  
Large Scale ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Small Scale ◽  
Surface Boundary ◽  
Two Phase ◽  
Constrained Interpolation

A two-phase flow model is developed to study violent impact flow problem. The model governed by the Navier-Stokes equations with free surface boundary conditions is solved by a Constrained Interpolation Profile (CIP)-based high-order finite difference method on a fixed Cartesian grid system. The free surface is immersed in the computation domain and expressed by a one-fluid density function. An accurate Volume of Fluid (VOF)-type scheme, the Tangent of Hyperbola for Interface Capturing (THINC), is combined for the free surface treatment. Results of another two free surface capturing methods, the original VOF and CIP, are also presented for comparison. The validity and utility of the numerical model are demonstrated by applying it to two dam-break problems: a small-scale two-dimensional (2D) and three-dimensional (3D) full scale simulations and a large-scale 2D simulation. Main attention is paid to the water elevations and impact pressure, and the numerical results show relatively good agreement with available experimental measurements. It is shown that the present numerical model can give a satisfactory prediction for violent impact flow.

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