scholarly journals Improving the efficiency of the technology and organization of the longwall face move during the intensive flat-lying coal seams mining at the Kuzbass mines

2021 ◽  
Vol 249 ◽  
pp. 342-350
Author(s):  
Аndrey Meshkov ◽  
Oleg Kazanin ◽  
Andrey Sidorenko
Keyword(s):  
Rock Mass ◽  
Recovery Room ◽  
Longwall Mining ◽  
Three Dimensional ◽  
Longwall Face ◽  
Three Dimensional Model ◽  
Coal Seams ◽  
Sufficient Distance ◽  
Low Efficiency ◽  
Set Up

The reasons for the lag of the indicators of the leading Russian coal mines engaged in the longwall mining of the flat-lying coal seams from similar foreign mines are considered. The analysis of the efficiency of the longwall face move operations at the JSC SUEK-Kuzbass mines was carried out. A significant excess of the planned deadlines for the longwall face move during the thick flat-lying seams mining, the reasons for the low efficiency of disassembling operations and the main directions for improving the technology of disassembling operations are revealed. The directions of ensuring the operational condition of the recovery room formed by the longwall face are considered. The recommended scheme of converged coal seams mining and a three-dimensional model of a rock mass to justify its parameters are presented. Numerical studies using the finite element method are performed. The results of modeling the stress-strain state of a rock mass in the vicinity of a recovery room formed under conditions of increased stresses from the boundary part of a previously mined overlying seam are shown. The main factors determining the possibility of ensuring the operational condition of the recovery rooms are established. It is shown that it is necessary to take into account the influence of the increased stresses zone when choosing timbering standards and organizing disassembling operations at a interbed thickness of 60 m or less. A sufficient distance from the gob of above- or undermined seams was determined to ensure the operational condition of the recovery room of 50 m, for the set-up room – 30 m. Recommendations are given for improving technology and organization of the longwall face move operations at the mines applied longwall mining of flat-lying coal seams with the formation of a recovery room by the longwall face.

scholarly journals Mechanisms behind strong strata behaviour in high longwall mining face-ends under shallow covers

2019 ◽  
Vol 16 (3) ◽  
pp. 559-570 ◽  
Author(s):  
Weibing Zhu ◽  
Xiangrui Qi ◽  
Jinfeng Ju ◽  
Jingmin Xu
Keyword(s):  
Longwall Mining ◽  
Coal Pillar ◽  
Field Measurements ◽  
Main Roof ◽  
Longwall Face ◽  
Effective Control ◽  
Coal Seams ◽  
Roof Collapse ◽  
Coal Pillars ◽  
Roadway Deformation

Abstract Safe and efficient mining of shallow coal seams relies on the understanding and effective control of strata behaviour. Field measurements, theoretical analysis and numerical simulations are presented in this study to investigate the mechanism behind abnormal strata behaviour, such as roof collapse and severe roadway deformation, that occurs in high longwall face-ends under shallow cover. We observed that coal pillars with two sides being mined out become unstable when the cover depth exceeds a certain value. The instability of the coal pillar can alter the fracture line of the overlying strata, triggering a reversed rotation of the ‘curved triangle blocks’ that form after the breakage of the overlying main roof. The revolving blocks apply stress on the roof strata directly above the longwall face-end, resulting in roof collapse. The collapse of both the coal pillars and the roof also leads to the advancement and increase of the overlying abutment pressure, which further causes severe roadway deformation in front of the working face. The strong strata behaviour that occurs in high longwall face-ends with shallow cover is presented in this study and countermeasures are proposed, such as widening or strengthening the coal pillar, or implementing destress blasting. The countermeasures we proposed and the results of our analyses may facilitate the safe mining of shallow coal seams with similar problems in the future, and may improve the safety and efficient working of coal mines.

The Radial Fretting Character Research of the Shaft-Hub of Compress Impeller Based on Virtual Orthogonal Experiment

2014 ◽  
Vol 668-669 ◽  
pp. 289-293
Author(s):  
Xue Long Lu ◽  
Jun Sheng Zhao ◽  
Xin Zhong Huang ◽  
Shuang Yong Wang
Keyword(s):  
Orthogonal Experiment ◽  
Orthogonal Design ◽  
Three Dimensional ◽  
Element Model ◽  
Optimization Method ◽  
Three Dimensional Model ◽  
Interference Fit ◽  
Rotating Speed ◽  
Compressor Impeller ◽  
Set Up

A three-dimensional model of as haft-hub of compressor impeller was set up by Pro/E. Based on the ANSYS; the finite element model was established, using the analysis method of combining submodle and paramesh. The shaft-hub of compressor impeller was simulated by virtual orthogonal design optimization method. Based on the fact that there existed radial fretting in the shaft-hub interference fit joint, researching the influence significance order and law of interference, friction coefficient and rotating speed to the maximum unit frictional work , the average friction work and the optimized parameter were obtained. It turned out that the results of the numerical simulation and orthogonal experiment were accurate and reliable, with the friction and wear effectively reduced, certain guiding references to actual assembly process were got.

scholarly journals Streaming patterns in Faraday waves

2017 ◽  
Vol 819 ◽  
pp. 285-310 ◽  
Author(s):  
Nicolas Périnet ◽  
Pablo Gutiérrez ◽  
Héctor Urra ◽  
Nicolás Mujica ◽  
Leonardo Gordillo
Keyword(s):  
Three Dimensional ◽  
Navier Stokes ◽  
Faraday Waves ◽  
Three Dimensional Model ◽  
Inviscid Fluids ◽  
Streaming Velocity ◽  
The Rich ◽  
Set Up ◽  
Viscous Boundary ◽  
Streaming Flows

Wave patterns in the Faraday instability have been studied for decades. Besides the rich wave dynamics observed at the interface, Faraday waves hide elusive flow patterns in the bulk – streaming patterns – which have not been studied experimentally. The streaming patterns are responsible for a net circulation in the flow, which is reminiscent of the circulation in convection cells. In this article, we analyse these streaming flows by conducting experiments in a Faraday-wave set-up using particle image velocimetry. To visualise the flows, we perform stroboscopic measurements to both generate trajectory maps and probe the streaming velocity field. We identify three types of patterns and experimentally show that identical Faraday waves can mask streaming patterns that are qualitatively very different. Next, we consider a three-dimensional model for streaming flows in quasi-inviscid fluids, whose key is the complex coupling occurring at all of the viscous boundary layers. This coupling yields modified boundary conditions in a three-dimensional Navier–Stokes formulation of the streaming flow. Numerical simulations based on this framework show reasonably good agreement, both qualitative and quantitative, with the velocity fields of our experiments. The model highlights the relevance of three-dimensional effects in the streaming patterns. Our simulations also reveal that the variety of streaming patterns is deeply linked to the boundary condition at the top interface, which may be strongly affected by the presence of contaminants.

scholarly journals Experimental comparison of a macroscopic draping simulation for dry non-crimp fabric preforming on a complex geometry by means of optical measurement

2016 ◽  
Vol 51 (16) ◽  
pp. 2363-2375 ◽  
Author(s):  
Annegret Mallach ◽  
Frank Härtel ◽  
Frieder Heieck ◽  
Jan-Philipp Fuhr ◽  
Peter Middendorf ◽  
...  
Keyword(s):  
Measurement System ◽  
Complex Geometry ◽  
Optical Measurement ◽  
Three Dimensional ◽  
Detailed Comparison ◽  
Experimental Comparison ◽  
Three Dimensional Model ◽  
Blank Holder ◽  
Optical Measurement System ◽  
Set Up

Scope of the presented work is a detailed comparison of a macroscopic draping model with real fibre architecture on a complex non-crimp-fabric preform using a new robot-based optical measurement system. By means of a preliminary analytical process design approach, a preforming test centre is set up to manufacture dry non-crimp-fabric preforms. A variable blank holder setup is used to investigate the effect of different process parameters on the fibre architecture. The real fibre architecture of those preforms is captured by the optical measurement system, which generates a three-dimensional model containing information about the fibre orientation along the entire surface of the preform. The measured and calculated fiber orientations are then compared with the simulation results in a three-dimensional overlay file. The results show that the analytical approach is able to predict local hot spots with high shear angles on the preform. Macroscopic simulations show a higher sensitivity towards changes in blank holder pressure than reality and limit the approach to precisely predict fibre architecture parameters on complex geometries.

Modal Analysis of Two Wheels Scooter Based on Solidworks

2014 ◽  
Vol 960-961 ◽  
pp. 1420-1423
Author(s):  
Zhi Dong Huang ◽  
Guo Fei Li ◽  
Juan Cong ◽  
Yun Wang ◽  
Wei Na Yu ◽  
...  
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Three Dimensional ◽  
Element Model ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Dynamic Design ◽  
Driving System ◽  
Set Up ◽  
The Finite Element Model

Based on Solidworks software, the three-dimensional model of two wheels scooter is set up. The finite element model of two wheels scooter is generated. Modal analysis of driving system and telescopic mechanism of bar on two wheels scooter is investigated. The first five orders natural frequency and major modes of driving system and telescopic mechanism of bar are clarified. The method and the result can be used as a reference of dynamic design and lay foundation for calculation and analysis of dynamic response for the two wheels scooter.

SUBSTANTIATION OF PARAMETERS OF THE EXPERIMENT WITH THREE-DIMENSIONAL COMPUTER MODELING OF THE ROCK MASS AROUND A LONGWALL

2021 ◽  
pp. 37-48
Author(s):  
Sergey Vlasov ◽  
◽  
Yavhen Moldavanov ◽  
Keyword(s):  
Rock Mass ◽  
Computer Modeling ◽  
Coal Mining ◽  
Three Dimensional ◽  
Mining Area ◽  
Practical Significance ◽  
Coal Seams ◽  
Working Face ◽  
Powered Support ◽  
The Difference

Purpose. To substantiate the parameters of computer modeling of the mining area with a step-by-step movement of the working face, as well as taking into account the changing presence of sandstones that lie in the top of the reservoir, to predict the effect of sandstones on the nature of the distribution of convergence in the longwall and the technology of working excavation in the conditions of the mines of Western Donbass. Methods. The work uses a statistical analysis of the geological and technological conditions that are inherent in the coal mining enterprises of the Western Donbass. Also, a comparison was made of the parameters of the experiment of computer modeling of past studies, on the basis of which, a combination of new features was introduced and changed, which is aimed at choosing the optimal modeling parameters. Results. The substantiation of the parameters of the modeling experiment is presented, such as: the choice of the length of the working face, the depth of development of coal seams, the distance of the working face withdrawal from the assembly chamber, the values of the thickness of sandstones that lie in the roof of the coal seams, the choice of values of the distance of occurrence of sandstones above the roof of the coal seam, as well as geometric parameters of the computer model. Based on the justification of the parameters, a plan for conducting experiments was drawn up, the number of which was 225 units. Scientific novelty. As a result of the substantiation of the parameters, an additional combination of new features in existing studies was proposed for the first time, namely, to include in the experiment the presence of coal seams in the top – sandstones with variable thickness, the distance of occurrence above the seam, several standard sizes of the length of the working face were also included, the value of the development depth, the distance of the exit of the working face from the assembly chamber. Changing the above parameters will make it possible to compare the difference in the effect of the results of each experiment separately, depending on the change in each of the parameters, as well as to understand and generalize the idea of ​​the nature and causes of emergency longwall stops associated with the landing of powered support sections “on a hard base”. Practical significance. Substantiated modeling parameters make it possible to most adequately reflect the processes occurring in the rock mass, as well as to clarify the parameters of the reference rock pressure zones, unloading zones, as well as the nature of the change in the distribution of convergence in the longwall. The data obtained as a result of modeling can be used to select and substantiate an effective method for managing the state of the rock mass around the working excavation, which will eliminate the planting of powered support sections “on a hard base”, thereby increasing the efficiency of coal mining in the Western Donbass.

Achieve of Torpedo Shell Parameter Model Based on Secondary Development of UG

2012 ◽  
Vol 542-543 ◽  
pp. 532-536
Author(s):  
Nan Li ◽  
Yun Peng Zhao
Keyword(s):  
Design Process ◽  
Parametric Design ◽  
Three Dimensional ◽  
Secondary Development ◽  
Design Parameters ◽  
Three Dimensional Model ◽  
Three Dimensional Modeling ◽  
Modeling Software ◽  
Shell Parameter ◽  
Set Up

Torpedo shell Modeling is a very important part in the design process. However, the traditional method of torpedo shell modeling is only the GUI of CAD drawing software. If there is change in individual parameters, designers have to start again from scratch. Such method will waste of resources. This paper set up the torpedo shell parametric design process with secondary development language UG / Open API, and user-oriented menu creation tool UG / Open UIStyler of UG,which is a three-dimensional modeling software, So that designers can be directly obtained three-dimensional model of the torpedo shell needing to enter the necessary design parameters. Meanwhile the designers can save design resources, and it helps optimize the latter part of the torpedo shell design.

scholarly journals Three-Dimensional Salt Dynamics in Well-Mixed Estuaries: Influence of Estuarine Convergence, Coriolis, and Bathymetry

2017 ◽  
Vol 47 (7) ◽  
pp. 1843-1871 ◽  
Author(s):  
Xiaoyan Wei ◽  
Mohit Kumar ◽  
Henk M. Schuttelaars
Keyword(s):  
Coriolis Force ◽  
Three Dimensional ◽  
Temporal Correlation ◽  
Salt Transport ◽  
Residual Circulation ◽  
Three Dimensional Model ◽  
Coriolis Effects ◽  
Set Up ◽  
The Right ◽  
The Impact

AbstractA semianalytical three-dimensional model is set up to dynamically calculate the coupled water motion and salinity for idealized well-mixed estuaries and prognostically investigate the influence of each physical mechanism on the residual salt transport. As a study case, a schematized estuary with an exponentially converging width and a channel–shoal structure is considered. The temporal correlation between horizontal tidal velocities and tidal salinities is the dominant process for the landward residual salt transport. The residual salt transport induced by residual circulation is locally significant, but the induced salt transport integrated over the cross section is small. The impacts of the estuarine geometry, Coriolis force, and bathymetry on the salt dynamics are studied using three dedicated experiments, in which the impact of each of these factors is studied separately. To assess the impact of width convergence, a convergent estuary without bathymetric variations or Coriolis force is considered. In this experiment, the temporal correlation between tidal velocities and salinities is the only landward salt transport process. In the second experiment, Coriolis effects are included. This results in a significant residual salt transport cell due to the advection of the tidally averaged salinity by residual circulation, with salt imported into the estuary from the left side and exported on the right (looking seaward). In the last experiment, a lateral channel–shoal structure is included while the Coriolis effects are excluded. This results in a significant landward salt transport through the deeper channel and a seaward salt transport over the shoals due to the advection of the tidally averaged salinity by residual circulation.

Finite Element Optimization Design on the Back Frame of the Jaw Crusher PC5282

2012 ◽  
Vol 472-475 ◽  
pp. 2024-2028
Author(s):  
Sheng Guo ◽  
Wei Ping Huang ◽  
Nian Qing Guo
Keyword(s):  
Finite Element ◽  
Optimization Design ◽  
Static Load ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Jaw Crusher ◽  
Distribution Laws ◽  
Set Up

According to the main parameters of the jaw crusher PC5282, structure of the back frame was designed, and three-dimensional model of the back frame was also set up. Finite element analysis of the back frame under static load was done in COSMOSWORKS. The distribution laws of stress, displacement and deformation were revealed. Optimization design was also finished, and the weight of the back frame was reduced.

Finite Element Analysis of Key Component on Two Wheels Scooter

2014 ◽  
Vol 597 ◽  
pp. 531-534
Author(s):  
Zhi Dong Huang ◽  
Yun Pu Du ◽  
Bao Quan Liu ◽  
Guang Yang ◽  
Yu Feng Liu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Strain Diagram ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Innovative Design ◽  
Driving System ◽  
Set Up

Based on Solidworks software, the three-dimensional model of two wheels scooter is set up. The finite element model of two wheels scooter is generated. Finite element analysis of driving system on two wheels scooter is investigated. The stress and strain of driving system is investigated. The stress diagram and the strain diagram are obtained. The method and the result can be used as a reference of innovative design of two wheels scooter.

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