INFLUENCE OF MASSIVE PARAMETERS ON THE DEGREE OF COMPENSATION OF THE BREED BOOK

Intensive and massive coal mining causes a series of geological hazards and environmental problems, especially surface subsidence. At present, two major types of subsidence control technology are applied: backfilling technology and partial mining technology. However, the cost of backfill mining is high and partial mining has a low recovery ratio. Therefore, the backfill-strip mining is used to solve the problems of high cost and shortage of filling materials in coal mines at present. A subsidence control design method of backfill-strip mining was proposed in this paper based on the subsidence control effects and economic benefits. First, the stability of the composite support pillar of the filling body and coal pillars in the backfill-strip mining is analyzed, and the values of the main subsidence influencing factors that include the filling material, the size of the backfilling working face, caving mining face, and residual coal pillar are preliminarily determined. Then, the surface movement and deformation are predicted based on the equivalent superposition probability integral method (PIM). The subsidence influencing factors are optimized and determined by comparing the requirements of the safety fortification index of the antideformation ability of surface buildings, resource recovery rate, and coal mining cost. Finally, the mining scheme design parameters of the backfill-strip mining technology are determined. This method is applied in the subsidence control design of backfill-strip mining in the Ezhuang coal mine. Research results show that backfill-strip mining can ensure the safety of surface buildings, increase the resource recovery rate, and reduce coal mining costs through the reasonable design of this method. This study can provide scientific guidance for subsidence disaster control, prevention, and engineering design in backfill-strip mining.

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DETERMINATION OF DESIGN PARAMETERS OF A STEP DISK MILL

Bulletin of Belgorod State Technological University named after V G Shukhov ◽

10.34031/2071-7318-2021-6-12-98-105 ◽

2021 ◽

Vol 6 (12) ◽

pp. 98-105

Author(s):

I. Semikopenko ◽

V. Voronov ◽

S. Latyshev ◽

V. Sevost'yanov ◽

L. Rybak ◽

...

Keyword(s):

Volumetric Flow Rate ◽

Throughput Capacity ◽

Design Parameters ◽

Technological Parameters ◽

Crushed Material ◽

High Rotational Speed ◽

Working Chamber ◽

Working Zone ◽

Disk Mill ◽

The Impact

The calculation of the design parameters of a disc mill equipped with a feeder made in the form of a conical hopper is given. For shredders of the disintegrator type, it is very important to ensure the uniformity of loading of the crushed material of the working zone of active impact on particles. In addition, the most important factor is the throughput capacity of all sections of the grinding plant. The throughput should be determined by the design and technological parameters of the working chamber of the mill. Its overload can lead to a blockage of the working chamber, and insufficient throughput will negatively affect the intensity and effectiveness of the impact on the particles of the material. For example, insufficient concentration of particles in the secondary zone of the grinding chamber leads to a decrease in the efficiency of mutual abrasion. The article attempts to determine the design and technological parameters in the loading and accelerating parts of the disk mill. At the same time, it is necessary to coordinate the throughput of the disk spreader and the volumetric flow rate of the material particles flowing from the hopper. In this case, it is advisable to take into account that as a result of a rather high rotational speed and the size of the initial particles, with the wrong height of the radial blade of the spreader, material particles can roll over the radial blades, which leads to a delay of the material in the zone of the spreading disc. Therefore, it is necessary to determine the calculation formulas for finding the required height of the radial blade of the spreading disc, depending on the size of the initial particles. The formula demonstrates that the height of the separating blade depends on the particle size, the speed of rotation of the disks and the distance to the point of meeting of the particle with the radial blade.

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Design Optimization and Performance Analysis of the Pneumatic DTH Hammer with Self-Propelled Round Bit

Shock and Vibration ◽

10.1155/2021/6653390 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Kun Bo ◽

Siyuan Sun ◽

Yong Hu ◽

Maosen Wang

Keyword(s):

Oil And Gas ◽

Vertical Section ◽

Dynamics Simulation ◽

Chamber Pressure ◽

Design Parameters ◽

The Novel ◽

Directional Drilling ◽

Pressure Impact ◽

Working Principle ◽

And Performance

Although pneumatic down-the-hole (DTH) hammers have good performance of high penetration rate and minimal deviation tendency in the vertical section of oil and gas wells, they have not been successfully used in directional drilling due to drill tool wear and wellbore disturbance. Herein, we developed a novel type of pneumatic DTH hammer with a self-propelled round bit to overcome the technical difficulties of directional drilling. Nonlinear dynamic modeling developed by the authors was used to analyze the working principle and performance of the novel DTH hammer. The kinematics and dynamics simulation of this hammer were carried out using MATLAB language, and the motion law of the piston was revealed. The performance of the novel hammer was numerically simulated and evaluated by considering fluctuations of the front and rear chamber pressure, impact energy, acceleration, and frequency. The results show that our novel DTH hammer’s working principle is feasible and has an adequate structural design. The simulation results demonstrate reasonable design parameters. Compared to the numerical results for conventional DTH hammers, the velocity and acceleration of the piston of the novel hammer changed smoothly. The frequency was slightly higher than that of conventional hammers, while other parameters were nearly equal. The novel DTH hammer can be used in directional drilling, trenchless drilling, and seabed sampling drilling.

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DETERMINATION OF DESIGN PARAMETERS OF A STEP DISK MILL

Bulletin of Belgorod State Technological University named after V G Shukhov ◽

10.34031/2071-7318-2021-6-12-98-106 ◽

2021 ◽

pp. 98-106

Author(s):

I. Semikopenko ◽

V. Voronov ◽

S. Latyshev ◽

V. Sevost'yanov ◽

L. Rybak ◽

...

Keyword(s):

Volumetric Flow Rate ◽

Throughput Capacity ◽

Design Parameters ◽

Technological Parameters ◽

Crushed Material ◽

High Rotational Speed ◽

Working Chamber ◽

Working Zone ◽

Disk Mill ◽

The Impact

The calculation of the design parameters of a disc mill equipped with a feeder made in the form of a conical hopper is given. For shredders of the disintegrator type, it is very important to ensure the uniformity of loading of the crushed material of the working zone of active impact on particles. In addition, the most important factor is the throughput capacity of all sections of the grinding plant. The throughput should be determined by the design and technological parameters of the working chamber of the mill. Its overload can lead to a blockage of the working chamber, and insufficient throughput will negatively affect the intensity and effectiveness of the impact on the particles of the material. For example, insufficient concentration of particles in the secondary zone of the grinding chamber leads to a decrease in the efficiency of mutual abrasion. The article attempts to determine the design and technological parameters in the loading and accelerating parts of the disk mill. At the same time, it is necessary to coordinate the throughput of the disk spreader and the volumetric flow rate of the material particles flowing from the hopper. In this case, it is advisable to take into account that as a result of a rather high rotational speed and the size of the initial particles, with the wrong height of the radial blade of the spreader, material particles can roll over the radial blades, which leads to a delay of the material in the zone of the spreading disc. Therefore, it is necessary to determine the calculation formulas for finding the required height of the radial blade of the spreading disc, depending on the size of the initial particles. The formula demonstrates that the height of the separating blade depends on the particle size, the speed of rotation of the disks and the distance to the point of meeting of the particle with the radial blade.

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Research and development of the structure of a vortex heat generator by the method of mathematical modeling

Technology audit and production reserves ◽

10.15587/2706-5448.2021.225289 ◽

2021 ◽

Vol 1 (1(57)) ◽

pp. 39-43

Author(s):

Vadim Yaris ◽

Ivan Kuzyayev ◽

Valeriy Nikolsky ◽

Viktor Ved ◽

Chlens Peter ◽

...

Keyword(s):

Mathematical Modeling ◽

Energy Efficiency ◽

Rectangular Cross Section ◽

Geometric Parameters ◽

Design Parameters ◽

Variable Geometry ◽

Flow Area ◽

Heat Generator ◽

Vortex Zone ◽

Working Space

The object of research is a mathematical model of a new design of a vortex heat generator with translational-rotational flow in a variable geometry working space. One of the most problematic areas in the development of new and promising designs of heat generators by the method of physical modeling is the search for its optimal operating-technological and instrumental-design parameters. The implementation of a preliminary analysis of such structures by the method of mathematical modeling will significantly reduce the time and material costs for the development of promising designs of heat generators. The studies of the design of the new vortex heat generator, carried out by the method of mathematical modeling, made it possible to determine the range of its operation, to evaluate the operating-technological and hardware-design parameters that affect the efficiency of work. Studies of the hydrodynamics of the translational-rotational motion of a viscous fluid flow in the working space of a new vortex heat generator with a variable geometry of the working space made it possible to determine the critical velocity and pressure, the influence of the geometric parameters of the device on the generation of vortices that promote cavitation. Model studies were carried out in the range of fluid load changes in the range from 0.001 m3/s to 0.01 m3/s. The study of changes in the velocity field in the channels was carried out for the geometry of the channel with a taper angle from 0° to 25°. The width of the working channel of the space Wn varied in the range of 130, 70 and 40 mm. It has been established that a good axial symmetry and smoothness of the coolant flow in the vortex zone along the swirler screw provides the coolant inlet through a nozzle with a rectangular cross-section. The dependence of the influence of the flow area of the nozzle for introducing the coolant into the vortex zone on the energy efficiency of the vortex apparatus as a whole is found experimentally. The research carried out makes it possible to design vortex heat generators with geometric parameters that meet modern energy efficiency requirements. The geometry of the swirler screw is determined, which increases the efficiency of the heat generator by 35 % in comparison with similar designs of vortex heat generators given in the literature.

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MATHEMATICAL MODEL TO CALCULATE THE TRAJECTORIES OF ELECTROMAGNETIC MILL OPERATING ELEMENTS

Tekhnichna Elektrodynamika ◽

10.15407/techned2021.02.026 ◽

2021 ◽

Vol 2021 (2) ◽

pp. 26-34

Author(s):

O. Makarchuk ◽

◽

D. Calus ◽

V. Moroz ◽

◽

...

Keyword(s):

Magnetic Field ◽

Mathematical Model ◽

Driving Forces ◽

Fem Analysis ◽

Plane Motion ◽

Rotating Magnetic Field ◽

Hydrodynamic Resistance ◽

Design Parameters ◽

Two Dimensional ◽

Working Chamber

The purpose of the research under consideration is to develop a mathematical model to calculate the trajectories of the ferromagnetic operating elements (millstones) of an electromagnetic mill, moving in a rotating magnetic field under electrodynamic and hydrodynamic resistance forces being limited by the space of the mill’s working chamber. The millstone motion is described through the equations of plane motion of arbitrary-shaped two-dimensional body. The driving forces of this motion are determined on the basis of the approximation of the tabulated functions connecting the module and the orientation of the equivalent force applied to the millstone, with its position in the working chamber and composite MMF phase of mill inductor winding. These tabulated functions are derived from the estimation of the magnetic field inside a working chamber with millstones, in two-dimensional quasi-stationary approximation, using FEM analysis. The publication contains the approximation algorithm for these tabulated vector functions of a vector argument, mathematical statement of millstones trajectories calculating, and analysis of mathematical experiments results that make it possible to evaluate the adequacy of the model. The developed tool enables conducting quantitative analysis of grinding/mixing process and will help to establish relationships between the electromagnetic mill design parameters and its performance. References 21, figures 6.

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Fan-Intake Interaction Under High Incidence

Volume 1: Aircraft Engine; Fans and Blowers; Marine ◽

10.1115/gt2016-56561 ◽

2016 ◽

Cited By ~ 3

Author(s):

Teng Cao ◽

Nagabhushana Rao Vadlamani ◽

Paul G. Tucker ◽

Angus R. Smith ◽

Michal Slaby ◽

...

Keyword(s):

Numerical Study ◽

Design Parameters ◽

Angle Of Incidence ◽

Flow Distortion ◽

Distortion Level ◽

3D Geometry ◽

High Incidence ◽

Unsteady Rans ◽

Bypass Ratio ◽

Insight Into

In this paper, we present an extensive numerical study on the interaction between the downstream fan and the flow separating over an intake under high incidence. The objectives of this investigation are twofold: (a) to gain qualitative insight into the mechanism of fan-intake interaction and (b) to quantitatively examine the sensitivity of the flow distortion (in terms of distortion coefficient DC60), to the key design parameters of the intake (Length, L / Diameter, D). Both steady and unsteady Reynolds Averaged Numerical Simulations (RANS) were carried out. For the steady calculations, a low order fan model has been used while a full 3D geometry has been used for the unsteady RANS. The numerical methodology is also thoroughly validated against the measurements for the intake-only and fan-only configurations on a high bypass ratio turbofan intake and fan respectively. To systematically study the effect of fan on the intake separation and explore the design criteria, a simplified intake-fan configuration has been considered. In this fan-intake model, the ratio of the intake length to diameter (L/D) can be conveniently altered without affecting other parameters. The key results indicate that, depending on L/D, the fan has either suppressed the level of the post separation distortion or increased the separation-free operating range. At the lowest L/D (∼ 0.17), around a 5° increase in the separation-free angle of incidence was achieved. This delay in the separation-free angle of incidence decreased with increasing L/D. At the largest L/D (∼ 0.44), the fan was effective in suppressing the post-separation distortion rather than entirely eliminating the separation. Isentropic Mach number distributions over the intake lip for different L/D’s revealed that the fan accelerates the flow upstream of the fan face, thereby decreasing the distortion level in the immediate vicinity. However, this acceleration effect decayed rapidly with increasing upstream distance from the fan-face.

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Aerodynamic Investigations of Root Sections of Long Rotor Blades Applied at the Last Stages of Steam Turbines

Volume 8: Turbomachinery, Parts A, B, and C ◽

10.1115/gt2012-68043 ◽

2012 ◽

Cited By ~ 1

Author(s):

David Šimurda ◽

Martin Luxa ◽

Pavel Šafařík ◽

Jaroslav Synáč ◽

Miroslav Šťastný

Keyword(s):

Rotor Blades ◽

Design Parameters ◽

Angle Of Incidence ◽

Steam Turbines ◽

Turbine Stage ◽

Flow Angle ◽

Root Section ◽

The Difference ◽

Kinetic Energy Loss ◽

Large Output

The aerodynamics of root sections appears to be a crucial problem in the design and operation of the last stages of large output steam turbines. The reasons are transonic flow, high flow turning, and difficulties with keeping their design aerodynamic conditions during operation. Investigations were performed on planar blade cascades representing root sections of 1085mm and 1220mm long rotor blades. The basic conception of the two root sections differs. The aerodynamic loading of the 1220mm blade root section is lowered in order to ensure that the design parameters are kept during turbine stage operation. We present the results of optical and pneumatic measurements i.e. dependencies of the kinetic energy loss coefficient and exit flow angle on the exit isoentropic Mach number and the angle of incidence, as well as images of the flow fields. The experimental data is analyzed in order to assess and document the difference between the two root section designs.

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Electron Channeling Patterns

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077700 ◽

1977 ◽

Vol 35 ◽

pp. 12-13

Author(s):

David C. Joy

Keyword(s):

Electron Diffraction ◽

Incidence Angle ◽

Photographic Plate ◽

Diffraction Effect ◽

Angle Of Incidence ◽

Bulk Single Crystal ◽

Time Resolved ◽

Electron Channeling ◽

Spatially Resolved ◽

Large Bulk

Electron channeling patterns (ECP) were first found by Coates (1967) while observing a large bulk, single crystal of silicon in a scanning electron microscope. The geometric pattern visible was shown to be produced as a result of the changes in the angle of incidence, between the beam and the specimen surface normal, which occur when the sample is examined at low magnification (Booker, Shaw, Whelan and Hirsch 1967).A conventional electron diffraction pattern consists of an angularly resolved intensity distribution in space which may be directly viewed on a fluorescent screen or recorded on a photographic plate. An ECP, on the other hand, is produced as the result of changes in the signal collected by a suitable electron detector as the incidence angle is varied. If an integrating detector is used, or if the beam traverses the surface at a fixed angle, then no channeling contrast will be observed. The ECP is thus a time resolved electron diffraction effect. It can therefore be related to spatially resolved diffraction phenomena by an application of the concepts of reciprocity (Cowley 1969).

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Electron-Channelling Patterns: Principles and Techniques

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100091986 ◽

1976 ◽

Vol 34 ◽

pp. 400-401

Author(s):

David C. Joy

Keyword(s):

Crystal Structure ◽

Electron Flux ◽

Lattice Structure ◽

Incident Beam ◽

Bloch Wave ◽

Crystalline Solid ◽

Angle Of Incidence ◽

Electron Channelling ◽

Regular Arrangement ◽

Backscattered Signals

In a crystalline solid the regular arrangement of the lattice structure influences the interaction of the incident beam with the specimen, leading to changes in both the transmitted and backscattered signals when the angle of incidence of the beam to the specimen is changed. For the simplest case the electron flux inside the specimen can be visualized as the sum of two, standing wave distributions of electrons (Fig. 1). Bloch wave 1 is concentrated mainly between the atom rows and so only interacts weakly with them. It is therefore transmitted well and backscattered weakly. Bloch wave 2 is concentrated on the line of atom centers and is therefore transmitted poorly and backscattered strongly. The ratio of the excitation of wave 1 to wave 2 varies with the angle between the incident beam and the crystal structure.

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