Simulation the sedimentation of a finely dispersed medium under the impact of pressure waves

2012 ◽  
Vol 9 (2) ◽  
pp. 80-85
Author(s):  
C.I. Mikhaylenko ◽  
Yu.R. Valeeva
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Disperse System ◽  
Dispersion Medium ◽  
Solid Particles ◽  
Pressure Waves ◽  
Dispersed Particles ◽  
Coagulation Of Particles ◽  
Dispersed Medium ◽  
The Impact

A mathematical model for a disperse system of gas-solid particles when passing pressure waves is decribed. The following assumptions are made: dispersed particles are capable of coagulation with increasing concentration; the dispersed particles are acted upon by the Stokes forces on the side of the dispersion medium and by gravity. The results of numerical simulation of the processes of sedimentation of a dispersed medium are presented. It is shown that one of the mechanisms of precipitation of fine disperced medium can be coagulation of particles during the passage of pressure waves.

scholarly journals Key Aspects of the Proper Formulation of the Model in Numerical Analysis of the Influence of Mining Exploitation on Buildings

2015 ◽  
Vol 36 (2) ◽  
pp. 17-28
Author(s):  
Lucyna Florkowska ◽  
Jan Walaszczyk
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Numerical Modelling ◽  
Underground Mining ◽  
Structural Characteristics ◽  
Number Of Factors ◽  
Proper Formulation ◽  
Key Aspects ◽  
The Impact ◽  
Complex Matter

Abstract Numerical modelling is an important tool used to analyse various aspects of the impact of underground mining on existing and planned buildings. The interaction between the building and the soil is a complex matter and in many cases a numerical simulation is the only way of making calculations which will take into consideration the co–existence of a number of factors which have a significant influence on the solution. The complexity of the matter also makes it a difficult task to elaborate a proper mathematical model – it requires both a thorough knowledge of geologic conditions of the subsoil and the structural characteristics of the building. This paper discusses the most important problems related to the construction of a mathematical model of a building-mining subsoil system. These problems have been collected on the basis of many years of experience the authors have in observing the surveying and tensometric deformations of the rock–mass and buildings as well as in mathematical and numerical modelling of the observed processes.

Mathematical model of energy conversion mechanism in screw centrifugal pump based on load criteria of blade airfoil

2017 ◽  
Vol 34 (7) ◽  
pp. 2168-2188 ◽  
Author(s):  
Hui Quan ◽  
Baiheng Fu ◽  
Rennian Li ◽  
Guangxian Li ◽  
Zhengjie Zhang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Energy Transfer ◽  
Energy Conversion ◽  
Centrifugal Pump ◽  
Lift Coefficient ◽  
Energy Conversion Efficiency ◽  
Solid Particles ◽  
Content Type ◽  
Wrap Angle

Purpose To analyze the work principle and capacity of energy conversion in each segment of profile lines, the energy transfer from impeller to transmission medium is separated into head coefficient and load coefficient to analyze the energy transfer process. The concepts of airfoil lift coefficient and drag coefficient are used; the third manifestation of the Euler equations is used as well. Design/methodology/approach The numerical simulation of energy conversion mechanism based on load criteria of vane airfoil has been established in screw centrifugal pump to explain its energy conversion mechanism in an impeller. Upon this basis, the velocity and pressure along the entire blade are investigated through the numerical simulation of internal solid–liquid flow in the pump. The energy conversion process under load criteria in the blade airfoil has also been obtained. Findings The research suggests that the mathematical model of energy conversion mechanism based on the load criteria of the vane airfoil is reliable in the screw centrifugal pump. The screw centrifugal blade has twice or even several times the wrap angle than the ordinary centrifugal blade. It is a large wrap angle that forms the unique flow channel which lays the foundation for solid particles to pass smoothly and for soft energy conversion. At the same time, load distribution along the profile line on the long-screw centrifugal blade is an important factor affecting the energy conversion efficiency of the impeller. Originality/value The quantitative analysis method of energy in the screw centrifugal pump can help the pump designer improve certain features of the pump and shorten the research cycle.

NUMERICAL SIMULATION OF THE PROPAGATION OF A GAS SHOCK WAVE IN ELECTRICALLY CHARGED AND NEUTRAL GAS SUSPENSION IN A FLAT CHANNEL

2020 ◽  
Vol 2 ◽  
pp. 9-18
Author(s):  
D.A. TUKMAKOV
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Shock Wave ◽  
Solid Particles ◽  
Grid Function ◽  
Heat Conducting ◽  
Gas Suspension ◽  
Carrier Medium ◽  
The Mathematical Model ◽  
Electrically Charged

In this paper, we consider the propagation of a shock wave from a pure gas into a heterogeneous mixture consisting of solid particles suspended in a gas and having an electric charge. The applied mathematical model takes into account the speed and thermal interaction of the carrier and dispersed components of the mixture. The force interaction of particles and gas was described by the Stokes force. The carrier medium was described as a viscous compressible heat–conducting gas. The equations of the mathematical model were solved by the explicit finite–difference method of the second order of accuracy, using the non–linear correction of the grid function. The system of equations of the mathematical model was supplemented by boundary and initial conditions for the desired functions. As a result of numerical simulation, it was found that in an electrically charged gas suspension there is a difference in gas pressure and velocity, “average density” and velocity of the dispersed component, compared with similar values in a gas suspension with an electrically neutral dispersed component. The revealed differences in the dynamics of neutral and electrically charged dusty media can be explained by the fact that the dispersed component of an electrically charged gas suspension is affected by both aerodynamic drag forces and Coulomb forces. Due to interfacial interaction, the dynamics of the carrier medium changes.

The Numerical Simulation and Performance Analysis of the Vortex Pump for Solid-Liquid Two Phase Medium

2014 ◽  
Vol 527 ◽  
pp. 88-92
Author(s):  
Peng Yun Song ◽  
Hong Li Wang ◽  
Peng Cheng He
Keyword(s):  
Numerical Simulation ◽  
Volume Fraction ◽  
Internal Flow ◽  
Solid Particles ◽  
Two Phase ◽  
Pump Head ◽  
Phase Medium ◽  
And Performance ◽  
Solid Liquid ◽  
The Impact

The numerical simulation of a 3-D model of the internal flow field for a Vortex slurry pump has been analyzed in this paper. The impact of different solids volume fraction on the distribution of solid particle was analyzed. The expression of the pump head and efficiency was derived by the energy equation. The results show that either on the long blades or on the short blades, the content of the solid particles increases with the increasing of the volume fraction. The results by the expression of the pump head and efficiency are compared with the results of the simulations. The conclusions show that the expression results are similar with the numerical simulation results, and the main factors of affecting the inner and outer characteristics are the solid particles.

scholarly journals An SVEIRE Model of Tuberculosis to Assess the Effect of an Imperfect Vaccine and Other Exogenous Factors

Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 327 ◽  
Author(s):  
Fatima Sulayman ◽  
Farah Aini Abdullah ◽  
Mohd Hafiz Mohd
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Disease Burden ◽  
Backward Bifurcation ◽  
Effective Control ◽  
General Effect ◽  
Tuberculosis Transmission ◽  
Proposed Model ◽  
Exogenous Factors ◽  
The Impact

This study extends a deterministic mathematical model for the dynamics of tuberculosis transmission to examine the impact of an imperfect vaccine and other exogenous factors, such as re-infection among treated individuals and exogenous re-infection. The qualitative behaviors of the model are investigated, covering many distinct aspects of the transmission of the disease. The proposed model is observed to show a backward bifurcation, even when Rv<1. As such, we assume that diminishing Rv to less than unity is not effective for the elimination of tuberculosis. Furthermore, the results reveal that an imperfect tuberculosis vaccine is always effective at reducing the spread of infectious diseases within the population, though the general effect increases with the increase in effectiveness and coverage. In particular, it is shown that a limited portion of people being vaccinated at steady-state and vaccine efficacy assume a equivalent role in decreasing disease burden. From the numerical simulation, it is shown that using an imperfect vaccine lead to effective control of tuberculosis in a population, provided that the efficacy of the vaccine and its coverage are reasonably high.

scholarly journals MATHEMATICAL MODEL OF THE DYNAMICS DISPERSED MEDIA IN THE SHAPING PROCESSES BILLETS OF POWDER METALLURGY

2021 ◽  
pp. 70-75
Author(s):  
Yaroslav Ivanchuk ◽  
Rostislav Iskovych-Lototsky ◽  
Ivan Sevostianov ◽  
Natalia Veselovska ◽  
Olexander Manzhilevskyy
Keyword(s):  
Differential Equation ◽  
Mathematical Model ◽  
Powder Metallurgy ◽  
Local Area ◽  
Dynamic Force ◽  
Powder Metal ◽  
Various Boundary Conditions ◽  
Dispersed Particles ◽  
Dispersed Medium ◽  
Vibration Compaction

A mathematical model has been developed for changing the dynamics of the movement of a dispersed medium in vibro-impact technological processes of shaping of powder metallurgy blanks. On the basis of the problem of two-dimensional dynamic interaction of dispersed particles of powder metal of a spacer dispersed medium, the obtained differential equation in partial derivatives under various boundary conditions. This equation describes the state of the local area of the dispersed medium. In it, the powder material of the workpiece passes from the concentrated dynamic force to the excitation phase. A partial differential equation is obtained. It describes the change in normal stress during vibrations of a dispersed medium during vibration compaction of a workpiece in powder metallurgy.

A MATHEMATICAL MODEL TO STUDY THE IMPACT OF MINING ACTIVITIES AND POLLUTION ON FOREST RESOURCES AND WILDLIFE POPULATION

2017 ◽  
Vol 25 (02) ◽  
pp. 207-230 ◽  
Author(s):  
KUMARI JYOTSNA ◽  
ABHINAV TANDON
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Environmental Pollution ◽  
Forest Resources ◽  
Mining Activities ◽  
Nonlinear Mathematical Model ◽  
Wildlife Population ◽  
Constant Rate ◽  
The Impact ◽  
Impact Of Mining

In this paper, we develop a nonlinear mathematical model that investigates the impact of mining activities and pollution on forest resources and wildlife population. It is assumed that concentration of pollutants grows in the environment at a constant rate and also augments due to different mining activities prevailing in the forest area. The model is formulated in terms of differential equations and analyzed using elements of stability theory and numerical simulation. The obtained results depict that both forest resources as well as wildlife population get very much affected, either directly or indirectly, due to mining activities and environmental pollution. It is being concluded that, in order to save forests, an ecological balance is required to be maintained among forest resources, forest-dependent wildlife population, mining activities and environmental pollution.

scholarly journals MODELING OF A DUSTED GAS FLOW CLEANING PROCESS USING A KINEMATIC MODEL OF THE INTERACTION OF DISPERSED PARTICLES WITH DROPLETS IN A WET SCRUBBER

2021 ◽  
pp. 84-98
Author(s):  
I.A. Volchyn ◽  
V.A. Raschepkin
Keyword(s):  
Mathematical Model ◽  
Gas Flow ◽  
Kinematic Model ◽  
Significant Proportion ◽  
Solid Particles ◽  
Venturi Tube ◽  
Gas Cleaning ◽  
Dispersed Particles ◽  
Spray Density ◽  
Wet Scrubber

A mathematical model is proposed for the scavenging process of the dispersed particles by droplets in a wet scrubber under excess spray density in Venturi tube within kinematic approach of the interaction of particles in countercurrent gas-dispersed flows, which refines the existing engineering model, taking into account the spatial size variation of the droplets, due to their coagulation with wet slurry droplets and uncaptured particles entering a wet scrubber from the Venturi tube. The results of calculations with the adopted mathematical model showed that in case of possibility to organize the spraying of a gas flow in a scrubber with 300–500 micron droplets aerosol at a specific spray density of about 1 liter/m3, a 1–2 meters wide layer of droplets ensures effective absorption of both uncaptured PM2.5 solid particles, and the slurry droplets from the Venturi tube. The ejection of the slurry droplets into a wet scrubber from the Venturi tube, and the associated increase in the size of the scrubber droplets due to coagulation with slurry droplets, does not noticeably affect the efficiency of the dusted gas stream cleaning. An adopted mathematical model was applied to calculate the capture of particles by droplets in cylindrical and conical scrubbers. Due to the increase in a residence time of the droplets upon increased velocity of the countercurrent gas flow, the efficiency of gas cleaning from dispersed particles in a conical scrubber appears to be higher than in a cylindrical scrubber. However, with an increase in the spray density above 2 liter/m3 and with droplet diameters greater than 1000 microns, the efficiency of the conical scrubber decreases, which is associated to an increase in the escape of a significant proportion of massive drops to the walls with a reduction in the scrubber reactor cross-section.  Bibl. 21, Fig. 4.

scholarly journals Separation of Fine Particles from Gas in Paint-Spraying Booths

2021 ◽  
Vol 346 ◽  
pp. 03070
Author(s):  
Rustem Ya. Bikkulov ◽  
Andrey V. Dmitriev ◽  
Vadim E. Zinurov ◽  
Guzel R. Badretdinova
Keyword(s):  
Gas Flow ◽  
Fine Particles ◽  
Solid Particles ◽  
Dust Particles ◽  
Technological Parameters ◽  
Separation Device ◽  
Dispersed Particles ◽  
Quality Of Products ◽  
The Impact

Nowadays, at production facilities with paint-spraying booths that use paint and varnish materials to cover the surfaces of product, the problem of gas flow contamination with finely dispersed solid particles of dust and rubbish, which negatively affect the quality of products, is increasingly being raised. In order to minimize the content of solid particles in the gas flow, coarse and fine filters are installed in the paint-spraying booths, which prevent dust particles from entering the surface of products. However, the existing purification devices have a number of disadvantages that affect the efficiency of collecting finely dispersed particles from the gas flow with a size of 0.5-5 microns. The authors of article developed a square separator to increase the efficiency of collecting finely dispersed particles from gas flows in the paint-spraying booths. The installation of proposed separation device in the paint-spraying booths affects not only the quality of collecting solid particles, but also increases the service life of fine and coarse filters In the course of numerical studies, the results of impact of structural and technological parameters, namely, the impact of inlet rate and scale of separation device on the efficiency of collecting solid particles from the gas flow, were obtained.

Sign in / Sign up

Export Citation Format

Share Document